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Kawasaki FH601V Compression Question
#1
B
Beau
B
Beau
Hi,
need a little help with a compression question if anyone has any ideas here. As the post title says i have a Kaw. FH601V that I cant get to turn over. Getting plenty of spark and fuel and nothing. I checked the compression on the cylinders. I'm getting 75psi out of the left cylinder and 25psi out of the right. Which on outboards and motorcycles, which is what I've got a little experience with, would indicate a bad cylinder. But I wasn't sure if these engines have some type of compression release system and is why one of the cylinders is showing such low compression.
Any insight would be greatly appreciated.
Thanks
need a little help with a compression question if anyone has any ideas here. As the post title says i have a Kaw. FH601V that I cant get to turn over. Getting plenty of spark and fuel and nothing. I checked the compression on the cylinders. I'm getting 75psi out of the left cylinder and 25psi out of the right. Which on outboards and motorcycles, which is what I've got a little experience with, would indicate a bad cylinder. But I wasn't sure if these engines have some type of compression release system and is why one of the cylinders is showing such low compression.
Any insight would be greatly appreciated.
Thanks
#2
B
bertsmobile1
B
bertsmobile1
Start with checking the valve lash as per the manual that you will find on either the Kawasaki web site on on this one https://mymowerparts.com/about_us.php
#3
B
Beau
B
Beau
Thanks. I pulled the valve covers to be sure everything was moving as it should but didn’t check the clearance. Didn’t think that would have anything to do with the actual compression.
Start with checking the valve lash as per the manual that you will find on either the Kawasaki web site on on this one https://mymowerparts.com/about_us.php
#4
Fish
Fish
Put up some pics with the valve covers off. Rotate the flywheel and take several pics.
#5
B
bertsmobile1
B
bertsmobile1
the valve lash affects when the valve opens & closes
The bigger the lash the latter the valve opens & the sooner it closes
This affect how much gets into the cylinder in the first place which will affect the final compression figures.
If your engine has ACR then too little valve lsh will open the cylinder for too long on the compression stroke again lowering the compression.
Because the compression is so dependent upon valve lash, a strait compression number is not much use.
Having said that anything less than around 60 psi & the engine will have difficulty starting .
Also they type of meter, how you do the test will also affect the reading.
A wide open throttle will reach peak reading in 4 to 5 cycles, a closed throttle can take 30 or more.
Remove the dip stick, turn the engine over by hand and listen for the sound of air escaping as the pistons approach TDC compression stroke ( watch the rockers to confirm this ) .
If it whooshes, or hisses then the head gasket is gone.
Do the same at the carb & exhaust, whooses at the wrong time indicates valve problems.
A leak down is a better test.
Also please be careful with your descriptions because all we have is the words you type
Turn over is considered to mean rotate not start or run.
The bigger the lash the latter the valve opens & the sooner it closes
This affect how much gets into the cylinder in the first place which will affect the final compression figures.
If your engine has ACR then too little valve lsh will open the cylinder for too long on the compression stroke again lowering the compression.
Because the compression is so dependent upon valve lash, a strait compression number is not much use.
Having said that anything less than around 60 psi & the engine will have difficulty starting .
Also they type of meter, how you do the test will also affect the reading.
A wide open throttle will reach peak reading in 4 to 5 cycles, a closed throttle can take 30 or more.
Remove the dip stick, turn the engine over by hand and listen for the sound of air escaping as the pistons approach TDC compression stroke ( watch the rockers to confirm this ) .
If it whooshes, or hisses then the head gasket is gone.
Do the same at the carb & exhaust, whooses at the wrong time indicates valve problems.
A leak down is a better test.
Also please be careful with your descriptions because all we have is the words you type
Turn over is considered to mean rotate not start or run.
#6
Fish
It might hurt.....
Just put up a few pics....
Fish
Yes, don't stick your dick in the flywheel...the valve lash affects when the valve opens & closes
The bigger the lash the latter the valve opens & the sooner it closes
This affect how much gets into the cylinder in the first place which will affect the final compression figures.
If your engine has ACR then too little valve lsh will open the cylinder for too long on the compression stroke again lowering the compression.
Because the compression is so dependent upon valve lash, a strait compression number is not much use.
Having said that anything less than around 60 psi & the engine will have difficulty starting .
Also they type of meter, how you do the test will also affect the reading.
A wide open throttle will reach peak reading in 4 to 5 cycles, a closed throttle can take 30 or more.
Remove the dip stick, turn the engine over by hand and listen for the sound of air escaping as the pistons approach TDC compression stroke ( watch the rockers to confirm this ) .
If it whooshes, or hisses then the head gasket is gone.
Do the same at the carb & exhaust, whooses at the wrong time indicates valve problems.
A leak down is a better test.
Also please be careful with your descriptions because all we have is the words you type
Turn over is considered to mean rotate not start or run.
It might hurt.....
Just put up a few pics....
#7
Fish
Fish
These engines have compression releases, but who can tell what your trouble is, without more info....
#8
Fish
Fish
Or just give up and blame Trump?
#9
B
Beau
Promise not to stick my dick in the fly wheel...or my dipstick.
B
Beau
Yes, don't stick your dick in the flywheel...
It might hurt.....
Just put up a few pics....
Promise not to stick my dick in the fly wheel...or my dipstick.
#10
B
Beau
By turn over, yes I guess I meant spinning but won’t start.
I’ll take some pics and post them but won’t be for a few days. Mardi Gras down here and my girls have me tied up after this evening.
Thanks again!
B
Beau
Thanks! Lot of good information. I did hear the sucking of air when I was checking to see if the valves had movement but not sure where it was coming from.the valve lash affects when the valve opens & closes
The bigger the lash the latter the valve opens & the sooner it closes
This affect how much gets into the cylinder in the first place which will affect the final compression figures.
If your engine has ACR then too little valve lsh will open the cylinder for too long on the compression stroke again lowering the compression.
Because the compression is so dependent upon valve lash, a strait compression number is not much use.
Having said that anything less than around 60 psi & the engine will have difficulty starting .
Also they type of meter, how you do the test will also affect the reading.
A wide open throttle will reach peak reading in 4 to 5 cycles, a closed throttle can take 30 or more.
Remove the dip stick, turn the engine over by hand and listen for the sound of air escaping as the pistons approach TDC compression stroke ( watch the rockers to confirm this ) .
If it whooshes, or hisses then the head gasket is gone.
Do the same at the carb & exhaust, whooses at the wrong time indicates valve problems.
A leak down is a better test.
Also please be careful with your descriptions because all we have is the words you type
Turn over is considered to mean rotate not start or run.
By turn over, yes I guess I meant spinning but won’t start.
I’ll take some pics and post them but won’t be for a few days. Mardi Gras down here and my girls have me tied up after this evening.
Thanks again!
#11
Fish
Fish
Yeah, turning the flywheel by hand wile watching the valves/rockers,
usually tells you a lot.
Look the the valve stems while the rocker arms are not touching them, also looks for leaking compression, whooshing out, lots of possibilities....
Looking is the best tool you have. Will save you a lot of time and money, usually....
Your own eyes are the best tool you have...
Pics let us other guys have a look as well.
Making guesses online with little info.....
Well, not much value.....
The main thing is to find out what the problem is without spending a lot of money...
usually tells you a lot.
Look the the valve stems while the rocker arms are not touching them, also looks for leaking compression, whooshing out, lots of possibilities....
Looking is the best tool you have. Will save you a lot of time and money, usually....
Your own eyes are the best tool you have...
Pics let us other guys have a look as well.
Making guesses online with little info.....
Well, not much value.....
The main thing is to find out what the problem is without spending a lot of money...
#12
B
bertsmobile1
B
bertsmobile1
Funny you should say that .
It was mardi-Gras here last night
However I definately was not there.
Leather undies chaff way too much and sequined undies prickle.
It was mardi-Gras here last night
However I definately was not there.
Leather undies chaff way too much and sequined undies prickle.
#13
Fish
Fish
Fat Tuesday is not for another few days??Funny you should say that .
It was mardi-Gras here last night
However I definately was not there.
Leather undies chaff way too much and sequined undies prickle.
#15
B
Beau
Heck the parades start a month in advance here.
B
Beau
Fat Tuesday is not for another few days??
Heck the parades start a month in advance here.
#16
B
Beau
B
Beau
You must be in Mobile.Funny you should say that .
It was mardi-Gras here last night
However I definately was not there.
Leather undies chaff way too much and sequined undies prickle.
#17
B
bertsmobile1
B
bertsmobile1
For fear of getting way off topic countries other than the USA have Mardi Gras
https://www.theguardian.com/australia-news/gallery/2019/mar/02/sydney-gay-and-lesbian-mardi-gras-in-pictures
https://www.theguardian.com/australia-news/gallery/2019/mar/02/sydney-gay-and-lesbian-mardi-gras-in-pictures
#18
B
Beau
B
Beau
So I checked the valve clearance and both sides were very tight, as in no clearance. Adjusted both sides to specs and tried turning the engine over. I've got it to pop on nearly every cycle but wouldn't take off on its own. So, I pulled the plugs again and still have good spark on both sides. However, looking at the plugs its clear the right cylinder is not firing. The left plug is clearly burning but the right plug is clean as a whistle and looks as brand new as when I put it in a couple of days ago. Both valves appear to be moving freely on both sides.
Attaching some images
Attaching some images
Attachments
#19
B
Beau
B
Beau
Also, in terms of noise I haven't heard anything that sounds un-normal (other than the lack of a running engine). When turning the flywheel I hear the typical whoosh and gurgle coming out of the carburetor and air pushing out of the spark plug holes when the plugs are pulled. Thats about it. Starting to think it may be electrical because of the lack of fire on the right cylinder.
#20
B
bertsmobile1
B
bertsmobile1
Before you go any further I would whip out those guide plates clean them up & wack some paint on them.
I gather it gets a tad humid around your place with real cold nights & heavy dew.
SO some background might be good.
When did the engine last run ?
IS the loss of compression sudden or has it been getting harder to start for a while.
Also did you do the compression as per the manual.
You said you have worked on other engines so I hope that meas to rotated each cylinder to TDC compression before taking the readings & making the adjustments.
As for the plug, no colour is better than black.
If the engine is not running you will get no deposits on the plug.
If you have been cranking it for a while & it has not fired then the plug should be wet with fuel.
If not check the fuel cut off solenoid on the bottom of the carburettor.
If you get that much water in your rocker cavity chances are there is water in the solenoid & it has corroded closed.
I gather it gets a tad humid around your place with real cold nights & heavy dew.
SO some background might be good.
When did the engine last run ?
IS the loss of compression sudden or has it been getting harder to start for a while.
Also did you do the compression as per the manual.
You said you have worked on other engines so I hope that meas to rotated each cylinder to TDC compression before taking the readings & making the adjustments.
As for the plug, no colour is better than black.
If the engine is not running you will get no deposits on the plug.
If you have been cranking it for a while & it has not fired then the plug should be wet with fuel.
If not check the fuel cut off solenoid on the bottom of the carburettor.
If you get that much water in your rocker cavity chances are there is water in the solenoid & it has corroded closed.
#21
B
Beau
Put everything back together so I’m gonna hold off on cleaning up the guide plates until I figure out if I have to break this thing down or not.
I adjusted the valve clearance at TDC yes, and triple checked them. Adjusted to factory specs. When I checked the compression I simply put my compression gauge and cranked the engine over a few times. I did this multiple times both sides. Not sure what or if there is any other method. But again it wasn’t a leak down test, don’t have the equipment for that.
Also pulled the carburetor and cleaned it, plus drained the tanks and cleaned them as well. The carb has fuel in it as it drains out of the bottom from the drain screw.
Both plugs are new. The left cylinder is showing light blackening from cranking the engine. The right has zero discoloration and I can smell fuel on it.
This motor was given to me and has been sitting for quite sometime and supposedly was running good but I don’t really know that for sure.
If I’m getting drastically different compression readings between the two cylinders, with any engine I’ve ever dealt with that would indicate something like a cylinder that needs to be rebuilt. Why would this engine be any different?
Thanks
B
Beau
Before you go any further I would whip out those guide plates clean them up & wack some paint on them.
I gather it gets a tad humid around your place with real cold nights & heavy dew.
SO some background might be good.
When did the engine last run ?
IS the loss of compression sudden or has it been getting harder to start for a while.
Also did you do the compression as per the manual.
You said you have worked on other engines so I hope that meas to rotated each cylinder to TDC compression before taking the readings & making the adjustments.
As for the plug, no colour is better than black.
If the engine is not running you will get no deposits on the plug.
If you have been cranking it for a while & it has not fired then the plug should be wet with fuel.
If not check the fuel cut off solenoid on the bottom of the carburettor.
If you get that much water in your rocker cavity chances are there is water in the solenoid & it has corroded closed.
Put everything back together so I’m gonna hold off on cleaning up the guide plates until I figure out if I have to break this thing down or not.
I adjusted the valve clearance at TDC yes, and triple checked them. Adjusted to factory specs. When I checked the compression I simply put my compression gauge and cranked the engine over a few times. I did this multiple times both sides. Not sure what or if there is any other method. But again it wasn’t a leak down test, don’t have the equipment for that.
Also pulled the carburetor and cleaned it, plus drained the tanks and cleaned them as well. The carb has fuel in it as it drains out of the bottom from the drain screw.
Both plugs are new. The left cylinder is showing light blackening from cranking the engine. The right has zero discoloration and I can smell fuel on it.
This motor was given to me and has been sitting for quite sometime and supposedly was running good but I don’t really know that for sure.
If I’m getting drastically different compression readings between the two cylinders, with any engine I’ve ever dealt with that would indicate something like a cylinder that needs to be rebuilt. Why would this engine be any different?
Thanks
#22
Scrubcadet10
Scrubcadet10
Usually on engines with ACR's , you won't get an accurate compression reading, why? Because the compression release is doing it's job.
If you had a way to spin the engine at normal running RPM it would be accurat e.
I believe with compression releases it usually drops the pressure to about 80 or 90 pounds on most small engines.
https://www.youtube.com/watch?v=jc3j4ShE-tk
If you had a way to spin the engine at normal running RPM it would be accurat e.
I believe with compression releases it usually drops the pressure to about 80 or 90 pounds on most small engines.
https://www.youtube.com/watch?v=jc3j4ShE-tk
#23
B
Beau
Thanks thats a good video. Think I'll pick up a tester and do a leak down test.
What is throwing me on the compression is I assumed that the ACR would affect both cylinders but it would make sense that its only one cylinder.
B
Beau
Usually on engines with ACR's , you won't get an accurate compression reading, why? Because the compression release is doing it's job.
If you had a way to spin the engine at normal running RPM it would be accurat e.
I believe with compression releases it usually drops the pressure to about 80 or 90 pounds on most small engines.
https://www.youtube.com/watch?v=jc3j4ShE-tk
Thanks thats a good video. Think I'll pick up a tester and do a leak down test.
What is throwing me on the compression is I assumed that the ACR would affect both cylinders but it would make sense that its only one cylinder.
#24
Boudreaux In Eunice La.
Boudreaux In Eunice La.
Beau Yes do a leak down test, that will tell you for sure the rings ore leaking VALVES..... Where you at down here in Mardi Gras country Mon Ami ~!~! ??????
#25
Boudreaux In Eunice La.
Fish we been kicking it up in Eunice since Friday night down town, Maybe even before that LOL...........Schools close down for a few days too.... Stores close some banks close....... Cest La Vie..........
Boudreaux In Eunice La.
Fat Tuesday is not for another few days??
Fish we been kicking it up in Eunice since Friday night down town, Maybe even before that LOL...........Schools close down for a few days too.... Stores close some banks close....... Cest La Vie..........
#26
B
Beau
Boudreaux I’m planning on it. Just gotta get a leak down kit.
I’m over in Madisonville but wish I was in your neck of the woods. I’m originally from Gran Anse. But part of my family was from around Eunice. Hope you passed a good Mardi Gras!
B
Beau
Beau Yes do a leak down test, that will tell you for sure the rings ore leaking VALVES..... Where you at down here in Mardi Gras country Mon Ami ~!~! ??????
Boudreaux I’m planning on it. Just gotta get a leak down kit.
I’m over in Madisonville but wish I was in your neck of the woods. I’m originally from Gran Anse. But part of my family was from around Eunice. Hope you passed a good Mardi Gras!
#27
B
Beau
B
Beau
Ok, so I finally got around to performing a leak down test on the engine.
On the right cylinder with both valves in the closed position at tdc I've got heavy air flow from the exhaust so obviously the exhaust valve is not seating properly. If I block off the exhaust I've got some air flow from the crank case and the gauge drops to between 45 and 50%.
On the left cylinder with both valves in the closed position at tdc I've got no air flow from valves. I do have some air flow from the crank case and the gauge drops between 40 and 45%.
I'm not sure whats normal for air flow around the pistons to the crankcase but more than likely less than what I'm seeing/hearing but the fact that its fairly even on both sides to me would seem like normal wear. Granted, this leak down kit is from Harbor Freight so not sure how accurate it is anyway. But again I do think there is obvious wear in the cylinders but seems as though engine should run even with that wear.
The problem appears to be with the exhaust valve on the right cylinder I suspected something was up with that cylinder to start with.
The valve stem does not appear to be bent and I don't hear any unusual noise when turning the engine over. But aside from pulling the heads to take a look at the valve any advice here would be appreciated.
Thanks
On the right cylinder with both valves in the closed position at tdc I've got heavy air flow from the exhaust so obviously the exhaust valve is not seating properly. If I block off the exhaust I've got some air flow from the crank case and the gauge drops to between 45 and 50%.
On the left cylinder with both valves in the closed position at tdc I've got no air flow from valves. I do have some air flow from the crank case and the gauge drops between 40 and 45%.
I'm not sure whats normal for air flow around the pistons to the crankcase but more than likely less than what I'm seeing/hearing but the fact that its fairly even on both sides to me would seem like normal wear. Granted, this leak down kit is from Harbor Freight so not sure how accurate it is anyway. But again I do think there is obvious wear in the cylinders but seems as though engine should run even with that wear.
The problem appears to be with the exhaust valve on the right cylinder I suspected something was up with that cylinder to start with.
The valve stem does not appear to be bent and I don't hear any unusual noise when turning the engine over. But aside from pulling the heads to take a look at the valve any advice here would be appreciated.
Thanks
#28
cpurvis
cpurvis
Make sure when you do your tests that you have clearance between the valve stem and rocker arm. (To make sure the cam isn't holding a valve open.)
The air you hear going into the crankcase is going past the rings. This is a sign of wear. How many hours on the engine? Has the air filter been properly maintained?
The air you hear going into the exhaust (or intake) is air leaking past a valve. I can't speak for the FH601V, but the manual for the FR651V thru FR730V calls for "cleaning the combustion chamber, check and adjust valve clearances, and clean and lap valve seating surfaces" 300 hours. I can just about guarantee that 9 out of 10 owners are NOT going to do that and if they do, are smart enough to not do it in the order specified.
It might be that the 300 hour cleaning is to prevent the problem you're having. But it wouldn't have helped the rings.
The air you hear going into the crankcase is going past the rings. This is a sign of wear. How many hours on the engine? Has the air filter been properly maintained?
The air you hear going into the exhaust (or intake) is air leaking past a valve. I can't speak for the FH601V, but the manual for the FR651V thru FR730V calls for "cleaning the combustion chamber, check and adjust valve clearances, and clean and lap valve seating surfaces" 300 hours. I can just about guarantee that 9 out of 10 owners are NOT going to do that and if they do, are smart enough to not do it in the order specified.
It might be that the 300 hour cleaning is to prevent the problem you're having. But it wouldn't have helped the rings.
#29
B
Beau
Thanks. Yes I had clearance between valve stems and rocker arms and understand why the air is moving through the various parts.
Have no idea how many hours are on the engine but I can bet the valves and seats have never been cleaned or lapped. I guess I should pull the head and take a look at the valves.
B
Beau
Make sure when you do your tests that you have clearance between the valve stem and rocker arm. (To make sure the cam isn't holding a valve open.)
The air you hear going into the crankcase is going past the rings. This is a sign of wear. How many hours on the engine? Has the air filter been properly maintained?
The air you hear going into the exhaust (or intake) is air leaking past a valve. I can't speak for the FH601V, but the manual for the FR651V thru FR730V calls for "cleaning the combustion chamber, check and adjust valve clearances, and clean and lap valve seating surfaces" 300 hours. I can just about guarantee that 9 out of 10 owners are NOT going to do that and if they do, are smart enough to not do it in the order specified.
It might be that the 300 hour cleaning is to prevent the problem you're having. But it wouldn't have helped the rings.
Thanks. Yes I had clearance between valve stems and rocker arms and understand why the air is moving through the various parts.
Have no idea how many hours are on the engine but I can bet the valves and seats have never been cleaned or lapped. I guess I should pull the head and take a look at the valves.
#30
B
bertsmobile1
Well down here head gaskets are only $ 13 each so why not.
Push rof engnes are so easy to do head jobs on it is almost a crime not to.
B
bertsmobile1
Thanks. Yes I had clearance between valve stems and rocker arms and understand why the air is moving through the various parts.
Have no idea how many hours are on the engine but I can bet the valves and seats have never been cleaned or lapped. I guess I should pull the head and take a look at the valves.
Well down here head gaskets are only $ 13 each so why not.
Push rof engnes are so easy to do head jobs on it is almost a crime not to.
#31
B
Beau
Beat you to it. went ahead and pulled the head and here's some images of what I found. Not sure what a burnt valve is supposed to look like but since the exhaust valve is completely out of round, and i can see my flashlight all the way around it from the exhaust port when its in the valve seat, I guess this one is.
My question now is what should I do? Replace exhaust and intake valves on both cylinders and have the valve seats lapped? Since I'm not sure of the hours on the motor I hate to get into rebuilding the whole thing. Should I just do the valve and head work and see what happens?
Thanks
B
Beau
Well down here head gaskets are only $ 13 each so why not.
Push rof engnes are so easy to do head jobs on it is almost a crime not to.
Beat you to it. went ahead and pulled the head and here's some images of what I found. Not sure what a burnt valve is supposed to look like but since the exhaust valve is completely out of round, and i can see my flashlight all the way around it from the exhaust port when its in the valve seat, I guess this one is.
My question now is what should I do? Replace exhaust and intake valves on both cylinders and have the valve seats lapped? Since I'm not sure of the hours on the motor I hate to get into rebuilding the whole thing. Should I just do the valve and head work and see what happens?
Thanks
Attachments
#32
B
bertsmobile1
B
bertsmobile1
Yep that is exactly what a burned exhaust valve looks like.
Eventually it would make a V shaped crack in the middle of that flat spot.
It will need to be replaced.
If you have access to the tools, it is not a hard job.
If not take it to a mower repair shop, not a glass fronted mower retailer.
Most shops will replace the valve, clean the head & lap them in for a reasonable amount.
I charge 1/2 hour $ 30 + parts.
Not sure if yours has a seal on the inlet only or both inlet & exhaust.
If you want to do it yourself, buy a long 14mm x 1.25 bolt & a couple of nuts.
Thread the bolt through the spark plug hole & lock it with a nut either side
Then use this to hold the head in a vice while you attack the valves.
From the look of it something has dropped into the cylinder then got stuck under the head of the exhaust valve holding it open just a touch.
The actual damage looks exactly like what happens when a spark plug helicoil is used & the fitter loose the tang into the engine.
The next step is to get a new valve and feel how it fits in the guide.
It should rotate freely but not rock from side to side.
O small alloy heads like this one it is better to fit a sleeve in the guide than to replace the guide but either way that has to happen before the seat gets recut as the seat has to be true to the guide or the valve closes ( or rather doen't close ) at an angle and yo are back where you started.
Before you get too far, check the price of a new head.
Often the difference between a new head & a head job is marginal.
Eventually it would make a V shaped crack in the middle of that flat spot.
It will need to be replaced.
If you have access to the tools, it is not a hard job.
If not take it to a mower repair shop, not a glass fronted mower retailer.
Most shops will replace the valve, clean the head & lap them in for a reasonable amount.
I charge 1/2 hour $ 30 + parts.
Not sure if yours has a seal on the inlet only or both inlet & exhaust.
If you want to do it yourself, buy a long 14mm x 1.25 bolt & a couple of nuts.
Thread the bolt through the spark plug hole & lock it with a nut either side
Then use this to hold the head in a vice while you attack the valves.
From the look of it something has dropped into the cylinder then got stuck under the head of the exhaust valve holding it open just a touch.
The actual damage looks exactly like what happens when a spark plug helicoil is used & the fitter loose the tang into the engine.
The next step is to get a new valve and feel how it fits in the guide.
It should rotate freely but not rock from side to side.
O small alloy heads like this one it is better to fit a sleeve in the guide than to replace the guide but either way that has to happen before the seat gets recut as the seat has to be true to the guide or the valve closes ( or rather doen't close ) at an angle and yo are back where you started.
Before you get too far, check the price of a new head.
Often the difference between a new head & a head job is marginal.
#33
B
Beau
Thanks. Good advice on new vs rework. Around here small engine guys charge like attorneys so may end up being cheaper to go new.
B
Beau
Yep that is exactly what a burned exhaust valve looks like.
Eventually it would make a V shaped crack in the middle of that flat spot.
It will need to be replaced.
If you have access to the tools, it is not a hard job.
If not take it to a mower repair shop, not a glass fronted mower retailer.
Most shops will replace the valve, clean the head & lap them in for a reasonable amount.
I charge 1/2 hour $ 30 + parts.
Not sure if yours has a seal on the inlet only or both inlet & exhaust.
If you want to do it yourself, buy a long 14mm x 1.25 bolt & a couple of nuts.
Thread the bolt through the spark plug hole & lock it with a nut either side
Then use this to hold the head in a vice while you attack the valves.
From the look of it something has dropped into the cylinder then got stuck under the head of the exhaust valve holding it open just a touch.
The actual damage looks exactly like what happens when a spark plug helicoil is used & the fitter loose the tang into the engine.
The next step is to get a new valve and feel how it fits in the guide.
It should rotate freely but not rock from side to side.
O small alloy heads like this one it is better to fit a sleeve in the guide than to replace the guide but either way that has to happen before the seat gets recut as the seat has to be true to the guide or the valve closes ( or rather doen't close ) at an angle and yo are back where you started.
Before you get too far, check the price of a new head.
Often the difference between a new head & a head job is marginal.
Thanks. Good advice on new vs rework. Around here small engine guys charge like attorneys so may end up being cheaper to go new.
#34
B
bertsmobile1
Check the repair only workshops and in particular owner operated ones.
Glass fronts generally just use the workshop to produce massive repair bills to convince customers to replace their mower.
Down here the independent shop up the road charges $ 90/hr and adsorbs sundry items like small bolts & R clips
In town the biggest shop charges $ 120 / hr and adds items like "cleaning products, workshop towels, solvents & adheasives" and charge for every nut bolt & washer.
The Stihl shop charges $ 150 / hr
The JD shop charges set fees so harder to work out their hourly charge but they are charging $ 375 for a basic service on a running machine ( I charge $ 120 ) and the scheduled rate is 2 hours.
Remember these are in $ Aus about 70% of the US $ .
B
bertsmobile1
Thanks. Good advice on new vs rework. Around here small engine guys charge like attorneys so may end up being cheaper to go new.
Check the repair only workshops and in particular owner operated ones.
Glass fronts generally just use the workshop to produce massive repair bills to convince customers to replace their mower.
Down here the independent shop up the road charges $ 90/hr and adsorbs sundry items like small bolts & R clips
In town the biggest shop charges $ 120 / hr and adds items like "cleaning products, workshop towels, solvents & adheasives" and charge for every nut bolt & washer.
The Stihl shop charges $ 150 / hr
The JD shop charges set fees so harder to work out their hourly charge but they are charging $ 375 for a basic service on a running machine ( I charge $ 120 ) and the scheduled rate is 2 hours.
Remember these are in $ Aus about 70% of the US $ .