You are using an out of date browser. It may not display this or other websites correctly.
You should upgrade or use an alternative browser.
You should upgrade or use an alternative browser.
Export thread
Riding Mower Engine Overheating
#1
R
Rick'sToro8-32
R
Rick'sToro8-32
I have a Brigg's and Stratton 8 HP on my 30 year old Toro 8-32 riding mower.
It has been overheating after about 45 minutes and before I am finished mowing, and konking out. When it cools down I start it back up and finish mowing.
Does anyone have any idea what might be causing this situation?
Thank you.
It has been overheating after about 45 minutes and before I am finished mowing, and konking out. When it cools down I start it back up and finish mowing.
Does anyone have any idea what might be causing this situation?
Thank you.
#2
I
ILENGINE
I
ILENGINE
Give us a model number information so we can see what engine you are attempting to repair. When the engine quits do you still have spark. Are you sure there isn't a mouse nest in the engine causing overheating.
#3
R
Rick'sToro8-32
R
Rick'sToro8-32
Thanks.
B & S 8HP at 3600 r/min
Synchro-Balanced
Model: 191707
Type: 2161-01
Code: 87042712
It just did it again, I popped out the spark plug and turned it over and could see I am getting good spark. There is no sign of debris under the cowling, I actually put a new electronic ignition in it not long ago, it was clean then. I don't think there is a nest or grass there.
I'm not sure what a vapor lock in the gas line is really, but that is what has popped into my mind as I consider this.
This problem has been going on for the past couple years, it is to the point where I need to fix it now.
Thank you.
B & S 8HP at 3600 r/min
Synchro-Balanced
Model: 191707
Type: 2161-01
Code: 87042712
It just did it again, I popped out the spark plug and turned it over and could see I am getting good spark. There is no sign of debris under the cowling, I actually put a new electronic ignition in it not long ago, it was clean then. I don't think there is a nest or grass there.
I'm not sure what a vapor lock in the gas line is really, but that is what has popped into my mind as I consider this.
This problem has been going on for the past couple years, it is to the point where I need to fix it now.
Thank you.
#4
G
gainestruk
G
gainestruk
Next time it does it spray a little starting fluid or pour a thimble full of gas down throat of carburetor to see if it's a fuel delivery problem, if it starts its something in fuel system, just be very careful engine is hot !
Speaking of hot what is it doing other than shutting off to make you think it's overheated ?
Speaking of hot what is it doing other than shutting off to make you think it's overheated ?
#5
R
Rick'sToro8-32
R
Rick'sToro8-32
It only does this on hot summer days for one thing. In the spring and fall when air temps are cold there is no problem.
Also, when I was young I worked at a cemetery and drove a commercial Ferris mower. It was known for getting hot, and the temp gauge agreed, and quitting and then after it cooled down it would run again--just like my little mower.
When an engine overheats it has a certain smell (like the Ferris), and you can almost feel that the engine is too hot from the heat that radiates off the engine. That's how mine is when it quits it just smells too hot and when you pull up the seat it is noticably hotter than it is when it is running fine.
Also, when I was young I worked at a cemetery and drove a commercial Ferris mower. It was known for getting hot, and the temp gauge agreed, and quitting and then after it cooled down it would run again--just like my little mower.
When an engine overheats it has a certain smell (like the Ferris), and you can almost feel that the engine is too hot from the heat that radiates off the engine. That's how mine is when it quits it just smells too hot and when you pull up the seat it is noticably hotter than it is when it is running fine.
#6
S
SeniorCitizen
S
SeniorCitizen
Pull the shroud and look for blockage rather than just thinking it's clean.
I had a mouse build a nest over night while 3 cats slept close to the food bowl within 20 feet. I could see it on top of the flywheel when checking the oil level but they aren't always visible. Cleaned it out and same thing happened the next night. Cleaned it again and sent 3 cats to cat heaven. English Blue blood lines and I'm sure some have won blue ribbons at cat shows somewhere but worthless as mousers.
I had a mouse build a nest over night while 3 cats slept close to the food bowl within 20 feet. I could see it on top of the flywheel when checking the oil level but they aren't always visible. Cleaned it out and same thing happened the next night. Cleaned it again and sent 3 cats to cat heaven. English Blue blood lines and I'm sure some have won blue ribbons at cat shows somewhere but worthless as mousers.
#7
G
gainestruk
G
gainestruk
If engine is running lean that can cause heat, make sure your air filter is clean.
Hopefully someone else can think of something and jump in.
Hopefully someone else can think of something and jump in.
#8
S
SeniorCitizen
S
SeniorCitizen
I'm not up to date on engines that a timing light can't be used on but it seems like if a flywheel key was sheared or partially sheared it would advance the timing which would possibly cause over heating.
To check timing on a mower engine i always held my thumb on the plug hole and watched the spark. If my thumb is blown from the hole at the same instant I see spark it be close enough.
To check timing on a mower engine i always held my thumb on the plug hole and watched the spark. If my thumb is blown from the hole at the same instant I see spark it be close enough.
#9
R
Rick'sToro8-32
R
Rick'sToro8-32
The comment on timing makes sense. And, when I had the spark plug out today it was very clean and light/white colored, I think that means it is running lean, so maybe that is an issue.
#10
M
motoman
M
motoman
A person can not tell how hot something is. It requires a gauge which is not expensive. If you can obtain expected engine temperatures from some source (not likely) you can use an infra red gun or a heat probe furnished with a $50 DVM to take readings around the engine...cylinder fins, head. Or you can buy some temperature crayons at a welding supply house. But the best for AC engines is an oil temp gauge because as the oil goes so goes the engine. I start my fan on my oil cooler When oil temp climbs to 280F- which is very often when mowing here in summer. And using the craftsman 3 bin baggers will quickly push the oil temp to 300F as the damp grass weight increases. The ignition modules on the Intek I have sits on thick cast iron seats which helps keep the modules below failure range of 180F-240F. But I would imagine heat is more of factor on lawnmowers with smaller metal mass.(almost done)
You can easily find and mark true TDC and put a ref mark on your machine. Then hook up an inductive pickup style auto timing light. I did this . You may have to work in a darkened area to see the weak strobe the ignition module puts out. Mine was a faint reddish flash. But it is probably easier to check flywheel key first. Finding TDC is probably not worth the effort if you can avoid it .
You can easily find and mark true TDC and put a ref mark on your machine. Then hook up an inductive pickup style auto timing light. I did this . You may have to work in a darkened area to see the weak strobe the ignition module puts out. Mine was a faint reddish flash. But it is probably easier to check flywheel key first. Finding TDC is probably not worth the effort if you can avoid it .
#11
R
Rick'sToro8-32
R
Rick'sToro8-32
Thanks very much for all of the posts! :smile:
If I am hearing things correctly it seems as though the consensus is that my mower is konking out after about 40 minutes of run time because of a timing issue.
It occurrs to me that this mower has never had a valve job. It think poorly seated valves can mess up the timing. I wonder if this could be the 'cause' of the problem.
Also, in the back of my mind, I think I remember something about a vapor lock in the gas line that creates a situation like mine from a mower when I used to work at a local cemetery. It seems like we had a mower that would run until it heated up and then konk out and then run again when it cooled down. I think I remember the mechanic there saying it was a vapor lock or something like. Does anyone know anything about this?
That is the 'symptom' of my mower: simply put, it runs great until it heats up then it konks out--and when it cools down it runs great again until it heats up and konks out again.
If I am hearing things correctly it seems as though the consensus is that my mower is konking out after about 40 minutes of run time because of a timing issue.
It occurrs to me that this mower has never had a valve job. It think poorly seated valves can mess up the timing. I wonder if this could be the 'cause' of the problem.
Also, in the back of my mind, I think I remember something about a vapor lock in the gas line that creates a situation like mine from a mower when I used to work at a local cemetery. It seems like we had a mower that would run until it heated up and then konk out and then run again when it cooled down. I think I remember the mechanic there saying it was a vapor lock or something like. Does anyone know anything about this?
That is the 'symptom' of my mower: simply put, it runs great until it heats up then it konks out--and when it cools down it runs great again until it heats up and konks out again.
#12
G
gainestruk
G
gainestruk
I have seen fuel get too hot and bubble in filter, you could add some line and route it away from engine and also move filter closer to the tank.
Is this a flat head Briggs ?
If so pull head off and clean carbon and look at valves.
Is this a flat head Briggs ?
If so pull head off and clean carbon and look at valves.
#13
M
Mad Mackie
M
Mad Mackie
Carbon buildup on the piston top and combustion chamber will get hotter as the engine is running. It will get hot enough that it will start burning the incoming air/fuel mixture before the spark plug fires. This is caller detonation, and when it occurs, a more rapid than normal burning of the still compressing air/fuel mixture occurs to the extent of hammering the piston and slowing it down while still in the compression stroke. Detonation will cause power loss and overheating to the point of engine shutdown. The incoming air/fuel mixture with the fuel in an atomized state, when exposed to the higher than normal temperature, vaporizes and no longer remains in an air/fuel atomized mixture which is necessary for an internal combustion engine to continue running.
#14
R
Rick'sToro8-32
Thanks very much! This sounds right to me!
I have to work the next five days 12 hours per day, but now I am very anxious to pick up a new head gasket and pop the head off next week.
It is true that after things heat up, I do start to loose power before the engine finally shuts down. I'll bet this is exactly the root cause of my problem.
I'll report back next week after I work on the mower.
Thanks again very much Mad Mackie!! :thumbsup:
R
Rick'sToro8-32
Carbon buildup on the piston top and combustion chamber will get hotter as the engine is running. It will get hot enough that it will start burning the incoming air/fuel mixture before the spark plug fires. This is caller detonation, and when it occurs, a more rapid than normal burning of the still compressing air/fuel mixture occurs to the extent of hammering the piston and slowing it down while still in the compression stroke. Detonation will cause power loss and overheating to the point of engine shutdown. The incoming air/fuel mixture with the fuel in an atomized state, when exposed to the higher than normal temperature, vaporizes and no longer remains in an air/fuel atomized mixture which is necessary for an internal combustion engine to continue running.
Thanks very much! This sounds right to me!
I have to work the next five days 12 hours per day, but now I am very anxious to pick up a new head gasket and pop the head off next week.
It is true that after things heat up, I do start to loose power before the engine finally shuts down. I'll bet this is exactly the root cause of my problem.
I'll report back next week after I work on the mower.
Thanks again very much Mad Mackie!! :thumbsup:
#15
M
motoman
M
motoman
So detonation occurs in lowly air cooled tractor engines?? No one I have read in this forum has ever suggested this. Are these engines so loud you cannot hear the detonation? Have never seen a tractor piston melted in the classic detonation manner. Never heard of a knock sensor on these engines. Just saying...
#16
M
Mad Mackie
Why does every small engine manufacturer recommend removal of the cylinder head(s) at specified hours of operation to remove carbon buildup?
I have never heard actual detonation occurring in a small engine, however I have seen the resulting internal damage. During operation when an unexpected deterioration of performance happens, detonation sometimes is the cause. Many small engines don't get run long enough for the carbon buildup to get hot enough to cause a problem, but some do. An engine decarb is more involved than other routine engine maintenance and as result doesn't get done very often.
Carbon buildup is more of a concern with L head engines where the piston at TDC comes very close to the cylinder head. On some engines, Onan twins in particular, when the piston makes contact with the hard carbon buildup, the engine performance has already deteriorated and now serious internal engine damage starts. Overheating and broken connecting rods are the nasty results, sometimes the broken connecting rod swings around and pokes holes in the crankcase destroying the engine.
I don't know of any small engines that have a knock sensor, the ability to change spark timing would be needed all of which would increase the cost of the engine substantially. Engines with DFI or EFI will already have a computer to control fuel management and would be easier to incorporate a knock sensor and the ability to vary spark timing. Retired now although I still do limited equipment servicing, I stay away from DFI and EFI equipped engines.
All small aircooled engines be they 2 stroke or 4 stroke consume oil during operation, some of the consumed oil ends up in the combustion chamber as carbon buildup which in time becomes a hard crystalline appearing substance requiring mechanical removal.
The unburned incoming air/fuel mixture contributes somewhat to engine cooling, but when it starts burning before the spark plug fires, then it's contribution to engine cooling is greatly reduced which results in increased combustion chamber temperatures and decreased engine performance.
Having been a military flight engineer on large piston engine powered aircraft, I have experienced detonation, not a pleasant experience as it frequently results in engine failure at the least opportune times like takeoffs at high ambient temperatures.
M
Mad Mackie
So detonation occurs in lowly air cooled tractor engines?? No one I have read in this forum has ever suggested this. Are these engines so loud you cannot hear the detonation? Have never seen a tractor piston melted in the classic detonation manner. Never heard of a knock sensor on these engines. Just saying...
Why does every small engine manufacturer recommend removal of the cylinder head(s) at specified hours of operation to remove carbon buildup?
I have never heard actual detonation occurring in a small engine, however I have seen the resulting internal damage. During operation when an unexpected deterioration of performance happens, detonation sometimes is the cause. Many small engines don't get run long enough for the carbon buildup to get hot enough to cause a problem, but some do. An engine decarb is more involved than other routine engine maintenance and as result doesn't get done very often.
Carbon buildup is more of a concern with L head engines where the piston at TDC comes very close to the cylinder head. On some engines, Onan twins in particular, when the piston makes contact with the hard carbon buildup, the engine performance has already deteriorated and now serious internal engine damage starts. Overheating and broken connecting rods are the nasty results, sometimes the broken connecting rod swings around and pokes holes in the crankcase destroying the engine.
I don't know of any small engines that have a knock sensor, the ability to change spark timing would be needed all of which would increase the cost of the engine substantially. Engines with DFI or EFI will already have a computer to control fuel management and would be easier to incorporate a knock sensor and the ability to vary spark timing. Retired now although I still do limited equipment servicing, I stay away from DFI and EFI equipped engines.
All small aircooled engines be they 2 stroke or 4 stroke consume oil during operation, some of the consumed oil ends up in the combustion chamber as carbon buildup which in time becomes a hard crystalline appearing substance requiring mechanical removal.
The unburned incoming air/fuel mixture contributes somewhat to engine cooling, but when it starts burning before the spark plug fires, then it's contribution to engine cooling is greatly reduced which results in increased combustion chamber temperatures and decreased engine performance.
Having been a military flight engineer on large piston engine powered aircraft, I have experienced detonation, not a pleasant experience as it frequently results in engine failure at the least opportune times like takeoffs at high ambient temperatures.
#17
M
motoman
M
motoman
Well, I believe the inherent design of the low rpm, slow moving air cooled lawnmower engine is to operate in a high heat condition. A condition not far from engine damage. Especially for many owners who see these machines as kitchen appliances. I repeat you cannot know how hot the engine is without measurement . Apparently earlier machines had oil coolers and warning devices on them which have been discountinued (IMO) for lack of attention by owners and perhaps by marketing priorities (buy another). Yes, I am saying this from my sample of ONE machine and therefore cannot offer conclusive evidence. Keep 'em running as cool as possible -it ain't easy.
#18
KrashnKraka
Sound info in that post.
All being equal the engine may require oil cooler help. I have a new engine
I am experimenting with in such a way - better than 40Celcius ambients on
summer days.
KrashnKraka
A person can not tell how hot something is. It requires a gauge which is not expensive. If you can obtain expected engine temperatures from some source (not likely) you can use an infra red gun or a heat probe furnished with a $50 DVM to take readings around the engine...cylinder fins, head. Or you can buy some temperature crayons at a welding supply house. But the best for AC engines is an oil temp gauge because as the oil goes so goes the engine. I start my fan on my oil cooler When oil temp climbs to 280F- which is very often when mowing here in summer. And using the craftsman 3 bin baggers will quickly push the oil temp to 300F as the damp grass weight increases. The ignition modules on the Intek I have sits on thick cast iron seats which helps keep the modules below failure range of 180F-240F. But I would imagine heat is more of factor on lawnmowers with smaller metal mass.(almost done)
You can easily find and mark true TDC and put a ref mark on your machine. Then hook up an inductive pickup style auto timing light. I did this . You may have to work in a darkened area to see the weak strobe the ignition module puts out. Mine was a faint reddish flash. But it is probably easier to check flywheel key first. Finding TDC is probably not worth the effort if you can avoid it .
Sound info in that post.
All being equal the engine may require oil cooler help. I have a new engine
I am experimenting with in such a way - better than 40Celcius ambients on
summer days.
#19
M
motoman
M
motoman
Here it only takes about 85F ambient and full grass hoppers on a slight incline to drive oil temp to 280-300F. Even with the oil cooler and fan on it will slowly climb to 280F. In the shade with the fan running and hood up,idling I can pull 50F of heat out of the oil in several minutes rest. (Craftsman 48 with Intek 24 V)
#20
R
Rick'sToro8-32
R
Rick'sToro8-32
I picked up a head gasket the other day.
Is anyone else agreeing that my 30 year old mower could be carboned up in the head/piston area and this could be the problem?
Is anyone else agreeing that my 30 year old mower could be carboned up in the head/piston area and this could be the problem?
#21
KrashnKraka
Doesn't read as such to me, a lot of variables in 30 years of time.
Like only 40 hours of operation 'cos each year it is used the engine
appears to overheat so back in locker it goes till next year, year in
year out.
:laugh:
Srsly, other symptoms would have appeared long before serious
carbon buildup. You only report one consistent symptom.
Buuuuut... as a test you can try getting the unit hot, at night.
In the dark you will see loose burning carbon particles flying out of
the exhaust. If in numbers it is best you strip and decoke.
I still don't believe that is going to fix your problem - it may just prove
another symptom.
My money is on a timing issue, or wrong plugs.
-- flipping cards an ' readin' sign
KrashnKraka
I picked up a head gasket the other day.
Is anyone else agreeing that my 30 year old mower could be carboned up in the head/piston area and this could be the problem?
Doesn't read as such to me, a lot of variables in 30 years of time.
Like only 40 hours of operation 'cos each year it is used the engine
appears to overheat so back in locker it goes till next year, year in
year out.
:laugh:
Srsly, other symptoms would have appeared long before serious
carbon buildup. You only report one consistent symptom.
Buuuuut... as a test you can try getting the unit hot, at night.
In the dark you will see loose burning carbon particles flying out of
the exhaust. If in numbers it is best you strip and decoke.
I still don't believe that is going to fix your problem - it may just prove
another symptom.
My money is on a timing issue, or wrong plugs.
-- flipping cards an ' readin' sign
#22
R
Rick'sToro8-32
R
Rick'sToro8-32
"My money is on a timing issue, or wrong plugs."
Appreciate it!! :smile:
When I get some time to work on it this week we will find out. I could see the chuck key being an issue too as mentioned above. I do get a slight backfire when I shut it down. It's never had a valve job in 30 yeears for that matter.
Thanks again!
PS Just to be clear this issue started about 2 years ago. You are right though, since then it has been back in the shed at the end of the mowing season.:ashamed:
Appreciate it!! :smile:
When I get some time to work on it this week we will find out. I could see the chuck key being an issue too as mentioned above. I do get a slight backfire when I shut it down. It's never had a valve job in 30 yeears for that matter.
Thanks again!
PS Just to be clear this issue started about 2 years ago. You are right though, since then it has been back in the shed at the end of the mowing season.:ashamed:
#23
KrashnKraka
This is all good info in the thread... you should appreciate in a workshop environ it would
take some less time to find the problem than write up a post on what the problem may be.
For example when "timing issues" are written? That could prove to be anything from a
dislodged crankshaft key to a camshaft cog worn to the bejaysus. Better to keep it simple
and work on your feedback.
It aint a competition, with your posts being of the most value here, not the assorted
thoughts of those working from experience or logic, or both.
At the end of the day you will be mowing grass, cool.
That outcome should be the only priority.
Cheers...
KrashnKraka
"My money is on a timing issue, or wrong plugs."
Appreciate it!! :smile:
When I get some time to work on it this week we will find out. I could see the chuck key being an issue too as mentioned above. I do get a slight backfire when I shut it down. It's never had a valve job in 30 yeears for that matter.
Thanks again!
PS Just to be clear this issue started about 2 years ago. You are right though, since then it has been back in the shed at the end of the mowing season.:ashamed:
This is all good info in the thread... you should appreciate in a workshop environ it would
take some less time to find the problem than write up a post on what the problem may be.
For example when "timing issues" are written? That could prove to be anything from a
dislodged crankshaft key to a camshaft cog worn to the bejaysus. Better to keep it simple
and work on your feedback.
It aint a competition, with your posts being of the most value here, not the assorted
thoughts of those working from experience or logic, or both.
At the end of the day you will be mowing grass, cool.
That outcome should be the only priority.
Cheers...
#24
R
Rick'sToro8-32
R
Rick'sToro8-32
For all contributors and any who might be interested, because of increased mandatory overtime at work I still haven't had a chance to work on my mower and persue the detonation suggestion. But, I just looked this up before I am going to bed:
"Detonation, often called pinging, is nothing less than a series of small explosions that take place within an engine's combustion chambers. It can be extremely destructive, breaking pistons, rod bearings and anything else from the pistons down that a large hammer could damage. It is best avoided."
I thought I was hearing a rod knocking in my engine when I start to have trouble and start to konk out, but again this makes perfect sense and sounds right.
So, I will pull the head and clean any carbon and make this my first attempt at a fix, hopefully this week, and again report back. I'm only working in theory here like the rest of you even though the mower is in my shed, but in theory based on what I have explained above in this thread, my money is on detonation suggestion right now.
"Detonation, often called pinging, is nothing less than a series of small explosions that take place within an engine's combustion chambers. It can be extremely destructive, breaking pistons, rod bearings and anything else from the pistons down that a large hammer could damage. It is best avoided."
I thought I was hearing a rod knocking in my engine when I start to have trouble and start to konk out, but again this makes perfect sense and sounds right.
So, I will pull the head and clean any carbon and make this my first attempt at a fix, hopefully this week, and again report back. I'm only working in theory here like the rest of you even though the mower is in my shed, but in theory based on what I have explained above in this thread, my money is on detonation suggestion right now.
#25
KrashnKraka
"pinging"... low octane fuel in a high compression engine.
Ask any "hot-rodder" or "very fast bike" (in a straight line) rider about it.
Something to think on.......?
KK
KrashnKraka
[...]
"Detonation, often called pinging, is nothing less than a series of small explosions that take place within an engine's combustion chambers. It can be extremely destructive, breaking pistons, rod bearings and anything else from the pistons down that a large hammer could damage. It is best avoided."
I thought I was hearing a rod knocking in my engine when I start to have trouble and start to konk out, but again this makes perfect sense and sounds right.
"pinging"... low octane fuel in a high compression engine.
Ask any "hot-rodder" or "very fast bike" (in a straight line) rider about it.
Something to think on.......?
KK
#26
R
Rick'sToro8-32
I'm not sure what the point is here, it sounds like you saying detonation can only occurr in a high compression engine with low octane fuel?
In other words it sounds like you are saying it is not possible for a small engine to experience detonation.
R
Rick'sToro8-32
"pinging"... low octane fuel in a high compression engine.
Ask any "hot-rodder" or "very fast bike" (in a straight line) rider about it.
Something to think on.......?
KK
I'm not sure what the point is here, it sounds like you saying detonation can only occurr in a high compression engine with low octane fuel?
In other words it sounds like you are saying it is not possible for a small engine to experience detonation.
#27
KrashnKraka
Like not one single thing will cause pinging on it's own.
However I would go as far as saying low octane fuel in a small engine would not
cause "pinging"... the design simply does not develop the pressures required.
Maybe advanced timing in an engine with excessive coking might "detonate"
some fuel as the engine gets hotter. The heating being caused by the timing or
poor air circulation.
Anyway...enough theorising.
Let's wait until you have time fo spanner work, yeh?
KK
KrashnKraka
Nope...I am saying it takes a combination of circumstance.I'm not sure what the point is here, it sounds like you saying detonation can only occurr in a high compression engine with low octane fuel?
Like not one single thing will cause pinging on it's own.
That is a separate issue, see my response above.In other words it sounds like you are saying it is not possible for a small engine to experience detonation.
However I would go as far as saying low octane fuel in a small engine would not
cause "pinging"... the design simply does not develop the pressures required.
Maybe advanced timing in an engine with excessive coking might "detonate"
some fuel as the engine gets hotter. The heating being caused by the timing or
poor air circulation.
Anyway...enough theorising.
Let's wait until you have time fo spanner work, yeh?
KK
#29
H
Honda Tech
H
Honda Tech
Thanks very much for all of the posts! :smile:
If I am hearing things correctly it seems as though the consensus is that my mower is konking out after about 40 minutes of run time because of a timing issue.
It occurs to me that this mower has never had a valve job. It think poorly seated valves can mess up the timing. I wonder if this could be the 'cause' of the problem.
Also, in the back of my mind, I think I remember something about a vapor lock in the gas line that creates a situation like mine from a mower when I used to work at a local cemetery. It seems like we had a mower that would run until it heated up and then konk out and then run again when it cooled down. I think I remember the mechanic there saying it was a vapor lock or something like. Does anyone know anything about this?
That is the 'symptom' of my mower: simply put, it runs great until it heats up then it konks out--and when it cools down it runs great again until it heats up and konks out again.[I think you are on the right track. 30 year old engine that has never had a valve job? It not going to effect the actual timing, but will affect the cooling and power.] ]
#30
R
Rick'sToro8-32
Very good, thank you!!
I can appreciate that now looking back to a job I had a cemetery when I was younger. Each winter I would tear down small engines that quit running or had problems (mostly trimmer mowers), on these I would take the coke / carbon off the underside of the head with the wire wheel on the grinder (which was often pretty thick crust of carbon) and mill the heads, and do valve jobs as needed, and in the majority of the cases they went back out the next spring running strong like new.
R
Rick'sToro8-32
I think you are on the right track. 30 year old engine that has never had a valve job? It not going to effect the actual timing, but will affect the cooling and power.
Very good, thank you!!
I can appreciate that now looking back to a job I had a cemetery when I was younger. Each winter I would tear down small engines that quit running or had problems (mostly trimmer mowers), on these I would take the coke / carbon off the underside of the head with the wire wheel on the grinder (which was often pretty thick crust of carbon) and mill the heads, and do valve jobs as needed, and in the majority of the cases they went back out the next spring running strong like new.