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KT746 Locked up
#1
PTmowerMech
PTmowerMech
KT746-3011
BD: 08/02/2015
Feeling pretty good today, so I thought I'd check out why this Kohler was locked up.
It's impossible to turn from the engine fan. Put a big pair of channel locks on the crank (the rusty part, just below the crank seal) and gave it a tug in both directions, and it still wouldn't budge.
So removed the engine and the sump, and can't see any scaring on the bottom of the cylinders. No discoloration, as if it got hot.
I do know the owner told me he ran it without oil, so I'm guessing the damage is going to be on the top side of the cylinder.
I'm about to remove the heads.
It's kind of fun feeling good enough to pick up an engine and put it on the work bench. I'll probably regret it in the morning. LOL
BD: 08/02/2015
Feeling pretty good today, so I thought I'd check out why this Kohler was locked up.
It's impossible to turn from the engine fan. Put a big pair of channel locks on the crank (the rusty part, just below the crank seal) and gave it a tug in both directions, and it still wouldn't budge.
So removed the engine and the sump, and can't see any scaring on the bottom of the cylinders. No discoloration, as if it got hot.
I do know the owner told me he ran it without oil, so I'm guessing the damage is going to be on the top side of the cylinder.
I'm about to remove the heads.
It's kind of fun feeling good enough to pick up an engine and put it on the work bench. I'll probably regret it in the morning. LOL
#2
PTmowerMech
PTmowerMech
There's no broken rods.
I got one of the heads off, and it's got quite of bit of carbon build up, but the top of the cylinder looks ok. I had to get the 1" impact to get 2 of the head bolts out.
The other side, that's a different story. I have a bad feeling that 3 of the valve cover bolts are going to break off. The impact won't budge'm. So I put a 1/4 ratchet on it and it's bending the torques-bit teeth. I tried tightening, but they won't budge that way either.
I'm a little scared to try to heat them and let'm cool.
I darn sure don't want these valve cover bolts to break off.
I got one of the heads off, and it's got quite of bit of carbon build up, but the top of the cylinder looks ok. I had to get the 1" impact to get 2 of the head bolts out.
The other side, that's a different story. I have a bad feeling that 3 of the valve cover bolts are going to break off. The impact won't budge'm. So I put a 1/4 ratchet on it and it's bending the torques-bit teeth. I tried tightening, but they won't budge that way either.
I'm a little scared to try to heat them and let'm cool.
I darn sure don't want these valve cover bolts to break off.
#3
PTmowerMech
PTmowerMech
Better luck today. I got two more of the 3 remaining valve cover bolts out. The 3rd one wollered out the torx part. So, tomorrow my only option is going to be tacking a nut on top of this one.
I'm just glad the head hasn't broken off.
Still can't rotate the crank though.
I'm just glad the head hasn't broken off.
Still can't rotate the crank though.
#4
Scrubcadet10
Scrubcadet10
What size torx bit are they? i've gotten lucky a few times using the next size torx bit up, OR occasionally getting an Allen bit to bite...
#5
PTmowerMech
They're 30's. When it rounded out, The next size (allan head) was about all I could get in it. But that was too loose. I knew it was. but gave it a shot. And that didn't work either.
My map gas canister is empty. But I still have a soldering torch I might throw at it.
I might try filing off two sides to fit a wrench.
PTmowerMech
What size torx bit are they? i've gotten lucky a few times using the next size torx bit up, OR occasionally getting an Allen bit to bite...
They're 30's. When it rounded out, The next size (allan head) was about all I could get in it. But that was too loose. I knew it was. but gave it a shot. And that didn't work either.
My map gas canister is empty. But I still have a soldering torch I might throw at it.
I might try filing off two sides to fit a wrench.
#6
Scrubcadet10
Scrubcadet10
Pan heads, so no hope of getting vice grips on them?
#7
PTmowerMech
PTmowerMech
I kind of made a boo boo. A friend suggested that the crank bearings should come off, before removing the heads. He said the bearings would lock up before the rings. So I took one off. (The one side that I'd removed the head from) That piston was lose. But the crank still won't turn. So trying to get my socket on the other rod bearing bolts, and it dawned on me, rod bearings have a little side to side motion if they're not locked up. Sure enough, there's some wiggle to it. Which means the bearings aren't locked up.
My boo boo came from taking the first one loose, instead of just wiggling it.
Learn learn learn.
My boo boo came from taking the first one loose, instead of just wiggling it.
Learn learn learn.
#8
S
slomo
S
slomo
I usually just crack the bolts loose all around slightly then remove them all. Sometimes might retorque them all to get stubborn ones out. What ever works.....I had to get the 1" impact to get 2 of the head bolts out.
#9
StarTech
StarTech
First there is no KT746 according Kohler. It is a KT745.
Apparently no else has seen this before.
You have checked only three of the four bearings directly related to crankshaft. If it is what I suspect is wrong you're going to need to short block it if the owner of the Husqvarna mower is willing to do so. $$$$. Other wise another engine. $$$.
Now with that I going back to data harvesting the forum.
Apparently no else has seen this before.
You have checked only three of the four bearings directly related to crankshaft. If it is what I suspect is wrong you're going to need to short block it if the owner of the Husqvarna mower is willing to do so. $$$$. Other wise another engine. $$$.
Now with that I going back to data harvesting the forum.
#10
PTmowerMech
It's mine now. He traded it for some work last year. And I'm just getting to it. It's a winter project.
And no, I haven't checked out all the bearing yet. Just the two crank bearings. I'm getting there.
But before you go, here's something to help make you smile.
PTmowerMech
First there is no KT746 according Kohler. It is a KT745.
Apparently no else has seen this before.
You have checked only three of the four bearings directly related to crankshaft. If it is what I suspect is wrong you're going to need to short block it if the owner of the Husqvarna mower is willing to do so. $$$$. Other wise another engine. $$$.
Now with that I going back to data harvesting the forum.
It's mine now. He traded it for some work last year. And I'm just getting to it. It's a winter project.
And no, I haven't checked out all the bearing yet. Just the two crank bearings. I'm getting there.
But before you go, here's something to help make you smile.
#11
PTmowerMech
And correct you are, as usual.
Ha, when I finally got the crankshaft out, I was expecting roller bearings. So it looked like everything melted. But soon realized it was just the crankshaft machined to fit the hole.
I don't understand why there's no oil journal for the top bearing? Seems that would be a better place, so the oil could get the top and the bearing below. Or even better, two journals.
In fact, there should be roller bearings with oil journals. At least you wouldn't have to replace the whole block.
Thanks for the info, man. You really are a necessity around here. Even if you do get a little snappy sometimes. LOL ??
PTmowerMech
First there is no KT746 according Kohler. It is a KT745.
Apparently no else has seen this before.
You have checked only three of the four bearings directly related to crankshaft. If it is what I suspect is wrong you're going to need to short block it if the owner of the Husqvarna mower is willing to do so. $$$$. Other wise another engine. $$$.
Now with that I going back to data harvesting the forum.
And correct you are, as usual.
Ha, when I finally got the crankshaft out, I was expecting roller bearings. So it looked like everything melted. But soon realized it was just the crankshaft machined to fit the hole.
I don't understand why there's no oil journal for the top bearing? Seems that would be a better place, so the oil could get the top and the bearing below. Or even better, two journals.
In fact, there should be roller bearings with oil journals. At least you wouldn't have to replace the whole block.
Thanks for the info, man. You really are a necessity around here. Even if you do get a little snappy sometimes. LOL ??
#12
Scrubcadet10
Scrubcadet10
I thought your last day of posting was Oct. 25th of last year.First there is no KT746 according Kohler. It is a KT745.
Apparently no else has seen this before.
You have checked only three of the four bearings directly related to crankshaft. If it is what I suspect is wrong you're going to need to short block it if the owner of the Husqvarna mower is willing to do so. $$$$. Other wise another engine. $$$.
Now with that I going back to data harvesting the forum.
#13
B
bertsmobile1
If people will pay for quality then companies will make quality
The only engines I have seen rolling element bearings in are Honda & Generac and neither seem to be making engines for mowers any more .
B
bertsmobile1
IT is all about costsAnd correct you are, as usual.
Ha, when I finally got the crankshaft out, I was expecting roller bearings. So it looked like everything melted. But soon realized it was just the crankshaft machined to fit the hole.
I don't understand why there's no oil journal for the top bearing? Seems that would be a better place, so the oil could get the top and the bearing below. Or even better, two journals.
In fact, there should be roller bearings with oil journals. At least you wouldn't have to replace the whole block.
Thanks for the info, man. You really are a necessity around here. Even if you do get a little snappy sometimes. LOL ??
If people will pay for quality then companies will make quality
The only engines I have seen rolling element bearings in are Honda & Generac and neither seem to be making engines for mowers any more .
#14
Scrubcadet10
Scrubcadet10
FWIW, predators have dual ball bearings.IT is all about costs
If people will pay for quality then companies will make quality
The only engines I have seen rolling element bearings in are Honda & Generac and neither seem to be making engines for mowers any more .
#15
StarTech
StarTech
#16
Hammermechanicman
Hammermechanicman
I haven't seen a top roller bearing in a long time. Some of the old cast iron tecumseh engines had roller bearings at both ends.
#18
PTmowerMech
PTmowerMech
@StarTech @Rivets @bertsmobile1
What's the chances of honing this with some fine sand paper, and making it work? Now that the crank is out, I oiled it and slipped it back into place (with the help of a rubber mallet. I can turn it, just not by hand. The channel locks I'm using, to turn the crank over, I have to use a little force.
Obviously I wouldn't be able to sand it true to surface. But doing it carefully, and a little at a time, couldn't hurt too bad. After all, it's a winter project. And now a learning experience.
BTW, not having a oil journal on the top bearing just pisses me off. That's just stupid.
What's the chances of honing this with some fine sand paper, and making it work? Now that the crank is out, I oiled it and slipped it back into place (with the help of a rubber mallet. I can turn it, just not by hand. The channel locks I'm using, to turn the crank over, I have to use a little force.
Obviously I wouldn't be able to sand it true to surface. But doing it carefully, and a little at a time, couldn't hurt too bad. After all, it's a winter project. And now a learning experience.
BTW, not having a oil journal on the top bearing just pisses me off. That's just stupid.
#19
B
bertsmobile1
B
bertsmobile1
I have said this on more than one occasion, but just to drum t\it in.
Vertical shaft engines are just about exclusive to mowers and as such are made to be the cheapest engine it is possible to make that will actually run.
And when it comes to quality it is just a case of some being less cheap than others.
And this comes back from the "american Dream" that technology will deliver more at lower price every year.
So the engines just get cheaper every year till there is no profit in making them so one by one the companies that used to do it go bust or just exit the market .
The crank will clean up with a dip in cold HCl or hot NaOH followed up with a little polish with some Silvro ( 0-2 µ abrasive size )
The top bush area can be recovered by rubbing down the dags only so you do not touch the valleys, just the peaks and only just enough for the drank to spin freely in it
OR you can get it bushed , but the bush will need to be keyed into the crankcase
I use 85:5:5:5 leadded gunmetal ( you lot might call it leadded brass or leadded bronze ) which expands a poofteenth less than the aluminium so can spin when the case gets hot.
I only use a 0.0005" shrink fit as the first couple split the crankcase, although the original seizure could have started some cracks that I did not detect because I did not do proper crack testing .
Anyway about 1 in 5 top seizures will be recoverable with nothing more than a little polish on the shaft and the absolute lease work to the cases, those deep ruts will actually work as oil reservoirs to help prevent further seizures .
The big problem is in use the belts pull back on the crankshaft , the lower bush acts as a fulcrium point so if there is any excessive clearance in the top bush the crank will tilt and lock up.
So the engine you bench test will run just fine till you put it in the mower & engage the blades.
I have been caught out like this a couple of times
Vertical shaft engines are just about exclusive to mowers and as such are made to be the cheapest engine it is possible to make that will actually run.
And when it comes to quality it is just a case of some being less cheap than others.
And this comes back from the "american Dream" that technology will deliver more at lower price every year.
So the engines just get cheaper every year till there is no profit in making them so one by one the companies that used to do it go bust or just exit the market .
The crank will clean up with a dip in cold HCl or hot NaOH followed up with a little polish with some Silvro ( 0-2 µ abrasive size )
The top bush area can be recovered by rubbing down the dags only so you do not touch the valleys, just the peaks and only just enough for the drank to spin freely in it
OR you can get it bushed , but the bush will need to be keyed into the crankcase
I use 85:5:5:5 leadded gunmetal ( you lot might call it leadded brass or leadded bronze ) which expands a poofteenth less than the aluminium so can spin when the case gets hot.
I only use a 0.0005" shrink fit as the first couple split the crankcase, although the original seizure could have started some cracks that I did not detect because I did not do proper crack testing .
Anyway about 1 in 5 top seizures will be recoverable with nothing more than a little polish on the shaft and the absolute lease work to the cases, those deep ruts will actually work as oil reservoirs to help prevent further seizures .
The big problem is in use the belts pull back on the crankshaft , the lower bush acts as a fulcrium point so if there is any excessive clearance in the top bush the crank will tilt and lock up.
So the engine you bench test will run just fine till you put it in the mower & engage the blades.
I have been caught out like this a couple of times
#20
PTmowerMech
PTmowerMech
Thank Bert. The accent sound better in person. Trying to read it, I think I get it.
Much work, with 1 & 5 chance for a successful outcome. Not very good odds. Especially with all the work that needs to go into it putting everything back together, and hooking it all back up.
If I do anything. I doubt it'll be with the crank itself. As I see no way of any sanding evenly. So only the block.
I'm curious about one thing in particular. This is a solid steel crank rotating at a high RPM on an aluminum housing. Hardened aluminum, I suppose. That's amazes me.
BTW, the engines getting cheaper while the costs increase. That's not normally the American way.
Much work, with 1 & 5 chance for a successful outcome. Not very good odds. Especially with all the work that needs to go into it putting everything back together, and hooking it all back up.
If I do anything. I doubt it'll be with the crank itself. As I see no way of any sanding evenly. So only the block.
I'm curious about one thing in particular. This is a solid steel crank rotating at a high RPM on an aluminum housing. Hardened aluminum, I suppose. That's amazes me.
BTW, the engines getting cheaper while the costs increase. That's not normally the American way.
#21
PTmowerMech
Funny you should mention Predator. HF doesn't have a listing for a vertical shaft twin. I've search their sight like 3 times and all I get is a "Page not found" or a page full of horizontal engines.
PTmowerMech
FWIW, predators have dual ball bearings.
Funny you should mention Predator. HF doesn't have a listing for a vertical shaft twin. I've search their sight like 3 times and all I get is a "Page not found" or a page full of horizontal engines.
#22
B
bertsmobile1
The acid / alkali will eat off all of the built up aluminium on the steel which as mentioned will need just a tiny polish
The aluminium is a lot softer which is why it can be used as a bearing surface .
Oddly enough push mower engines are usually fine because the crank does not have belts dragging it to the back
So it is profitable ( sort of ) to fix a seized push mower engine but not worthwhile on a ride on engine that is 10 times the price.
Where I got caught out was I forgot to allow for the increased clearance when the cases got to full temperature
So the engine ran fine on the bench and fine when tested for a few minutes around the yard but failed when the customer started using them for an hour.
B
bertsmobile1
Do as little to the case as possibleThank Bert. The accent sound better in person. Trying to read it, I think I get it.
Much work, with 1 & 5 chance for a successful outcome. Not very good odds. Especially with all the work that needs to go into it putting everything back together, and hooking it all back up.
If I do anything. I doubt it'll be with the crank itself. As I see no way of any sanding evenly. So only the block.
I'm curious about one thing in particular. This is a solid steel crank rotating at a high RPM on an aluminum housing. Hardened aluminum, I suppose. That's amazes me.
BTW, the engines getting cheaper while the costs increase. That's not normally the American way.
The acid / alkali will eat off all of the built up aluminium on the steel which as mentioned will need just a tiny polish
The aluminium is a lot softer which is why it can be used as a bearing surface .
Oddly enough push mower engines are usually fine because the crank does not have belts dragging it to the back
So it is profitable ( sort of ) to fix a seized push mower engine but not worthwhile on a ride on engine that is 10 times the price.
Where I got caught out was I forgot to allow for the increased clearance when the cases got to full temperature
So the engine ran fine on the bench and fine when tested for a few minutes around the yard but failed when the customer started using them for an hour.
#23
PTmowerMech
Oh crap. So there's aluminum built up around the crank. I see it now. It's the dull finish, where as the steel is still shiny. Wouldn't muriatic acid remove that?
PTmowerMech
Do as little to the case as possible
The acid / alkali will eat off all of the built up aluminium on the steel which as mentioned will need just a tiny polish
The aluminium is a lot softer which is why it can be used as a bearing surface .
Oddly enough push mower engines are usually fine because the crank does not have belts dragging it to the back
So it is profitable ( sort of ) to fix a seized push mower engine but not worthwhile on a ride on engine that is 10 times the price.
Where I got caught out was I forgot to allow for the increased clearance when the cases got to full temperature
So the engine ran fine on the bench and fine when tested for a few minutes around the yard but failed when the customer started using them for an hour.
Oh crap. So there's aluminum built up around the crank. I see it now. It's the dull finish, where as the steel is still shiny. Wouldn't muriatic acid remove that?
#25
StarTech
I am just go stay on the OEM provided forums as they are a lot more professional and knowledgeable.
A note to PT; you need to see if you attend a technical training school over the winter to gain some basic knowledge of how these engines work overall as it seems that would be a time worth investment in your training for future repairs. I believe it will be of benefit to you to do so. You are willing to do the work, it just you lack some of the basics to build on. Good luck on your endeavors. I have spent 50+ yrs learning these repairs and still learn new things from time to time.
As of today I am fully retiring from this forum. No more mopping up.
StarTech
They did sell them last year but they are no longer available. They were actually rebadged Loncin LC2P77F engines with gross hp rating of 22 hp. More like 17/18 net hp engine.Funny you should mention Predator. HF doesn't have a listing for a vertical shaft twin. I've search their sight like 3 times and all I get is a "Page not found" or a page full of horizontal engines.
Actually I said Nov 1, 2021 so I am just mopping up some my threads that I was working on before Nov 1 but I had already stopped replying to new threads. All the mis-information on this forum is just an aggravation than I need right now. I have enough problems running my business right now. I have already removed the forum from my bookmarks and I am deleting the Firefox generated auto log password today to prevent myself from logging on anymore plus adding lawnmowerforum.com to my untrusted scripts in NoScript so FF will not even run the script without me manually overriding it.I thought your last day of posting was Oct. 25th of last year.
I am just go stay on the OEM provided forums as they are a lot more professional and knowledgeable.
A note to PT; you need to see if you attend a technical training school over the winter to gain some basic knowledge of how these engines work overall as it seems that would be a time worth investment in your training for future repairs. I believe it will be of benefit to you to do so. You are willing to do the work, it just you lack some of the basics to build on. Good luck on your endeavors. I have spent 50+ yrs learning these repairs and still learn new things from time to time.
As of today I am fully retiring from this forum. No more mopping up.
#26
PTmowerMech
You're going to miss us when you're gone.
PTmowerMech
They did sell them last year but they are no longer available. They were actually rebadged Loncin LC2P77F engines with gross hp rating of 22 hp. More like 17/18 net hp engine.
Actually I said Nov 1, 2021 so I am just mopping up some my threads that I was working on before Nov 1 but I had already stopped replying to new threads. All the mis-information on this forum is just an aggravation than I need right now. I have enough problems running my business right now. I have already removed the forum from my bookmarks and I am deleting the Firefox generated auto log password today to prevent myself from logging on anymore plus adding lawnmowerforum.com to my untrusted scripts in NoScript so FF will not even run the script without me manually overriding it.
I am just go stay on the OEM provided forums as they are a lot more professional and knowledgeable.
A note to PT; you need to see if you attend a technical training school over the winter to gain some basic knowledge of how these engines work overall as it seems that would be a time worth investment in your training for future repairs. I believe it will be of benefit to you to do so. You are willing to do the work, it just you lack some of the basics to build on. Good luck on your endeavors. I have spent 50+ yrs learning these repairs and still learn new things from time to time.
As of today I am fully retiring from this forum. No more mopping up.
You're going to miss us when you're gone.
#27
PTmowerMech
I think I got that done. And decided to just use the rider part for moving stuff from the front to back. Maybe check my mail. I'll definitely need it come spring. I asked my back and my knee about this, and they approved. LOL.
The crank looks good. It fit snug into the block. Had to tap it a little with a rubber mallet to get it all the way in. Now it's just putting things back together.
Turning the crank, I can do by hand. There was a little play in the side to side. But it wasn't loose play, if you know what I mean.
Well see when I get the oil seals. Looks like there's no seal on the sump.
Can these head gaskets be reused, like you can some Briggs?
PTmowerMech
Do as little to the case as possible
The acid / alkali will eat off all of the built up aluminium on the steel which as mentioned will need just a tiny polish
The aluminium is a lot softer which is why it can be used as a bearing surface .
Oddly enough push mower engines are usually fine because the crank does not have belts dragging it to the back
So it is profitable ( sort of ) to fix a seized push mower engine but not worthwhile on a ride on engine that is 10 times the price.
Where I got caught out was I forgot to allow for the increased clearance when the cases got to full temperature
So the engine ran fine on the bench and fine when tested for a few minutes around the yard but failed when the customer started using them for an hour.
I think I got that done. And decided to just use the rider part for moving stuff from the front to back. Maybe check my mail. I'll definitely need it come spring. I asked my back and my knee about this, and they approved. LOL.
The crank looks good. It fit snug into the block. Had to tap it a little with a rubber mallet to get it all the way in. Now it's just putting things back together.
Turning the crank, I can do by hand. There was a little play in the side to side. But it wasn't loose play, if you know what I mean.
Well see when I get the oil seals. Looks like there's no seal on the sump.
Can these head gaskets be reused, like you can some Briggs?
#28
Scrubcadet10
Scrubcadet10
are you sure of the model, Kohler plus isn't showing a KT746....?
#29
PTmowerMech
Yeah, I didn't have my glasses on. It's KT745.
PTmowerMech
are you sure of the model, Kohler plus isn't showing a KT746....?
Yeah, I didn't have my glasses on. It's KT745.
#30
Scrubcadet10
Scrubcadet10
PTO seal 25 032 06-S