Troybilt Superbronco 46 inch deck with 20 HP Kohler Courage - massive oil leak

hello all,

I have a massive oil leak that came up out of nowhere over the last two mowings. After the first, I found that all the crankcase bolts around the front of the engine were lose. Not lose, like backed out a millimeter or two and finger lose. I tightened them down, but, the leak is still there.

Before I look into a new gasket, or tear downs, is this common and is there a common bolt that might be in there that I didn't see that came out or lose?

If that is a single cylinder Courage, you will gave a crack down the exhaust side of the crank case near where the cylinder meets it.

Kohler were doing warranty replacements but this problem is very old now and claims may have closed, you will need to check with Kohler.

I have done a dozen or so with mixed success.
The crack will grow till it gets to the bottom and leak a lot of oil and in the worse cases, cause a loss of impulse signal to the fuel pump.
You can drill 1/4 past the end of the crack to stop it then use your favourite putty.
You can torch weld it
You can mig weld it

I torch weld ( DHC 2000 ) them in situ , took a while to get it down pat.
Whatever you do , wash out the front bolt holes and the bolts then refit with some medium strength loktite

bertsmobile1 said:

If that is a single cylinder Courage, you will gave a crack down the exhaust side of the crank case near where the cylinder meets it.

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<sigh> that's sad news. I'll tear into it tomorrow morning to see how bad it might be

This makes a little sense since the thing just SUDDENLY started throwing up oil. gasket leaks don't get that bad that fast

Just FYI, I've confirmed that there is a nice crack starting from the top going down on the front to the left of the head (as viewed from the front of the engine).

I'll try to stop the crack and fill it with JB weld. I suspect that it won't hold too well because of the speed of how quickly this crack showed up. It was only in about 1 to 1 and a half hours of operation from no leak to spitting out oil.

IT will work to an extent depending upon how bad the original crack was.
Make sure you drill a hole about 1/4" about 1/4" past the visible end of the crack.
take the belts off and you can leave the engine in place.
Off with the flywheel , stator then top plate.
clean the crack really well, carb cleaner followed by acetone.
Roughen the area to give the JB a key the fill the crack & hole put the top plate back on and do it up tight.
leave it for a full day then remove the top plate clean off all the debris, smooth the JB clean & reassemble.
Clean out the bolt holes and then use a few drops of BLUE locktite on the front bolts.

Before you do anything, contact Kohler with your engine's serial number.
Some will get a replacement short block but it will have to be done through a dealer so will cost you some money.

JB seems to hold up pretty well.
It weeps a bit ( well all mine have ) but some I did 4 years ago are still running quite fine apart from the fact they weep up to a pint of oil from under the patch between services.
One is used by a sports club and mows about 3 acres of the outfield weekly during in season.

From here on in, make sure you check the oil regularly and check the bolts eash season when you remove the blower housing to clean the fins at the end of season.

bertsmobile1 said:

Before you do anything, contact Kohler with your engine's serial number.
Some will get a replacement short block but it will have to be done through a dealer so will cost you some money.

JB seems to hold up pretty well.
It weeps a bit ( well all mine have ) but some I did 4 years ago are still running quite fine apart from the fact they weep up to a pint of oil from under the patch between services.
One is used by a sports club and mows about 3 acres of the outfield weekly during in season.

From here on in, make sure you check the oil regularly and check the bolts eash season when you remove the blower housing to clean the fins at the end of season.

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thanks I'm not going to put too much more money into it. I got it used year, and the plan was to get something new this upcoming spring. I just need it to last for about another few months of this season and into next.

It is interesting to see that yours held so well. My repair seems fine, but I have a new problem

Thank you all for your help on this. I JB welded the crack, and did a test run, and it seems to hold pretty well. I also coated the inside of the block with Utra Black RTV. I don't know if that will help but it seems fine and holding strong. The engine has a soft tick now, so I wonder if something happened when the top bolts were lose. It shouldn't be the valves, since I did the valve adjustment while I had everything off.

I have a new related issue. The top gasket has blown out. The entire thing was torqued correctly, and a thin coat of ultra black on top and bottom of the gasket, and all bolts red-loctited. This happened bout an hour into my yard yesterday, and seemed to get progressively worse, so it didn't all spit out at once. I couldn't see it under the plastic cover, so I can't be sure how it progressed.

Now, I'm assuming that the block and top cover are now out of tolerance, and that now has a larger than normal opening between the top cover and that edge of the block facing the head. I did a quick look last night, and didn't see any cracks up there, but, I guess it wouldn't surprise me.



any thoughts on that one??

again, thanks all!

jbeazell said:

thanks I'm not going to put too much more money into it. I got it used year, and the plan was to get something new this upcoming spring. I just need it to last for about another few months of this season and into next.

It is interesting to see that yours held so well. My repair seems fine, but I have a new problem

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But I am a bog specialist from way back.
Some did need to be redone, that all weep but most people are happy just getting a few more seasons out of the mower , then another, then another.
A couple of litres of oil a season is a lot less than a new engine or mower.
Now I can weld them without warping the cases or making more holes than I can fill.
And of course having gotten the repair down pat none have come in since then.

well... nevermind. I just looked closer, and all the front bolts are lose, again. I mean to the point where I could just back them out with my fingers, again, just like last time. My JB weld also now has a big crack through it that follows the general path of the old crack, so that needs to be chiseled off and redone. I'm annoyed that this happened, since I used red locktite on those bolts. In fact, I almost needed to get an extractor for one of the rear bolts as it got stuck in there. I need to get a new bolt since I tore it up getting it out.

I think I'm going to take this thing out back and lite it on fire. Anybody care to donate to the troy bilt bon fire cause?

Blue locktit is what the factory fits and blue will do.
If you use red you need to heat the cases before you try to remove the bolts.
You may have worn the front threads to the point that they will not hold when hot so either helicoil the 4 front ones or go up to a larger size bolt.
IF you want to make it a NASCAR mower you can always drill the bolt heads and fit lockwire