John Deere LT155

[lefty]

I just wanted to confirm my opinion on this one.

John Deere LT155
MOL 155B046736

Unfortunately, I can't locate numbers on the engine. I think it's a Briggs but there are no numbers on the valve cover. Appears to be a 15HP OHV. I don't think most of you will need the engine numbers for this question but if you do, I'll try to chase them down. A friend brought it to me and it is in rough shape. Dirt caked in the cooling fins, mouse nest, the works. Some of the fins corroded down to thin metal, chewed through wiring and fuel line.

It doesn't run, obviously. I spin the flywheel and notice it's way to easy. So I find TDC and do a leak down. I put about 90lbs in without even bracing the flywheel and the other gauge reads like 9lbs. So thinking I'm not at TDC, while charging the cylinder with 90lbs, I turn the flywheel through all cycles. The flywheel spins easily with one hand with 90lbs going in.

I can hear the air switch from the carb, to the exhaust and to the sump with the dipstick off. My only thought is that I would have expected way more air and noise to be coming out of the dipstick during the compression stroke. So I was wondering, could this be as simple as a stuck exhaust valve? Or some other valve issue? I soaked the valve cover bolts with PB and am waiting to remove it. As it is, one of the valve cover bolts was already broken off and the others won't budge.

[bgsengine]

Bet you need to pull head off,and likely find a blown head gasket between cylinder and lifter galley. that or bent push rods and a valve guide shifted, holding valve open, perhaps.. if not both.. in any case, most likely need a head set,worst case, short block or re-power , best case you can get things freed up and un-stuck and just a head gasket plus other stuff to get 'er running

[KE4AVB]

If that is the original engine it is a Kohler Command CV15 if it is labeled as 15 HP.

With what you're indicating have you checked that the piston is moving up and down in the cylinder. Sounds to me like a broken rod.

[lefty]

Any tips for removing those valve cover bolts, not to mention head bolts, which I'm sure are just as frozen? I don't want to break them if it's just a head gasket issue.

Yes, the piston is moving up and down.

[KE4AVB]

I don't about the head bolts but the last couple times I pulled valve covers with seized bolts on a Kohler I had to break the screws (bolts). Then drill the 6 mm remains out and tap to 7mm - 100.

[lefty]

I got the valve cover off...only have 2 broken bolts. Pushrods look good. It appears like it has non-adjustable valves?

I guess my next step would be to pull the head? I'm not looking forward to that. The head looks like it's rotted. Heat damage?

Especially along the channel that one of the head bolts goes into. It's all pitted, cratered and deformed. I'm thinking that bolt is welded good in there. See photo. Am I just being paranoid? This thing is a mess.


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[KE4AVB]

Oh boy... Lefty personally I would just call it on this one if it is for a customer as this engine has severe unrepairable damage. If you are using this as a trainer project it is different as we all got learn on something. You ought seen some of the junk 2 cycle equipment I learned on. Most was barely worth recycling.

As for it not having adjusters that is because it has hydraulic lifters. And damage is corrosion and not heat related if my thinking is correct.

[lefty]

I thought as much. I might just pull the head then for exploration purposes and take a look at the gasket and cylinder. This machine has so many other issues that when all is said and done, it's probably not worth it. Thanks for the help.

[38racing]

I use a handheld impact that you hit with a hammer to start loosening the bolts

[Luffydog]

Can you look into the plug hole or screw driver In a feel the piston moving at all. I am with Ke4avb on this one looks like a none repairable unit or just a lot of or a learning