Uh Oh... John Deere 125 (Briggs 20hp V-Twin)

[timmyd]

OK,

Good news, spark on non-firing cylinder.

Bad News:
1. plug keeps getting fouled with oil and gas
2. I bought a compression tester. 0psi on "bad" cylinder and 100psi on running cylinder, this was a dry test only. No point in a wet test if I have zero pounds?

So, I'm searching for an answer so I don't have to pull the head off the engine. I'm not a mechanic!

It looks like a stuck valve (maybe that was that grinding noise, the valve is broken?) or head gasket.

Anyway, should I attempt to use the tractor to do my chores, or is this a big no no (I bet it can't be good)

If I have to pull the engine (I can), it's going to cost me at least $300 at a machine shop to diagnose and fix... for twice the money, I can just order a new engine and replace it myself. Leaving me with a spare to tinker with and learn...

I'm hoping there is some solution in the middle! so, if you guys have any thoughts, I'd appreciate them!

Thanks a bunch.

Tim

 

[Carscw]

When you swap the plugs from one side to the other is it the same side that does not fire.
My 20hp was only running on one side yesterday was just a bad plug

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[timmyd]

When you swap the plugs from one side to the other is it the same side that does not fire.
My 20hp was only running on one side yesterday was just a bad plug

Sent from my iPhone using LMF

Yeah, same side every time, tried that... it didn't work

I'm doing my fall cleanup anyway, worse that can happen, I spend $600 on a new motor. It's really lost some power obviously, but getting the job done so far.

Once done, I don't use the tractor in winter, I have a separate snow machine, so I'll have nearly 5 months to look at the engine.

 

[Carscw]

I say run it hard till it blows then get a new one

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[KennyV]

Once you find No compression on a cylinder there is no reason to look further... You have found the problem.
The reason there is no compression is located In that cylinder.
Valves Not moving, (rocker stuck/broken or bent push rod or cam problem) piston rings broke or hole in piston. Head gasket problem....
You will have to look into that cylinder.
With that piston in a compression stroke, You could put compressed air into the spark plug hole, then check at the carburetor, muffler and the oil fill... it will give you a place to start looking. :smile:KennyV