Briggs engine runs well for an hour then starts smoking and looses power

lkjhG1948LMF

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  • / Briggs engine runs well for an hour then starts smoking and looses power
engine model=407777
engine type=0174 E1
Engine code=010511yh

This is a used tractor of unknown history that I have owned for a week. I removed all the fuel and replaced it with zero ethanol gasoline. We used it 3 days ago. It stalled out after about 1 hours use. Two days ago, I could not get it started. I removed the spark plugs and I determined that I flooded it. The sparkplugs were wet with fuel but were black with oil, too. The right cylinder had more oil on the sparkplug than the left cylinder. I had spark on both sparkplugs. I took a compression reading. Right cylinder 45 pounds. I assumed it has a compression release system. I was surprised that the left cylinder compression=160 pounds. I left the sparkplugs out of the engine. Today I installed the sparkplugs and the engine started. The engine ran well for about an hour. Then it happened again. It lost power, started missing, started smoking and stalled. I started it again and it sounded like a hit and miss engine. No matter the throttle setting engine did not stop missing and smoking. I drove it back to the barn, missing, smoking, with very little power. I had to restart several times.

What do you think about the compression differences? Would one cylinder have compression release and the other not? Do I have a fuel issue causing the smoking and perhaps need a carburetor cleaning? Would a valve malfunction present these symptoms? Are these engines worth tearing down for a piston ring replacement? Any other suggested solutions?
 

Scrubcadet10

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  • / Briggs engine runs well for an hour then starts smoking and looses power
Doesn't appear this engine uses a compression relief... this may be the cam that has the different grind on the lobes to act as the ACR. https://shop.briggsandstratton.com/...ings,_Connecting_Rod/4077770174E1/29870002B/y
45 PSI is even low for a compression relief system,, usually north of 60 on a good cylinder with a ACR.
Do a wet and dry compression test.... test compression on one cylinder, take note, put a little bit of oil in the cylinder through the plug hole, and if the reading is higher on the wet test, bad rings/cylinder.
 

bertsmobile1

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  • / Briggs engine runs well for an hour then starts smoking and looses power
Dip the oil , chances are it will be high .
Get some new plugs ( 4 at least ) for latter on once you have found the problems.
With new plugs once they are fouled they can only be burned clean
 

lkjhG1948LMF

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  • / Briggs engine runs well for an hour then starts smoking and looses power
Doesn't appear this engine uses a compression relief... this may be the cam that has the different grind on the lobes to act as the ACR. https://shop.briggsandstratton.com/pages/parts-lookup#/Briggs_&_Stratton/407777-0174-E1/Cylinder,_Crankshaft,_Camshaft,_Air_Guides,_Piston,_Rings,_Connecting_Rod/4077770174E1/29870002B/y
45 PSI is even low for a compression relief system,, usually north of 60 on a good cylinder with a ACR.
Do a wet and dry compression test.... test compression on one cylinder, take note, put a little bit of oil in the cylinder through the plug hole, and if the reading is higher on the wet test, bad rings/cylinder.
Doesn't appear this engine uses a compression relief... this may be the cam that has the different grind on the lobes to act as the ACR. https://shop.briggsandstratton.com/pages/parts-lookup#/Briggs_&_Stratton/407777-0174-E1/Cylinder,_Crankshaft,_Camshaft,_Air_Guides,_Piston,_Rings,_Connecting_Rod/4077770174E1/29870002B/y
45 PSI is even low for a compression relief system,, usually north of 60 on a good cylinder with a ACR.
Do a wet and dry compression test.... test compression on one cylinder, take note, put a little bit of oil in the cylinder through the plug hole, and if the reading is higher on the wet test, bad rings/cylinder.
left cylinder compression, cold=160 psi. Add oil; reads200psi
right cylinder compression, cold=45 psi. Add oil; reads 60 psi
 
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