Whats wrong with my mower? Help please!

[Coca Kohler]

I have a 10hp briggs with codes: Model 254707 Type 0140-01 Code 9303110
About 2/3 months ago I bought it as a complete wreck if a mower and I spent my spare time repairing it. It had a lot fuel in the oil so I replaced the it. I cleaned the carb out, reset plug gap and flywheel and coil gap. I found it needed a head gasket so I replaced that also.

But now the mower seems to have lost all compression except when it gets to one point in the engine cycle. It runs ok but I've noticed a bit of a power loss. Today I took the flywheel housing of earlier and noticed that the head gasket looks warped and I took the plug out but it seems ok to me but I'm not an expert yet haha I'm only 16. When I replaced the head gasket I checked the cylinder and valves and they were fine. It had one deep scratch in the cylinder but my dad (who's a truck mechanic) said that it looks like its been there a while. I torqued the head to the correct setting using a torque wrench and in the correct pattern. The breather hose goes into the air filter and it has a bit of oil at the bottom of the filter housing from the tube. I was thinking tht maybe the oil had gone through the carb and into the engine and maybe the oil caused the gasket to go bad???

Earlier i also retorqued the head and it was all exactly how I done it originally. But why would it lose compression and power? When I checked the cylinder i spun the engine over by hand and there were lines of oil left in the cylinder in some places but could that be bad piston rings???

Sorry about the essay but I hope it will help those of you who can help me. Ill add a few photos of what I found today and what I found a few months back when I changed the head gasket.

 

[KennyV]

The one deep scratch in the cylinder 'May' be from a broken ring... Do you have a lot of blow by? :smile:KennyV

 

[Coca Kohler]

Hi thanks for the response.
Do you mean smoke by blow by? The only smoke it's ever had was when I first got it running. Apparently it had been sitting for 5 years. I thought the rings may of been worn because of the lines of oil left it the cylinder when it was turned by hand. Another thing, it tends to struggle to hold an idle even when the carb is adjusted right it runs better but it just can't hold an idle.

 

[KennyV]

Blow by... You will be able to see it in the crankcase vent tube attached at the carb, if you have too much it likely will not idle & your compression will be lower. ... :smile:KennyV

 

[Coca Kohler]

Do you mean blowing through the breather hose? The breather hose does make a loud hissing sound when the engine is spun over. Is that a sign of worn ring? Thanks for the help.

 

[Coca Kohler]

I'm not sure if it does have blow by. But the oil always appears to be very clear even though in my other lawn tractors with same oil it has gone darker.

 

[Two-Stroke]

Hey -- great username -- that's coming from an Atlanta resident. :thumbsup: [home of Coca-Cola]

I don't have any experience with your engine but I can suggest that you look at the crankcase ventilation system. There shouldn't be oil spitting into the air filter. Have you asked your dad about that system? I'll bet he knows something about them.

If you can find a manual for the engine that might help.

 

[Coca Kohler]

Hi, thanks about the username. When I making my account I was drinking some coca cola so I thought of Coca Kohler. Haha

Later i will take the vent tube off and I will use the compressor to clean it out. Do you think i should take the valve cover off with the vent tube and check everything is ok behind there? I think my dad would know about the ventilation because before I done the grass cutting and work around our yard my dad use to do it. He has done some repairs in the past to small engines but because he works on nights he doesn't have too much time to look except for weekends.