12 hp briggs drowning in fuel

[backpack09]

Backstory:

12hp briggs i/c gold in a rear engine crapsman tractor

Tractor was running fine early this spring, then the ring gear stripped out. I parked the tactor and used a push mower the rest of the season.

Last week I finally get the time to swap in a new ring and starter gear.

I have compression (60 psi, but that sounds low) spark and tons of fuel (enough that it is spraying out of the muffler).

Now what happened? Did the valves go out of adjustment while it was sitting? or did my replacement of the ring gear, and quarter turn of the engine the wrong way make the timing chain slip?

I will be pulling the valve cover this weekend to look for something remarkable...

 

[maverick06]

how is the carb? I have only heard about that much fuel when the carb float floods.... I had an engine that took about 6 months for the carb to slowly flood...

 

[smokinj]

how is the carb? I have only heard about that much fuel when the carb float floods.... I had an engine that took about 6 months for the carb to slowly flood...

yep sounds like the floats are stuck open. Tap on the side of the carb somtimes that will free them up. Also try carb cleaner.

 

[heat seeker]

First - check your oil. If it's high, it may be contaminated with gas, and will smell like gas. Change the oil before running the engine, as it will not lubricate at all well.

Second - if you don't have one, install a shutoff valve in the fuel line, and use it.

Third - The compression is probably okay, many engines have an automatic compression release. Briggs says that if the engine "bounces back" when turned the wrong way, the compression is good enough.

Fourth - These engines usually use gears for the cam, so no chain to skip teeth.

Fifth - I agree that the carb float either stuck, or leaks. If you tap the carb, be gentle!

You might try removing the spark plug and turning the engine over a few times to clear the fuel out of the cylinder. Make sure the plug wire is well grounded, since a spark near flying gas and fumes could really liven up your day. If you have a new plug, put it in, if you must use the old one, make sure it's very dry.

 

[Jags]

First - check your oil. If it's high, it may be contaminated with gas, and will smell like gas. Change the oil before running the engine, as it will not lubricate at all well.

Second - if you don't have one, install a shutoff valve in the fuel line, and use it.

Third - The compression is probably okay, many engines have an automatic compression release. Briggs says that if the engine "bounces back" when turned the wrong way, the compression is good enough.

Fourth - These engines usually use gears for the cam, so no chain to skip teeth.

Fifth - I agree that the carb float either stuck, or leaks. If you tap the carb, be gentle!

You might try removing the spark plug and turning the engine over a few times to clear the fuel out of the cylinder. Make sure the plug wire is well grounded, since a spark near flying gas and fumes could really liven up your day. If you have a new plug, put it in, if you must use the old one, make sure it's very dry.

Do all of this + remove the spark plug for awhile and make sure that ALL the gas is out of the muffler (BOOM)

You got a stuck needle valve. It may require a quick disassembly, but that is not really a big job. CLEAN CARB VERY WELL.

 

[Dune]

First - check your oil. If it's high, it may be contaminated with gas, and will smell like gas. Change the oil before running the engine, as it will not lubricate at all well.

Second - if you don't have one, install a shutoff valve in the fuel line, and use it.

Third - The compression is probably okay, many engines have an automatic compression release. Briggs says that if the engine "bounces back" when turned the wrong way, the compression is good enough.

Fourth - These engines usually use gears for the cam, so no chain to skip teeth.

Fifth - I agree that the carb float either stuck, or leaks. If you tap the carb, be gentle!

You might try removing the spark plug and turning the engine over a few times to clear the fuel out of the cylinder. Make sure the plug wire is well grounded, since a spark near flying gas and fumes could really liven up your day. If you have a new plug, put it in, if you must use the old one, make sure it's very dry.

Do all of this + remove the spark plug for awhile and make sure that ALL the gas is out of the muffler (BOOM)

You got a stuck needle valve. It may require a quick disassembly, but that is not really a big job. CLEAN CARB VERY WELL.

Could also be a hole in the float.

 

[MasterMech]

While you have the carb bowl off you can pop the float out quick and give it a shake. If it sloshes then it's sunk and you need a new one. At this point I'd change the oil out regardless because it's most likely contaminated (smells like gas) and the cylinder walls have washed down from all the extra gas. Remove the spark plug and add a bit (1 tsp will do) of oil to the cylinder and crank it over. Reinstall the plug and once you have the carb straightened out and clean oil in it. Crank it with the throttle wide open (no choke!) until it starts or you're sure it's not going to (15 seconds max!). Then proceed like you would for a normal cold start. Warning, with that bit of oil in cylinder it will smoke pretty heavy for 30 sec or so.

 

[boatboy63]

This is also a good time of the year to add fuel stabilizer (Stabil). Mix it in with the fuel, run the engine for 10 minutes or so to help it get into the carb. It will actually put a coat of something like oil in the carb and prevent the fuel from varnishing and turning "sour". This all needs to be done at the end of the season when engine won't be started for awhile. You will thank yourself next spring when your seasonal gas engine fires up as normal.

 

[kettensäge]

First - check your oil. If it's high, it may be contaminated with gas, and will smell like gas. Change the oil before running the engine, as it will not lubricate at all well.

Second - if you don't have one, install a shutoff valve in the fuel line, and use it.

Third - The compression is probably okay, many engines have an automatic compression release. Briggs says that if the engine "bounces back" when turned the wrong way, the compression is good enough.

Fourth - These engines usually use gears for the cam, so no chain to skip teeth.

Fifth - I agree that the carb float either stuck, or leaks. If you tap the carb, be gentle!

You might try removing the spark plug and turning the engine over a few times to clear the fuel out of the cylinder. Make sure the plug wire is well grounded, since a spark near flying gas and fumes could really liven up your day. If you have a new plug, put it in, if you must use the old one, make sure it's very dry.

Do all of this + remove the spark plug for awhile and make sure that ALL the gas is out of the muffler (BOOM)

You got a stuck needle valve. It may require a quick disassembly, but that is not really a big job. CLEAN CARB VERY WELL.

Could also be a hole in the float.

Yep, or a piece of grass or dirt stuck in the needle and seat.