Topic: 12hp flat running poorly

[ntsure211]

Hey im new to racing and building my first mower and i skimmed the search and all that after reading several other posts any way i got a 281707 model 12hp flat i rebuilt it using a new rod for insurance bought it from prime small engines and checked everthing to tolerance as i viewed in other posts anyway installed back on mower runs like crap blows fuel from carb wont rev well i did make sure the cam and crank marks were aligned is the carb messed up or whats going on....

[George Herrin]

Sounds like flywheel timing is off or valve not seating.

[ntsure211]

if the flywheel key is intact and the wheel tight can you check the live timing with a light and can these motors be set  up to have advance built in

[George Herrin]

If the key is intact and flywheel tight I would find the bad running problem before I worried about advancing the timing.

[ntsure211]

ok i double check everything and now seems to run but really wont pull revs i do know that the carb may be wrong it came off an 8 rear engine but matched the pn# off the same on the 14.5 ohv what carb number do i need to be using

[benfield_boy]

I might be rong but it might be off timeing. Or it may be you have the gas/air mix to strong on the gas.

[Hotrodboy91]

you said it "blows fuel from the carb"
if you mean it leaks out from the end farthest from the engine,
it most likely means your got it adjusted wayyyyyyy too rich
float is not adjusted to sit level when fully seated,
or its likely that the float has a leak in it and is sinking
to the bottom of the bowl.

[ntsure211]

ok got it running it was a cracked key looked straight caused by improper torque on flywheel

[George Herrin]

Sounds like flywheel timing is off or valve not seating.

Thank you for posting what you found and the end result.