# B&S 400707



## DukeNS (Aug 31, 2006)

I have a Troy Built riding mower with a B&S 14 hp twin engine. The mower starts fine and runs good, however after I shut it off it takes about an hour or so to get it started again. It's only like this after it's been ran, I thought maybe it was vapor locking so I removed the gas cap to no advail. Any ideas ? Thanks.


----------



## peppy (Jul 19, 2006)

In most cases, a buildup of grass and debris on the cooling fins and other areas prevents proper air circulation which is also common reason for exhaust valve failure  Hopefully you can correct it before it is too late


----------



## certifiedtech (Jun 30, 2006)

This is usually caused from loss of compression. Possibly a Blown head gasket, but what I have found more often then not is loss of valve clearance. The Exhaust valve always needs more clearance than the Intake valve for this reason:
While the engine is running the exhaust valve is red hot unlike the intake valve which is cooled by the air coming in through the carburetor.
With exhaust valve red hot it expands. If there is not a proper amount of
clearance between the valve stem and lifter when the exh, valve expands the lifter prevents the valve from completely closing on the compression stroke causing compression to blow out the exhaust port. Loss of compression also causes the engine to run hot. After the engine is shut off it will be hard to start or will not start until the engine has cooled down and the exh, valve is back to it`s normal size. ( in your case the clearance for Briggs 14, 16 & 18 hp Twin Cyl, eng, would be int,.06 exh, .010 with the piston on the compression stroke and both valves closed) A valve clearance test can only be made when the engine is "cold".


----------



## mdub (Feb 13, 2007)

I have this same motor in my Bolens ST140 Hydro. I started it up last week, and it was running fine. Then the motor started pulsing, and there was a POP, and it died. I can crank the motor fine, but it will not turn over. I am thinking a blown Head gasket, but have not dived into it yet. Does anyone have any thoughts?

Thanks,
Matt


----------



## mdub (Feb 13, 2007)

I pulled the motor shrowds off, and every square inch of cooling fin was stuffed with mouse nest debris. I will pull the cylinder heads off tonight when I get home. I really hope its the head gasket, and not a valve. My guess is that it would be cheaper to buy a new motor if thats the case, which would still be cheaper than a new tractor.


----------



## mdub (Feb 13, 2007)

welp, i think there is either a broken crank shaft or rod. The engine will no longer crank, and i was able to push one of the piston about 3 inches into the cylinder. Going to the dump i guess.


----------



## oscaryu1 (Mar 25, 2007)

Get your own thread please, Duke, look for sprak right after running, if your coil wrap is breaking, moisture gets inside tehre when runnig, so it cant start afetr wards.. when the moisture evaporates then you can start it. 

so in summarization to all the posts: 

check for compression after runing
check for blow gasket
check valves
clean the cooling fins on the block
check for spark after running


----------



## mdub (Feb 13, 2007)

well i am so sorry for taking this thread "Off Topic". Did you noticed that the last reply before me was from 2006? I was having an issue with the same motor, i did not think there was a need to start a new thread. My apologies.


----------

