Valve Adjustment on a Briggs and Straton flat head engine

wsmm

Member
I have a Briggs and Stratton Model 252707 engine in my lawn tractor. I need to know how to adjust the intake and exhaust valve. Do you measure for clearance at top dead center on 1/4" down after top dead center. Is the procedure the same for both valves. Reason I'm I'm asking is my engine is hanging up when trying to start it with the electric starter. Battery is fully charged, it seems like the compression is stopping the engine from turning all of the way over. With the plug out it turns over fine, no compression. With the plug in it seems to hang on a regular basis. When it does hang when the stater disengages it seems to kick back counter clockwise. Have done a compression and leak down check. Compression is good, maybe even a litle high. Haven't checked it again recently, am about ready to put the lawn tractor out of its misery. Stopped running last year as I was putting it away. I have managed to start it twice it started this no start condition. If I remember correctly one or both times I had to use starting fluid.
 
Too much clearance on the intake valve will cause that problem, you need to find the correct clearance before you start, and most likely you'll need a new valve, they have to be ground off bottom end to set clearance, it's kinda touchy, and you end up with too much.
 
You can start with is it an OHV engine? Will have a little aluminum cover with OHV stamped in it. You need .oo4 and .oo6 feeler gauges. Couple of sockets and a torx bit. This video, the guy talks a little too much but he is doing it correctly. You will most likely have a valve setting up around 8 or even 10 thousand. Get back to us.
Adjusting a Briggs
 
Hope I didn't goof up. The symptoms you gave are very typically for the overhead valve engines. Well just get back to us.
 
Nope...plugged in the number you gave. I gave you the correct information. Looks like this?
cvphoto22797.jpg
 
(quoted from post at 10:49:09 05/11/19) I have a Briggs and Stratton Model 252707 engine in my lawn tractor. I need to know how to adjust the intake and exhaust valve. Do you measure for clearance at top dead center on 1/4" down after top dead center. Is the procedure the same for both valves. Reason I'm I'm asking is my engine is hanging up when trying to start it with the electric starter. Battery is fully charged, it seems like the compression is stopping the engine from turning all of the way over. With the plug out it turns over fine, no compression. With the plug in it seems to hang on a regular basis. When it does hang when the stater disengages it seems to kick back counter clockwise. Have done a compression and leak down check. Compression is good, maybe even a litle high. Haven't checked it again recently, am about ready to put the lawn tractor out of its misery. Stopped running last year as I was putting it away. I have managed to start it twice it started this no start condition. If I remember correctly one or both times I had to use starting fluid.

It is an 11hp flat head engine.
 
Definitely a flat head. Battery fully charged and check system on battery tester indicates battery is good.
 
I have two riding mowers with the same flathead 11 HP engine. Are you 100% sure the engine is not flooding? One of my mowers was doing the same as you describe. Ended up it was hydrostatic lock from too much gasoline. Was your plug wet when you removed it? Like some others said, it could also be your automatic compression release on the camshaft. I fixed mine by simply installing an in-line fuel shut-off valve that cost $2.
 

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