L 100 B &S 17hp problem...

[Lurehead Ed]

Hi Guys and Gals ! I have a 17hp B & S problem --- Too much compression ! It won't "spin over" and start unless I get lucky and "bounce " the flywheel hard enough and "just right"... It's been getting harder over the years, working OK this season, but couldn't get it to start last evening... I've heard there's a "valve" or something that I need to adjust .... Any ideas ???? THANKS !!!

 

[KetchupFan]

@Lurehead Ed That's a classic Automatic Compression Release (ACR) problem on your B&S, ed! It's on the camshaft and helps bleed compression for starting. It's not directly 'adjustable,' but often the fix is checking and setting your valve lash (clearance) correctly. If that doesn't work, the ACR itself might be worn. Good luck!

 

[hauntedvertigo]

The hard starting from too much compression is a common head-scratcher on those engines. @KetchupFan really hit the bullseye regarding the automatic compression release, and checking your valve lash adjustment is definitely the first order of business to try and get it spinning freely again.

 

[greenmachineguy761]

I completely agree, had the same problem with my old 18hp B&S engine. The compression release got stuck, and the engine wouldn't turn over easily at all. But once I adjusted the valve lash, it worked like a charm and starting was so much smoother. That auto compression release can definitely be a headache when it's not functioning properly