Briggs "Ready Start" High RPM

[wolfden793]

Hello! I have a Briggs "ready start" 6.5 HP engine that starts right up, but according to my tach, it's high end speed is over 5,000 RPM! Carb has been cleaned and governor shaft removed and passage in the sump body cleaned and reinstalled. Can't seen to lower to recommended RPM (about 3750 if I'm correct). Any help would be appreciated. All linkages are free and appear to work properly. Engine model is 125K02 0630 E1. Thank you!

 

[oldnslo]

Can you manually move the throttle shaft and get it to idle down?

what type of tach do you have? Reason for asking is that some engines fire every round so could read 5,000 when actually only 2,500

 

[wolfden793]

Hmm, not sure - I'll have to try. I have an electronic tach that if you put it near the spark plug, it reads RPM, before I cleaned the governor shaft it was running slightly slower (4500) but now over 5000. You can clearly hear the difference. Thanks for your input; I'll try the throttle shaft.

 

[KennyG]

I'm pretty sure most small engines are "wasted spark" engines, so unless your tach is adjustable for 2 stroke/4 stroke it will read 2x the actual rpm. If your engine has a simple flywheel sensor and coil ignition, it has to spark on both the compression and exhaust stroke.

I seriously doubt that a single cylinder B&S will run at over 5000 rpm. If you can get a vibration rpm sensor, you could check it with that.

 

[RandyT]

I'm pretty sure most small engines are "wasted spark" engines, so unless your tach is adjustable for 2 stroke/4 stroke it will read 2x the actual rpm. If your engine has a simple flywheel sensor and coil ignition, it has to spark on both the compression and exhaust stroke.

I seriously doubt that a single cylinder B&S will run at over 5000 rpm. If you can get a vibration rpm sensor, you could check it with that.

Briggs will run at over 5000 rpm just not for very long before the factory installed smoke escapes. I suspect the tach being used is for an every other revolution as opposed to fire every revolution like most small engine tachs are designed for.

 

[the old grind]

SGE rpm is set by governor adjustment vs carburetor. I use a photo-tach (HFT) vs an electronic that doesn't work without a spark to trigger the count.