MUFFLED BACKFIRE WHILE RUNNING - BRIGGS

[shillnav]

Got a Briggs 28B707, 1120-E1....... It starts and runs ok but has a muffled type backfire out of the muffler... Occasionally it will go away for a brief period, very brief.......... Does anyone have any idea what may be causing this??

Thanks Much

 

[motoman]

Don't know what the motor is from the PN , but mine burps, backfires , and misses when the valves are out of adjustment. Suggest you check it asap. You could lose a pushrod or worse.

 

[shillnav]

Thanks........... Will check the valves in the morning. It's not an OHV engine so if they're way off, I don't think I'm capable of doing anything except take it to one of the local shops...............

Thanks Again.

 

[shillnav]

Sorry, double checked and it 28R707, 1120-E1.......................

 

[shillnav]

Just noticed that the muffler, which is under a shroud is loose........ Could this be causing the noise?? Not going there tonight but am hoping that might be all it is...............

Thanks

 

[motoman]

shil, well recently it was stated that side valve set ups were quite stable, but did require a pull down and custom valve tip grinding or replacement if a lash problem came up. Sorry , don't remember the thread, but within the last week and responded to by a pro in CA.

 

[LakeRat1]

It could be that the Flywheel key is just a Little given/ almost sherred, that will put it just a little out of time and could cause this, Just Thinking, also a small Vacum leak can cause it to back fire, as a Kid we use to pull off a Vac. hose, when you would let off on the gas it would Really Back Fire, Wake up Tje Whole Town as we came through

Rat

 

[shillnav]

I removed the loose muffler and replaced the gasket............. Didn't solve the problem.

Removed the breather to check the valves. Tried it at Top Dead Center and also 1/4" below TDC and in neither position was I able to get a feeler gauge in between the valve stems and the tappets........ It is tight. Is this a pretty common accurance for an old engine?? It's got 10 years on it and no telling how many hours......... Also if the valves do need grinding, etc., I'm thinking that this could be causing the noise....... Is this correct??

Thanks for the replys and feedback..............