Briggs and stratton 5.5hp misfiring
- Thread starter Nathannewbie
- Start date
A flathead has a finned flat head (literally), no rocker cover (no rockers), usually has a vertical spark plug.
An OHV (overhead valve) will have a rocker cover (AKA: valve cover) usually made of stamped steel or cast aluminum, usually has an angled spark plug.
Check the B&S forum for photos.
https://en.wikipedia.org/wiki/Flathead_engine
https://en.wikipedia.org/wiki/Overhead_valve_engine
An OHV (overhead valve) will have a rocker cover (AKA: valve cover) usually made of stamped steel or cast aluminum, usually has an angled spark plug.
Check the B&S forum for photos.
https://en.wikipedia.org/wiki/Flathead_engine
https://en.wikipedia.org/wiki/Overhead_valve_engine
Added again,,,
Fuel with alcohol burns '''really hot'', & in just using that, can take out - ''burn''- an exhaust valve on a small engine, real quick.
Jay leno has vids on Ethanol fuel.
He is a pretty sharp Dude, & was a mechanic back in the day,, before his TV stuff ect.
His perspective of that, is pretty much mine as well.
Check them out.
Ian
Fuel with alcohol burns '''really hot'', & in just using that, can take out - ''burn''- an exhaust valve on a small engine, real quick.
Jay leno has vids on Ethanol fuel.
He is a pretty sharp Dude, & was a mechanic back in the day,, before his TV stuff ect.
His perspective of that, is pretty much mine as well.
Check them out.
Ian
Was the engine out of a snow blower or pump?
First thing I would do is check the valve lash on the exhaust valve.
If the valve is burned, the lash would more than likely be tighter, because of the valve probably into the seat more.
If that's the case, I would try adjusting that valve first, & set the gap a bit looser than spec. & then run it again & see if that helps.
If it does, you will have then probably pinpointed the problem.
eReplacementparts.com, has all the parts for that engine, & pretty decent instructions for fixing it.
Exhaust valve comes with a collar / retainer. & they have a complete top end gasket set for it including exhaust gaskets, for around 21 bucks.
I always highly recommend a new exhaust gasket, regardless.
I
First thing I would do is check the valve lash on the exhaust valve.
If the valve is burned, the lash would more than likely be tighter, because of the valve probably into the seat more.
If that's the case, I would try adjusting that valve first, & set the gap a bit looser than spec. & then run it again & see if that helps.
If it does, you will have then probably pinpointed the problem.
eReplacementparts.com, has all the parts for that engine, & pretty decent instructions for fixing it.
Exhaust valve comes with a collar / retainer. & they have a complete top end gasket set for it including exhaust gaskets, for around 21 bucks.
I always highly recommend a new exhaust gasket, regardless.
I
Was the engine out of a snow blower or pump?
First thing I would do is check the valve lash on the exhaust valve.
If the valve is burned, the lash would more than likely be tighter, because of the valve probably into the seat more.
If that's the case, I would try adjusting that valve first, & set the gap a bit looser than spec. & then run it again & see if that helps.
If it does, you will have then probably pinpointed the problem.
eReplacementparts.com, has all the parts for that engine, & pretty decent instructions for fixing it.
Exhaust valve comes with a collar / retainer. & they have a complete top end gasket set for it including exhaust gaskets, for around 21 bucks.
I always highly recommend a new exhaust gasket, regardless.
I
First thing I would do is check the valve lash on the exhaust valve.
If the valve is burned, the lash would more than likely be tighter, because of the valve probably into the seat more.
If that's the case, I would try adjusting that valve first, & set the gap a bit looser than spec. & then run it again & see if that helps.
If it does, you will have then probably pinpointed the problem.
eReplacementparts.com, has all the parts for that engine, & pretty decent instructions for fixing it.
Exhaust valve comes with a collar / retainer. & they have a complete top end gasket set for it including exhaust gaskets, for around 21 bucks.
I always highly recommend a new exhaust gasket, regardless.
I
It's out of a tiller.
Everything you need in terms of manuals (including lapping valves) is available at this link:
https://oldminibikes.com/forum/inde...e-manual-and-all-other-briggs-manuals.138045/
https://oldminibikes.com/forum/inde...e-manual-and-all-other-briggs-manuals.138045/
Take the valve cover off. Look for a broken spring. A weak spring "may" be compressed more than the other spring. Otherwise there is no visible way to tell.
From what you have posted....
New Carb
New Ignition
timing correct
New spark plug
That leaves the valves or perhaps the throttle linkage/governor is miss adjusted or hanging up.
Make sure the fuel line is not touching the linkage and the springs are in the right place/hole.
From what you have posted....
New Carb
New Ignition
timing correct
New spark plug
That leaves the valves or perhaps the throttle linkage/governor is miss adjusted or hanging up.
Make sure the fuel line is not touching the linkage and the springs are in the right place/hole.