OutdoorKing Repair Forum Forums Repairs and Maintenance Questions on Engines Questions On Briggs & Stratton Engines 3.5 to primer start question

Have a Series 200 motor, tested Ok 90psi. running ok, no smoke, was a bit rough, put it down to the carb being one i hadnt cleaned out. Pulled the stuff off it, put the primer start gear on it, carb, flywheel etc and it wont start. Backfires through the carb. Was thinking it was rich due to no filter so i put one on, still doing it. Swapped another carb/tank onto it, still doing it. Swapped the coil out, still doing it.


Any ideas???


I was thinking of going back to the old carb (if i can remember which one)
or perhaps the muffler is clagged.


A bit annoyed with it, had to mess about to get a blade disc sorted for it, masport bolt pattern, no discs to suit.

Dont want to spend too much more time messing with it.

Bob.

carefullt compare the new flywheel to the old one as to magnet position and keyway position, if these are different just put your old one back on.

I agree with Joe, grossly wrong ignition timing would produce the symptoms you are getting. A thoroughly blocked muffler might do the same. If you just put the old flywheel back on and try it, you'll probably save some messing about. Remember, it has to be one of the components you replaced that caused the problem.

You didn't accidentally leave out the flywheel key did you Bob?

I compared the flywheel and it looked the same, that had occured to me.
I put the key in, i even took the cup off again to check that i had. lol.

So the gear start flywheel will work with the latermodel pull cup and curved vane etc???

Its one of the ones i might have to come back too. Got some more in to fix.

I will keep you all posted.

Turns out it was a dud spark plug.


It got sat aside for a while and then i got back to it.
Did the same thing again, put a plug in it and away it went.

A bad spark plug does not explain firing through the carburetor. There may be something else wrong.

It may have been spitting, rather than firing, through the carburetor. This is a sign of lean mixture, and might have happened if you had not primed it for a cold start.

Nah it happened when i primed it.

I got it out and tried it again, still did it. Put a new plug in it and away it went.