1958 35hp johnson misfire help please

sams58

Cadet
Joined
Jul 19, 2009
Messages
13
hello. i hope i am in the correct fourm. i have a 1958 johnson 35 hp motor. the problem i am having is when i start the motor it runs for about three seconds and then misfires so hard it sheers the key in the flywheel, its not a misfire like (BANG) (POW) OR (BACKFIRE) its more of a hard yank on the motor, almost like it tries to fire both cylinders at once, or turning the key off and on real fAST. i have not ran this motor in sometime but when i did it always yanked like this at idel just not as bad, if i remember correct it stoped when i got moving. any help would be appreacited. also does anyone know where i can buy more of these keys, i have been making them and ther a pain in the butt! THANKS AGAIN
 

coolguy147

Commander
Joined
Jul 14, 2008
Messages
2,817
Re: 1958 35hp johnson misfire help please

mmmmm? weird u sure it sheered ur flywheel key? probably due to not torqueing the flywheel down enough. usually they dont sheer unless this is not done.

ya i know what ur talking about cause i was playing around with my ten horse lol and press the kill button then release it comes back and really hard on 2 strokes. cause of the reeds may break so dont run tilll u fix it

check and see if ur flywhee key is sheered take flywheel off if not reinstall torqueing to 65-70 foot pounds. then make sure spark plug wires r installed to the right ones. coil clostest to carb is top cylinder. if all is good then clean carb and check spark is sparking not intermient probably should be checked before installing flywheel again
 

sams58

Cadet
Joined
Jul 19, 2009
Messages
13
Re: 1958 35hp johnson misfire help please

thanks coolguy, i have checked all of that and seems to be fine, flywheel has been torked and keys sheers still, its like the motor just slams to a stop..lol

mmmmm? weird u sure it sheered ur flywheel key? probably due to not torqueing the flywheel down enough. usually they dont sheer unless this is not done.

ya i know what ur talking about cause i was playing around with my ten horse lol and press the kill button then release it comes back and really hard on 2 strokes. cause of the reeds may break so dont run tilll u fix it

check and see if ur flywhee key is sheered take flywheel off if not reinstall torqueing to 65-70 foot pounds. then make sure spark plug wires r installed to the right ones. coil clostest to carb is top cylinder. if all is good then clean carb and check spark is sparking not intermient probably should be checked before installing flywheel again
 

coolguy147

Commander
Joined
Jul 14, 2008
Messages
2,817
Re: 1958 35hp johnson misfire help please

might have some other problem other then timing. take spark plugs out then put a screw driver into the hole. put poston top dead center to move a little and push screw driver and turn flywheel opposite direction if any play then something wrong in power head

hows compression

i dont know what to do in this situation never heard of such thing? something must be wrong:eek:
 
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