1998 Johnson Motor Trouble

[daystar554]

1998 50 Hp 2 cly Johnson, Starts good runs at idle speed good-advance speed slow up to about 1/3 speed, then motor shuts down to 1 cly missing bad but does not go dead, idle back to slow speed runs smooth.
One mechanic says "fuel pump".
One mechanic says "Stator". "WHATS WRONG?"

 

[petryshyn]

Re: 1998 Johnson Motor Trouble

Eliminate the fuel pump by squeezing the primer bulb when its missfiring. If it clears up when doing so, it may be fuel starvation (fuel pump, lines, fittings, vent, fuel filter)
It could also be ignition, so check for spark at each cylinder at the problem rpm (use a spark tester or plug grounded to block)

A restricted jet or port in the carb is also possible. Do the above tests first, then consider a carb cleaning if nothing else found....

 

[tashasdaddy]

Re: 1998 Johnson Motor Trouble

it is not the fuel pump, because both carbs would not be getting fuel. find out which cylinder is missing. swap the coils, if the problem follows the coil, you found the problem. if not then check the spark on the dead cylinder, if you have spark, then the carb is not putting fuel thru. if you do not have spark you probably have a bad power pack.