kenimpzoom
Rear Admiral
- Joined
- Jul 13, 2002
- Messages
- 4,807
Does this sound like an ignition problem or carb problem?
93 Mercury Sport Jet 90 ( 3 cylinder inline, Force powerhead, three carbs)
Engine runs fine at idle, but low on power. I can ground the bottom cylinder spark plug and it makes no difference in the power, so it is definitely the bottom cylinder.
When running around at ? throttle, it will occasionally pick up speed and run correctly with full power, it only last a few seconds, then back to low power.
I have verified it has spark at idle on all three cylinders.
I am leaning towards an ignition problem (weak coil, shorted wire, powerpack failing, etc), but do you think it is possibly a carb problem? I would think if it were the carb, it would run badly all the time and never occasionally run right.
I am leaning towards swapping around the coils to see if the problem follows the coil, and also using the timing light to confirm spark while at speed.
Thanks, Ken
93 Mercury Sport Jet 90 ( 3 cylinder inline, Force powerhead, three carbs)
Engine runs fine at idle, but low on power. I can ground the bottom cylinder spark plug and it makes no difference in the power, so it is definitely the bottom cylinder.
When running around at ? throttle, it will occasionally pick up speed and run correctly with full power, it only last a few seconds, then back to low power.
I have verified it has spark at idle on all three cylinders.
I am leaning towards an ignition problem (weak coil, shorted wire, powerpack failing, etc), but do you think it is possibly a carb problem? I would think if it were the carb, it would run badly all the time and never occasionally run right.
I am leaning towards swapping around the coils to see if the problem follows the coil, and also using the timing light to confirm spark while at speed.
Thanks, Ken