Ok here is the background.
22ft pontoon was purchased last fall. I took a test drive with the current owner and the boat ran great aside from a very small bobble ( misfire ) around 2500 RPM. The engine started, idled, and once pushed past 2500 RPM would run WOT smooth without hesitation.
Fast forward to this spring.
Fuel tank was pulled from boat. Cleaned, inspected, and flushed with fresh gas. Filled the tank with non ethanol gas and a can of seafoam. Oil changed, Fuel filter replaced, Fuel pump cleaned and inspected, Fuel line and primer bulb replaced.
1st time out on water the boat ran great aside from the small misfire around 2500 RPM. Again If I was below this RPM or pushed past the boat ran great. Day two on the water was a different story. Nothing was changed from day one.
Day two after about 20 minutes of slow cruising the motor started to misfire and basically any RPM above Idle. Starts fine, Idles decent but give her any power at all above 1500 RPM and it bogs down. If I do not pull back the power it will stall but restart right away.
I have the factory service manual and these are the steps taken so far.
- Checked oil level
- Swapped plugs
- Checked im getting spark on all 4 cylinders at idle
- Resistance tested stator, both coils, auto enrichener, and spark plug caps - all come back in spec.
- Pulled and inspected plugs - Cylinder 3 looked wetter than the other two ( replaced )
- Tried a remote fuel tank - no change
Any thoughts? I am going to stop on the way home today and get a compression tester just to rule that out but do not think I have a bad cylinder since it was just tested in the fall and ran fine the first run in the water.
I am thinking either a clogged main jet or a bad coil.
Thank you for the help
22ft pontoon was purchased last fall. I took a test drive with the current owner and the boat ran great aside from a very small bobble ( misfire ) around 2500 RPM. The engine started, idled, and once pushed past 2500 RPM would run WOT smooth without hesitation.
Fast forward to this spring.
Fuel tank was pulled from boat. Cleaned, inspected, and flushed with fresh gas. Filled the tank with non ethanol gas and a can of seafoam. Oil changed, Fuel filter replaced, Fuel pump cleaned and inspected, Fuel line and primer bulb replaced.
1st time out on water the boat ran great aside from the small misfire around 2500 RPM. Again If I was below this RPM or pushed past the boat ran great. Day two on the water was a different story. Nothing was changed from day one.
Day two after about 20 minutes of slow cruising the motor started to misfire and basically any RPM above Idle. Starts fine, Idles decent but give her any power at all above 1500 RPM and it bogs down. If I do not pull back the power it will stall but restart right away.
I have the factory service manual and these are the steps taken so far.
- Checked oil level
- Swapped plugs
- Checked im getting spark on all 4 cylinders at idle
- Resistance tested stator, both coils, auto enrichener, and spark plug caps - all come back in spec.
- Pulled and inspected plugs - Cylinder 3 looked wetter than the other two ( replaced )
- Tried a remote fuel tank - no change
Any thoughts? I am going to stop on the way home today and get a compression tester just to rule that out but do not think I have a bad cylinder since it was just tested in the fall and ran fine the first run in the water.
I am thinking either a clogged main jet or a bad coil.
Thank you for the help
