usedcarman
Cadet
- Joined
- Feb 13, 2010
- Messages
- 29
Hi Folks,
Bought this boat last fall, came with a 2002 Yamaha F100 4 stroke carburated engine, when i got it started this spring, it was misfiring on #4 and seemed to have very weak spark, seemed to be running on 2 or 3 cylinders, but specially bad on number 4. But it always starts up fine. Swapped plugs with #3 with no success, did a compression test which came up good 120psi to 150 psi. Pulled plug wire while running on #4 with almost no change, tried with #3 it then stalled. Next I swapped coils, top coil was running #1 and #4, bottom coil was running #2 and #3, unplugged them completely including unplugging the feed wire and swapped them, now #4 and #1 run good and #3 runs poorly as well as #2, am I right into thinking that I have a weak coil? How do I make sure that it is the coil that's the problem? How do I test it before purchasing another one, because once purchased electrical parts cannot be returned.
Any help would be greatly appreciated!
Bought this boat last fall, came with a 2002 Yamaha F100 4 stroke carburated engine, when i got it started this spring, it was misfiring on #4 and seemed to have very weak spark, seemed to be running on 2 or 3 cylinders, but specially bad on number 4. But it always starts up fine. Swapped plugs with #3 with no success, did a compression test which came up good 120psi to 150 psi. Pulled plug wire while running on #4 with almost no change, tried with #3 it then stalled. Next I swapped coils, top coil was running #1 and #4, bottom coil was running #2 and #3, unplugged them completely including unplugging the feed wire and swapped them, now #4 and #1 run good and #3 runs poorly as well as #2, am I right into thinking that I have a weak coil? How do I make sure that it is the coil that's the problem? How do I test it before purchasing another one, because once purchased electrical parts cannot be returned.
Any help would be greatly appreciated!