kbait
Commander
- Joined
- Nov 13, 2007
- Messages
- 2,471
Any clues? I'm reposting from a couple days ago:
'85 25hp johnson manual start motor runs perfectly, but when powering up in gear at about 2/3 throttle, it simply cuts out. I can keep it from shutting completely off if I reduce the throttle quickly, and then it 'catches' again. It seems to be ignition cutting out altogether on both cylinders at the same time. I recently installed a carb kit, as it had a sticky needle/seat. It would run wide open just fine before that issue. I also re-inspected the high speed jet, and it is not clogged at all. And pumping the fuel bulb has no effect, and fuel is fresh, vent is open. All hoses/lines/connectors appear fine.
I thought that perhaps some ignition wires (black and white) were shorting out as the stator was advanced past a certain point, so I pulled the recoil and plugs, put motor in forward at full throttle and spun the flywheel by hand and found spark from both plug wires. (I also replaced plugs)
When I installed the carb kit last week, I simply replaced the needle and seat, gaskets and packing. I did not remove 'boss plugs' or whatever they are and go any deeper into the carb. I don't think it's a fuel issue at all, since it seems to cut out just like you'd turn the key off (if it had one). Perhaps a bad pick-up coil under the flywheel that quits working at higher RPM? (would still spark by hand cranking). I don't think it's a kill switch, since I can still get spark on above test. I don't think it's coils - why fail and then work at the same time. Maybe ignition box? I haven't heard of one failing like that, and I don't want to throw $$ haphazardly. Thanks!
'85 25hp johnson manual start motor runs perfectly, but when powering up in gear at about 2/3 throttle, it simply cuts out. I can keep it from shutting completely off if I reduce the throttle quickly, and then it 'catches' again. It seems to be ignition cutting out altogether on both cylinders at the same time. I recently installed a carb kit, as it had a sticky needle/seat. It would run wide open just fine before that issue. I also re-inspected the high speed jet, and it is not clogged at all. And pumping the fuel bulb has no effect, and fuel is fresh, vent is open. All hoses/lines/connectors appear fine.
I thought that perhaps some ignition wires (black and white) were shorting out as the stator was advanced past a certain point, so I pulled the recoil and plugs, put motor in forward at full throttle and spun the flywheel by hand and found spark from both plug wires. (I also replaced plugs)
When I installed the carb kit last week, I simply replaced the needle and seat, gaskets and packing. I did not remove 'boss plugs' or whatever they are and go any deeper into the carb. I don't think it's a fuel issue at all, since it seems to cut out just like you'd turn the key off (if it had one). Perhaps a bad pick-up coil under the flywheel that quits working at higher RPM? (would still spark by hand cranking). I don't think it's a kill switch, since I can still get spark on above test. I don't think it's coils - why fail and then work at the same time. Maybe ignition box? I haven't heard of one failing like that, and I don't want to throw $$ haphazardly. Thanks!