Stephen.M.Watson
Recruit
- Joined
- Jun 7, 2011
- Messages
- 1
1988 Excel
Starts and runs fine; planes out great, works fine under load until running above half throttle. At anywhere above 3100 RPM can get an intermittent dropped cylinder - doesn't fire and plug is wet on inspection. This is not an occasional misfire - it shuts down and remains shutdown. It is not isolated to 1 particular cylinder - it can happen to any cylinder.
Usual situation is start boat, warm up and then take off for a run, everything is fine and then after 5 to 10 minutes running at cruising speed, engine drops cylinder - noticeable drop in RPM, 500 or so at same throttle level. Drop back on throttle and problem will likely clear - kick it up again and problem will likely re-occur. Can often run for 30 minutes with no problem, can often run for 30 minutes with problem half of the time.
Running with water pressure gauge - pressure is good
Temp sensor tested fine
Suggestions?
Starts and runs fine; planes out great, works fine under load until running above half throttle. At anywhere above 3100 RPM can get an intermittent dropped cylinder - doesn't fire and plug is wet on inspection. This is not an occasional misfire - it shuts down and remains shutdown. It is not isolated to 1 particular cylinder - it can happen to any cylinder.
Usual situation is start boat, warm up and then take off for a run, everything is fine and then after 5 to 10 minutes running at cruising speed, engine drops cylinder - noticeable drop in RPM, 500 or so at same throttle level. Drop back on throttle and problem will likely clear - kick it up again and problem will likely re-occur. Can often run for 30 minutes with no problem, can often run for 30 minutes with problem half of the time.
Running with water pressure gauge - pressure is good
Temp sensor tested fine
Suggestions?