airbus320
Cadet
- Joined
- Oct 14, 2015
- Messages
- 20
Johnson 1977 70 HP, 70EL77S - Bogs down when put in gear & throttle pushed forward.
After running my engine for a period of time, at full throttle...approx 10-15 minutes, I shut down. After approx 15 minutes or more, I restart, place it into gear and advance the throttle through approx 25% of the travel (sounds like it bogs down) then it quits. It starts right back up..NP. If I advance the warm up lever for about 30-60 seconds or just advance the throttle very very slowly and wait it out, it eventually recovers and starts to operate normally again.
Conversely, If I stop after running at full power for the same amount of time and re-start the engine shortly after, or within a few minutes, throttle advance is smooth, normal and the engine operates normally.
The problem only seems to occur after it sits for more than ten minutes in-between stops.
The saga continues...Any suggestions welcomed!
Thanks, JD
Note: The only above the waterline abnormality(?) noticed recently was quite a bit of exhaust coming from the two 1/2" holes just below the cowling. I havent noticed this before.
Just done:
Head gasket for intermittent missing/dead cylinder(s) #3 seemed to be the worst - Result is like night and day. No more missing or completely dead cylinder(s). Sounds and performs much better, except for aforementioned.
Carbs removed, completely disassembled, cleaned and rebuilt
New water pump installed
Plugs and (1) coil pack replaced
Done late last season:
Water jacket gasket, thermostat, power pack, (2) coils, plugs, prop and hub.
After running my engine for a period of time, at full throttle...approx 10-15 minutes, I shut down. After approx 15 minutes or more, I restart, place it into gear and advance the throttle through approx 25% of the travel (sounds like it bogs down) then it quits. It starts right back up..NP. If I advance the warm up lever for about 30-60 seconds or just advance the throttle very very slowly and wait it out, it eventually recovers and starts to operate normally again.
Conversely, If I stop after running at full power for the same amount of time and re-start the engine shortly after, or within a few minutes, throttle advance is smooth, normal and the engine operates normally.
The problem only seems to occur after it sits for more than ten minutes in-between stops.
The saga continues...Any suggestions welcomed!
Thanks, JD
Note: The only above the waterline abnormality(?) noticed recently was quite a bit of exhaust coming from the two 1/2" holes just below the cowling. I havent noticed this before.
Just done:
Head gasket for intermittent missing/dead cylinder(s) #3 seemed to be the worst - Result is like night and day. No more missing or completely dead cylinder(s). Sounds and performs much better, except for aforementioned.
Carbs removed, completely disassembled, cleaned and rebuilt
New water pump installed
Plugs and (1) coil pack replaced
Done late last season:
Water jacket gasket, thermostat, power pack, (2) coils, plugs, prop and hub.