Peter_C
Petty Officer 2nd Class
- Joined
- Jun 7, 2009
- Messages
- 193
I started running the battery of tests as I have the OEM manual, but so far everything tests good. I figured I would run it by some other people and see if they know what it "could be". The boat and motor are new to me but have minimal actual use.
The motor is a pull start 40 horse E40RETB of the 1993 vintage and of course 2 stroke, mounted on a 14' Zodiac. New plugs multiple times, since they foul when it misfires. New impeller since issue started.
When I first got it the motor ran great for hours. We were out on the Pacific ocean and I wrapped kelp around the lower unit and noticed the water flow diminish within 20 seconds of hitting a kelp patch. I stopped, cleared the lower unit and took off again. We took off at good clip then it started cutting out at a higher RPM. At a slower speed it runs fine. I have found if I let it cool down it runs like a champ for around 30-50 seconds then starts cutting out. If I rev the throttle a few times, again it will take off and run great then start acting up. If I just cruise at a speed a ways off idle which is about 1/5 throttle it will run great all day. Any more and it abruptly starts missing.
Their is a thermostat that I inspected at the top of the cylinder head, and it appeared OK. Should I just replace it?
How can I determine if my motor has the overheat circuit? The sensor readings never changed no matter how the boat was running. I tried grounding it and keeping it an open circuit and never saw or heard any kind of warning buzzer. The kelp plugging the intake may not have anything to do with the motors running conditions, instead could just be coincidence.
This is not a fuel related cut but ignition/electrical. It does not bog down, like a fuel issue would produce. Instead it is like 1/4 the firings are correct at higher RPM, and can be controlled by the throttle position. Hopefully that makes sense.
Any help would be appreciated.
The motor is a pull start 40 horse E40RETB of the 1993 vintage and of course 2 stroke, mounted on a 14' Zodiac. New plugs multiple times, since they foul when it misfires. New impeller since issue started.
When I first got it the motor ran great for hours. We were out on the Pacific ocean and I wrapped kelp around the lower unit and noticed the water flow diminish within 20 seconds of hitting a kelp patch. I stopped, cleared the lower unit and took off again. We took off at good clip then it started cutting out at a higher RPM. At a slower speed it runs fine. I have found if I let it cool down it runs like a champ for around 30-50 seconds then starts cutting out. If I rev the throttle a few times, again it will take off and run great then start acting up. If I just cruise at a speed a ways off idle which is about 1/5 throttle it will run great all day. Any more and it abruptly starts missing.
Their is a thermostat that I inspected at the top of the cylinder head, and it appeared OK. Should I just replace it?
How can I determine if my motor has the overheat circuit? The sensor readings never changed no matter how the boat was running. I tried grounding it and keeping it an open circuit and never saw or heard any kind of warning buzzer. The kelp plugging the intake may not have anything to do with the motors running conditions, instead could just be coincidence.
This is not a fuel related cut but ignition/electrical. It does not bog down, like a fuel issue would produce. Instead it is like 1/4 the firings are correct at higher RPM, and can be controlled by the throttle position. Hopefully that makes sense.
Any help would be appreciated.
