eavega
Lieutenant
- Joined
- Apr 29, 2008
- Messages
- 1,377
Hi all.
I've been having a recurring problem with my 70EL76D. It will start and idle fine. If you try to roll on throttle, it will sputter and die. If you very slowly increase throttle, it will eventually let you get to full throttle. It won't rev to its full 5000-5500 RPM. Before the decarb, it would rev WOT at about 5300 RPM. After a WOT run, it has problems idling unless you raise the warmup lever a little bit. If you let it idle with the lever up a little bit, you can bring it back down and it will then idle normally. This started happening after I did a decarb and wired in an overboard switch earlier this spring. Here is what I have done so far and associated results:
Rebuilt fuel pump
Changed plugs
Replaced one old fuel line
Replaced spark plug boots (one was leaking spark)
Verified compression 110-110-105
Re-cleaned and rebuilt carbs including removal of core plug.
Verified good spark at the 30k air gap on spark tester
Verified timing with timing light at idle and at WOT.
Verified steady spark at all throttle range with timing light
Other maintenance I did this spring not associated with this problem; changed the LU oil, changed the impeller.
I am still convinced its a fuel issue, because it is only happening when fuel demand changes. The only other thing I can think of is that there were more serious problems with the fuel pump which the rebuild did not resolve. I'm going to replace the fuel pump with a new one, but after that I have reached the limit of my experience. I am looking to see if you all could suggest anything else that I can check.
Also, is there a safe way to run the motor WOT while it is stationary? I find it somewhat dangerous to be hanging over a spinning flywheel and prop while bouncing along on the water to do diagnostics.
As always, any comments or suggestions are most welcome.
Rgds
I've been having a recurring problem with my 70EL76D. It will start and idle fine. If you try to roll on throttle, it will sputter and die. If you very slowly increase throttle, it will eventually let you get to full throttle. It won't rev to its full 5000-5500 RPM. Before the decarb, it would rev WOT at about 5300 RPM. After a WOT run, it has problems idling unless you raise the warmup lever a little bit. If you let it idle with the lever up a little bit, you can bring it back down and it will then idle normally. This started happening after I did a decarb and wired in an overboard switch earlier this spring. Here is what I have done so far and associated results:
Rebuilt fuel pump
Changed plugs
Replaced one old fuel line
Replaced spark plug boots (one was leaking spark)
Verified compression 110-110-105
Re-cleaned and rebuilt carbs including removal of core plug.
Verified good spark at the 30k air gap on spark tester
Verified timing with timing light at idle and at WOT.
Verified steady spark at all throttle range with timing light
Other maintenance I did this spring not associated with this problem; changed the LU oil, changed the impeller.
I am still convinced its a fuel issue, because it is only happening when fuel demand changes. The only other thing I can think of is that there were more serious problems with the fuel pump which the rebuild did not resolve. I'm going to replace the fuel pump with a new one, but after that I have reached the limit of my experience. I am looking to see if you all could suggest anything else that I can check.
Also, is there a safe way to run the motor WOT while it is stationary? I find it somewhat dangerous to be hanging over a spinning flywheel and prop while bouncing along on the water to do diagnostics.
As always, any comments or suggestions are most welcome.
Rgds
. cannot recreate the motor failure on muffs. It will idle all day long on muffs or on the water for that matter. I need to be able to troubleshoot while the motor is trying to get to WOT.