"Leoma" low RPM's

[JD-MDR]

Went to Ventura today . The fires are really bad 115,000 acres. 430 structures. Luckily the smoke is not going over the harbor. they did, however, issue a warning to boil the water. I finished cleaning out the fuel tank and lines and the Racor filter canister. I got about 1 gal .of watery fuel from the bottom of the tank. Jabsco has a pump that goes on the drill motor. It worked really good and I used the vacuum cleaner to get most of the residue out. The tank has no access panel you have to go thru the inlet or where the gauge is. So I couldn't really clean it out perfectly. Somehow I don't think my low rpm problem is due to fuel flow. I bet its carbon in the mixing elbow. I'm gonna take the elbow off and run water through it to see if there is any restriction. I sure hope its not the manifold. I heard the new manifold coast $2000. Does anyone know if there is a way to clean out that carbon.

[jbenagh]

I had two similar problems with my MD7A:
1) the exhaust hose was crimped, restricting the flow. This caused an intermittent overheating and low power situation. I replaced the hose even though it looked great and problem solved.
2) the shutdown return spring was rusty so that the knob did not always go off. Some WD40 followed by a few drops of motor oil seem to have fixed that problem.

I did, in the course of diagnosing both of these problems, take the mixing elbow off and look into the manifold. I suspected exactly what you mentioned but it was perfectly clean. The above two things are much easier to check than removing the elbow (and #1 you do if you remove the elbow!).

Jeff

[JD-MDR]

The return spring on the stop lever?

[jbenagh]

The return spring on the stop lever?

Believe it or not, yes

[mgphl52]

The return spring on the stop lever?

Believe it or not, yes

I believe! Last summer I was out in the bay and my friend wanted to swim.
So we dropped sails and floated awhile. When I tried to start the MD7A, she refused.
After several attempts, I went below with a flash light and had my friend pull out the shut off and push it back in...
BINGO! The little, tiny, 35 year-old spring wasn't doing the job any longer. After manually resetting the shut off all was good.
I have since added another spring...

[JD-MDR]

I take back what I said about the smoke passing over the Ventura harbor. Yesterday and today was awful. Everybody is wearing respirator masks. The winds died down and all the smoke is sitting there. Both yesterday and today I drove the 50 mi back home after working on the boat. I'm still not getting rpm's above 1700 and it smokes. I took the mixing elbow off. It doesn't look bad to me but I think I need a new one. I can't get the nipples off one is spinning but not backing out I think the threads are gone but its still stuck in place.I'll let the shop take care of it so I don't damage the flange. Should I get bronze or brass nipple and 90 elbow instead whats there I think is just galvanized. I don't see any kinks in the exhaust hose . I will check the shut off lever. The cable is pretty stiff and hard to shut down. Maybe I'll get lucky again and that will be the problem. I don't understand why it all the sudden started running like this. I did loose up that knob on the single lever throttle shifter , that knob that disengages the shifter cable so you can throttle up without shifting. That knob was froze up. I didn't know it was there till someone showed me on his boat. any comments appreciated. Thanks

[JD-MDR]

I can't figure it out. I put the mixing elbow back on today . It wasn't bad. I soaked it in muriatic acid and the exhaust hose was clean. The stop lever OK. Iv'e cleaned all the fuel lines,filters and tank. Nothing has any effect on the rpm's and its smoking . From what I've gathered It is getting too much fuel. I don't know how to adjust the injection. The mechanic will come down after the new year. I guess they are busy. I don't understand how the injection can change all the sudden. I didn't tamper with anything. Also I had the diver clean the bottom and everything is perfect down there. I can still go out sailing if I want but the area is really smokey . The Ventura fire has burned about 250,000 acres and about 800 structures. Its really bad.

[Frenchy]

JD, One remote possibility- check for air intake restriction - clogged air filter, etc. Good luck - Jean