Engine Trouble

[Poppa Mikie]

We have an 1989 O'Day 302 which we purchased 3 years ago.

Recently, while motoring at 2200 rpm's, the Yanmar 2GMF engine started to lose power and drop down to 800 rpm's and then randomly go back up to 2200 rpm's. It did this numerous times in 30 minutes. Eventually, engine power was lost.

The following week, we changed both fuel filters because we thought that might be the problem. The fuel and the filters looked very clean. Then, we started the engine and ran it for an hour, with a load. Unfortunately, after about 15 minutes, it started doing the same thing.

Help! Does anyone have any new ideas?

 

[Ralph Johnstone]

99% Probability ....................

.................. says this is the culprit.

 

[Poppa Mikie]

.................. says this is the culprit.

Thanks Ralph Johnstone. This is our 1st boat so have alot to learn. We had both the exhaust elbow and the mixing elbow replaced in August 2012. Do you think it could be bad already or clogged up?

 

[31seahorse]

Your conditions regarding slow down of the engine resemble what we experienced on our Oday272LE with the 10Hp Westerbeke. The problem was dirty fuel. Build up in the tank which we could not see due to the tank location and fill tube shape. I removed the fuel pickup tube and found blockage of the tiny screen in that tube. Took the tube off the screw-in fitting; pushed the screen out with a metal rod; cleaned the screen with solvent; replaced the parts. I think that was the main problem. To insure clean fuel from then on I hired a man to "polish" the fuel. I was amazed to see the "crap" in the filters. Three sheets of filter material later the filter looked much better. In this whole process I also changed the onboard filters....water separator, fuel lift pump filter, and final filter. I changed the fuel lines also because a mechanic genius I know told me the inside of some fuel lines can break loose and cause temporary blockages now and then when old.
In retrospect, the metal screen would have probably made things right, but I do not regret the other changes.

 

[Poppa Mikie]

Your conditions regarding slow down of the engine resemble what we experienced on our Oday272LE with the 10Hp Westerbeke. The problem was dirty fuel. Build up in the tank which we could not see due to the tank location and fill tube shape. I removed the fuel pickup tube and found blockage of the tiny screen in that tube. Took the tube off the screw-in fitting; pushed the screen out with a metal rod; cleaned the screen with solvent; replaced the parts. I think that was the main problem. To insure clean fuel from then on I hired a man to "polish" the fuel. I was amazed to see the "crap" in the filters. Three sheets of filter material later the filter looked much better. In this whole process I also changed the onboard filters....water separator, fuel lift pump filter, and final filter. I changed the fuel lines also because a mechanic genius I know told me the inside of some fuel lines can break loose and cause temporary blockages now and then when old.
In retrospect, the metal screen would have probably made things right, but I do not regret the other changes.

Thank You 31seahorse

 

[31seahorse]

Poppa Mikie, You will probably need to do some fiberglass cutting to get at and remove the fuel pick up tube. If your fuel tank is a "briefcase" style located aft of the cockpit like our tank is let me know. We can discuss the removal process with private messages and I could probably provide some pictures if you like. Respectfully, Phil

 

[Ralph Johnstone]

Thanks Ralph Johnstone. This is our 1st boat so have alot to learn. We had both the exhaust elbow and the mixing elbow replaced in August 2012. Do you think it could be bad already or clogged up?

2012 is a little recent for the elbow to plug up but it's the easiest/cheapest thing to check after the new fuel filters you've installed.

 

[Poppa Mikie]

Thanks I will check on both things. If y'all think of anything else I would appreciate your thoughts, Mike

 

[Dream Weaver]

I recently had this problem. My alternator was failing. Replaced it and the problem went away.

 

[Poppa Mikie]

Thanks Dream Weaver, Do you know if there is a way to check the alternator to see if that is the problem before you replace it