No engine power

[zeilfanaat]

After a couple of weeks of inactivity, my engine (Universal M25 Diesel, with a little over 1,000 hours on it), is giving me a bit of trouble. It doesn’t seem to generate any power, and I can’t get it to run more than 1,800 RPM, even under full throttle. In fairly flat water with only a bit of breeze on the beam, she barely topped 2 knots!

I also noticed that, when in gear, the exhaust contains sooty, oily water. With the transmission in idle, the exhaust water is fairly clean, though. There isn''t any excessive smoke either.

Any ideas what the problem can be? Thanks for your help!

[paulk]

First thing I think of is clogged injectors. If you''re not getting enough fuel into the cylinders, you''re not going to get any power and you''re not going to be boosting rpm either. At idle, less excess fuel is showing up in the exhaust because there''s less fuel being pushed -- you''re in idle. Under load, with more fuel being sent in but not getting through properly, it''s showing up in the exhaust.
My $0.015 ( I don''t know enough to call it two cents.)

[Sludgemaster]

Yes, look at the fuel system. I suspect that you have air or an air leak in the fuel line or the return lines. This often happens when you leave the boat for a period of time. Check the filters and the lines for leaks and bleed the system. Check and make sure that your fuel is clean -- dip a stick in the tank and see if there is any microbial growth at the bottom of the tank. This looks like slime. If there is microbial growth, then it has probably clogged your secondary filter.

[Yodagwb]

Agreed. I would change the filters first and see if that corrects the problem. If it does then go after the fuel and find out what is causing the clog. If not, then move on to the injectors. If you pull them and take them to be tested make sure you keep the holes in the motor clean and protected.

[elhanley]

Could be watery fuel, possibly due to condensation in the tank. Test by running the fuel pump intake line to a container of clean, fresh fuel, and the discharge line directly to the injector pump, bypassing the secondary filter. If that cures it, discard everything in the regular tank, keep it topped off, use a dispersal agent and a biocide, and check for water in the tank with Water Probe Indicator.

[GarrettK]

You may also check to see if there is something wrapped on your prop. I was on a boat that had that problem - a random line was braided in the prop, but it would still spin.

No speed, no rpm and lots of black junk in the exhaust.