Universal diesel loses power

[Woody49]

Hi, I have a Catalina 30 powered by a 3 cylinder Universal M-25 that runs fine at the dock (even after 45 minutes) but stops after 10 minutes when underway even when the boat is not really heeling. The diesel tank shows no evidence of water or dirt. I’m out of ideas. Help, please!

[FPNC]

Air is entering the fuel system or you have a fuel restriction.

[Woody49]

Thx! I originally thought that there was enough fuel in the tank to keep the fuel intake tube submerged in fuel but I might be wrong because there are only a few gallons in the tank. Perhaps the fuel is low enough that even a little boat motion caused the intake tube to suck air instead of fuel. It certainly sounded like it was starved for fuel. I’ll add some fuel an make sure there are no fuel line restrictions and cross my fingers.��

[Engine man]

Hello - one method of troubleshooting is to take a clean container of fresh fuel, remove the hose from the boat's fuel tank, and insert it into the fresh fuel container. Now bleed the fuel system, get underway, and see if that solves the problem.

Some Catalinas had a screen on the end of the fuel pickup tube, [ inside the fuel tank] which had a tendency to accumulate crud. If possible, remove the tube from the fuel tank for inspection, and remove the screen, if found. Also closely inspect the tube for cracks, as metal fuel pickup tubes can fatigue, usually close to the top of the tank. The fuel system works fine at the dock, but getting underway opens the crack, allowing air into the engine's fuel system, and stopping the engine. Joe

Originally Posted by Woody49

Hi, I have a Catalina 30 powered by a 3 cylinder Universal M-25 that runs fine at the dock (even after 45 minutes) but stops after 10 minutes when underway even when the boat is not really heeling. The diesel tank shows no evidence of water or dirt. I’m out of ideas. Help, please!

[Woody49]

Thx Engine Man! I like your approach and I’ll try that. Much appreciated!

[skkeith]

I had this exact problem with a low profile tank. Turned out to be an improper fuel pickup tube (too short) complete with a rotten metal screen on the end further compounding the shortness. The way I found it was to put some clear tube inline, long enough so I could see it while underway. Once I saw the bubbles I knew for sure.