4d61 fuel issues

[Coonneck]

Brought my new to me 27FC with the 4D61 engine home on Sunday from Louisiana to Mississippi a total of 36 NM. Half way through the journey the engine started to loose about 100 rpm’s for a few seconds then recover. This happened every few minutes for 3 hours at random intervals. So yesterday I changed both fuel filters and cranked it up and it idled up just fine for about a minute then started running rough and finely quit on me. I wallowed around the engine compartment few 2 hours checking and rechecking the lines, filters and priming the system. Once I got in running I took off across the bay to a ship yard to have it hauled and it started surging 200 to 400 RPM’s. I would slow it down and it would settle out then rev back up every few minutes. Anyone with any insight into this please pass along your knowledge.

[Bearkeley]

How were your filters? Sounds like you have gunk in your fuel. If you ran it in rough water, chances are, you unsettled the gunk at bottom of tank. It’s one of the most common issues with trawlers

[Coonneck]

The Raycor filter had a little debris but the secondary filter was very clean. The rough water theory is interesting but the entire ride did not include a wave over 1 foot other than a few wakes. In fact in was 6 hours of flat calm that started off at 80 degrees and ended at about 93 degrees with 90+% humidity. It was one hot ride I can tell you with certainty.

[nebulatech]

IIRC, your boat may have 2 fuel tanks. Are there inspection ports? How long was the boat sitting before you bought it? Without biocide, algea can grow in the tank. It may be clogging the fuel pickup tube in the tank. Just a thought

[Coonneck]

There are 3 inspection ports. The center one with the sending unit and one each on the forward corners with I assume a outlet and a return. Looks to me to be the original tank. Thinking seriously about replacement with twin 25 or so gal plastic tanks. Much easier maintenance and replacement if needed. Just don’t know how removing the old one will be.

[motthediesel]

I too would guess you have a fuel problem. To make certain, you could plumb in a temporary tank with fresh, clean fuel. A clean O.B. tank would do fine.
If you have the 70 gallon aluminum tank like ours, it can be slid out into the rear cabin. Not easy, but do-able.

[SalishAire]

Consider if there is any chance you are sucking air into the fuel lines someplace.

[Coonneck]

I just put in on the hard yesterday and plan a full service including all new hoses, rebuilding the injectors, manual temp, oil pressure and anything else I can find to take care of. Previous owner kept great records but passed away a few weeks after I purchased the boat so no one to check with as I go along.

[Agassiz- Albin]

https://www.albinowners.net/aog/viewtop ... 28&t=11784 check the fuel tank pick up tube, some tubes have a screen inserted inside that clogs up and stalls the engine, after the engine stalls, the fuel is vacuumed into the racor and the engine runs until the flow is restricted once again. The same thing happened to me.

[Coonneck]

Thanks Agassiz. I will check it out. Thinking of setting up a remote tank system to eliminate the tank, hoses, filters and fuel pump so I can pinpoint the problem. I’ll run straight out of the remote tank to the injection pump and run it to make sure it’s not in the pump. Then add parts of the existing system to see what part I add causes the problem.

[motthediesel]

That sounds like an excellent diagnostic plan -- let us know how you do...

[Agassiz- Albin]

Thanks Agassiz. I will check it out. Thinking of setting up a remote tank system to eliminate the tank, hoses, filters and fuel pump so I can pinpoint the problem. I’ll run straight out of the remote tank to the injection pump and run it to make sure it’s not in the pump. Then add parts of the existing system to see what part I add causes the problem.

No problem Coonneck, hope my experience can help any other Albin Owners. Btw, I also did what you are going to do, ran the engine from a remote tank and verified the lift pump, fuel lines, filters, hose clamps, blew out the fuel lines, (including the main tank pick up tube). I thought the pick up tube checked out ok, air would flow through. I put it all together after I drained the tank by pumping out all the fuel. The fuel I drained, had water and some sludge, so I put 4-5 gallons of methyl-hydrate in and then pumped that out. I thought I had a clean tank, which wasn't the case. On my next trip out,(25nm) I started to lose power, the screen was restricting fuel flow again. Thanks to a very observant fellow boater, who had started investigating this problem, I was asked if I actually pushed a wire through the pick up tube. No, was the answer and when i did try to push that wire through I found the screen, I couldn't believe it. So, that's what happened to me. Good luck on your challenge.

[ssrig]

Also checking the fuel vent screen is a good idea, met a fellow that had similar issues and it turned out to be the vent screen was caked shut.