Problems with bad fuel

[foufou]

No one has mentioned the filter on the engine itself. On my Yanmar 3HM35 the filter on the engine is finer than the Racor so could also be clogged. Good luck

[Scout 30]

Originally Posted by Paul L

Make sure your tank vent is clear. You can open the fuel cap and run engine to see if that is the issue.

This is a good point. Insects like mud daubers can plug up your vent line which makes it hard to suck fuel out of the tank. The fuller your tank is the quicker this will take effect.

If you haven't already I'd install an electric fuel pump on a switch. I prefer having it first in line so that it picks up the fuel quickly & also pressurizes the line making it easy to spot leaks. This not only makes it east to prime the system but will help pump any stuff in the lines through to the filter & keep the motor running. Fuel flows through them so you only need it on when you need it.

[grantmc]

I recently experienced a similar problem (and perhaps someone has already proposed this issue). When I changed the filter and bled the system I must have tightened the filter up just a tad too much. There was a tiny crack in the plastic bowl at the foot of the filter that was letting in just a minuscule amount of air. So the motor would run fine for a while and then start running rough, no power, revs would drop, with occasional surges. I recognised the issue was the result of a classic air leak, but where? I confess I just couldn't figure and had to get a professional in and he spotted it in 10 minutes.

[oldjags]

Originally Posted by sailormed

Changing the Racor filter is not enough.
I had similar problems and the obstruction was IN the Racor housing. Fuel enters horizontal and then takes a bend to go down to the outside of the filter. There was gunk in this 90° bend!
So lines are clean, filters are clean, pickup tube clean but NOT the lines in the Racor itself!
Lesson learned.
To be honest I did not find this myself, but an old diesel mechanic on the island of Ponza on a Sunday evening. The bill was stiff.

Thanks! That's what it turned out to be. I had not completely disassembled the Racor and cleaned everything 100% the first time. The 90° bend all the way down to the little metal ball was filled with crap.

Will take her out for an hour or so later this afternoon just to make sure, but that's what was causing the vacuum inside the filter.

Thanks to all for the help!

[skipgundlach]

I'm glad you isolated your issue. I know how good that feels!

A potential consideration for your future motoring pleasure...

We had installed a fuel polisher in our initial refit (immediately before
our wreck); the tank was about half empty and had experienced in the
range
(based on the storm duration and the period of waves) 3-5000 impacts.
Ran the polisher in the first yard, changed the filter, ran it again on
the rock-and-roll trip back to the original yard, changed the filter, and
have yet, 3000 hours later, to change a Racor.

If you'd like to see our fuel polisher, all parts from McMaster-Carr,
click here (with apologies for lots of other pix intermixed:
Pictures: Flying Pig Early Refit + Projects/Flying_Pig_Has_Flown-Splash_and_More_Work/Getting_Close-Nov06

Morgan 461 #2
SV Flying Pig KI4MPC
See our galleries at Web-Folio -- Your Portfolio on the Web !
Follow us at http://groups.yahoo.com/group/TheFlyingPigLog
and/or http://groups.google.com/group/flyingpiglog

I expect to pass this way but once; any good therefore that I can do,
or any
kindness that I can show to any fellow creature, let me do it now.
Let me not defer or neglect it, for I shall not pass this way again.

- Etienne Griellet

[belizesailor]

Congratulations! Be sure you post how the test goes.

[oldjags]

All is back to normal! We went out for an hour and a half cruise and nary a hiccup. I ran it at full throttle for about 5 minutes just to make sure, and she ran like a top!

We brought a bottle of wine with us and celebrated the sunset!

[skipgundlach]

Originally Posted by oldjags

All is back to normal! We went out for an hour and a half cruise and nary a hiccup. I ran it at full throttle for about 5 minutes just to make sure, and she ran like a top!

We brought a bottle of wine with us and celebrated the sunset!

I expect you already know this, but Nigel Calder suggests you run your diesel at least an hour a month as though it was a performance planing hull - that is, WOT.

Diesels prefer loads, and if they don't get them, unhappy things happen with the piston rings.

A buddy boat complained about his black smoke typical, and doing the power boat routine cleared it right up

[DMBOS]

If you have a spin on Racor filter, there is probably a little ball that gets clogged on the top of the filter housing with a plastic cover you remove with a slotted screwdriver - ?????

[Sea Angel1]

Water and other chemicals may clog the fuel lines again and again.
A jelly substance is generated all over the reservoir.Therefore it happens, disappears and happens again and again. There is one solution: sorry to say but you should pump out the whole diesel reservoir, clean the reservoir thoroughly, fill with clean gasoline and filter it again. Refill and purge and start. Keep your fingers crossed that everything is out.

[oldjags]

I siphoned as much fuel as I could out of the tank, and then took a risk and used a wet/dry vac to suck out the rest. The last 5 gallons came out with a few gobs of goo. Then I vacuumed the entire interior of the tank. The only access hole is the 2" hole for the fuel gauge, so no way to scrub anything.

I thought about flushing with gasoline, but could not think of a safe way to suck it all back out again. I was already a little concerned about using the wet/dry vac with diesel fuel, but gasoline would have made me a sure candidate for a Darwin Award!

Hopefully I got all the big globs out, and the filters will catch the little stuff. I'll just have to check them every time we go out for a while.

[Laser fun]

Ditto our experience with a Hunter 35.5. Cheaper to empty the tank and recycle diesel and then siphon out corners of tank than to pay for a fuel polisher. Small fuel guage hole provided just enough access.

[Dolphin460]

I would purchased Starbrite Star Tron Fuel Tank Clearner. I have had similar problems and I highly recommend that brand. Then start using their Diesel Additive with every fill up. Not very expensive and it works.

[onavegador]

The ventilation of the tank was mentioned. But control also the intake of the fuel pipe in the tank (blow air throught fuel pipe), if your system has a shut off valve control if this one is not clogged, control if the valve is really open (I remember on my boat the valve was near the engine and warmed up during longtime running the engine, so a plastic part in the knob was aging and even the knop on open, the valve was still closed).
Good luck!
James