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[WFP]

Was taking some friends for a cruise yesterday and had an problem with one of my engines.  Cat 3126TA 350HP.  Was cruising at 2300 rpms for about 10 minutes when I started to lose power in the port engine.  I thought I caught the line of a lobster pot.  I got really concerned when it showed zero oil pressure so I shut it down.  After returning to the dock...hobbling, I opened the hatch worried that I would see the bilge full of oil...luckily, it was clean and all looked fine.

I primed the engine and it fired up but sounded bad...due to insufficient fuel.  I primed it again and it purred like the kitten it normally is.  Was able to go out again and had a good time but I would really like to know why it happened!

Any thoughts on the cause?  I have racor filters, they were clean and there was no water.

How could I have gotten an air pocket in there...any thoughts?

[BLM777]

WHP....catch HUB online or PM him.  He would be my first choice on any diesel problem as he see's it all....everyday.

[HUBBARD]

Check your fuel supply, and return lines.  I'm bettin' you'll find a loose fitting.  Also, you should have an Engine Diagnostic Screen on your instrument panel.  Did it display any codes?  If you don't find any loose fuel lines, you probably have an electrical problem.  Could be as simple as in the connection to the ECM.  Your oil pressure dropped because that gauge is more than likely, electric.  It dropped when the motor started dying.  Don't take my comments as gospel, either.  I'm not a certified CAT technician.  No Rookie, either!  Just sharing my experience over the years.  Later--HUBBARD        

[reo]

That engine came in mechanical and electronic heui form. If its a heui and the oil pressure fell below spec with above idle speed you would have generated a fault or event code. My guess is as hubbard said your oil pressure fell because the engine was below idle speed.

You could be sucking air in your fuel system. In addition to checking for loose lines check your racor filter housing for problems, you could bring fittings to bypass it if it happens again. I found a cracked stand pipe on my buddy's Viking once causing the same kind of problem, very difficult to find. If it has a hand primer the valves could be bad. You may even want to check fuel pressure at speed.

[arcticdude]

It also could be as simple as the oil pressure sending unit going out.  That would explain the apparent loss of oil pressure and the engine quitting.  On the electronic engines, if the computer senses low oil pressure, they'll shut off the fuel flow until the oil pressure situation is resolved.  Computer doesn't know if the sending unit is bad or there actually is no pressure.  Do both engines draw through the same fuel line all the way to the tanks or is there a common line that splits just before the engines?  Common line would essentially eliminate most of the fuel system as having a problem, since the other engine was fine.  Gotta love twin screws.

[WFP]

Thanks guys!  These are NOT the electronic versions, they are mechanical, turbo-aftercooled with engine heaters..  Pretty simple actually.

I wish I paid more attention when I checked the Racor...I didn't notice if it was loose!  I had the marina do the winterizing so they may have done just that and left it loose enough for air to get in...but I really did not notice.  I also did not notice any fuel leaks around it.

I will do a more thorogh look at the oil lines but I do believe it was fuel related.  Anyone that has ever heard a diesel running out of fuel would recognize the sound...loud marbles banging around is all I can equate it to.

With a (pardon the pun) boatload of people aboard, I did not hear it originally running out of fuel...only after the first time I primed it.

Thanks again!

/Bill

[WFP]

It also could be as simple as the oil pressure sending unit going out.  That would explain the apparent loss of oil pressure and the engine quitting.  On the electronic engines, if the computer senses low oil pressure, they'll shut off the fuel flow until the oil pressure situation is resolved.  Computer doesn't know if the sending unit is bad or there actually is no pressure.  Do both engines draw through the same fuel line all the way to the tanks or is there a common line that splits just before the engines?  Common line would essentially eliminate most of the fuel system as having a problem, since the other engine was fine.  Gotta love twin screws.

Separate lines from two tanks, two racor filters.  I can draw either engine from either tank...both were filled at the end of last season and treated...this was the first run for the boat.

/Bill

[porthole]

I wouldn't trust the yard completely.

Pop the tops off the racors (close the valves first if you have them) and check the o-ring, easy for it to drop out of the groove when re-installing.

Did you check the primary spin on too?

[WFP]

I wouldn't trust the yard completely.

Pop the tops off the racors (close the valves first if you have them) and check the o-ring, easy for it to drop out of the groove when re-installing.

Did you check the primary spin on too?

Thanks...I wish I had more time to do my own work!  The yard has been known to break a few things...

I did not check the primary fuel filter...other than visually for leaks and it was tight...I could not turn it with my hand.

Good thought on the o-ring...will check this week...of course...since I had it open already once...mow it would be my fault!

/Bill

[porthole]

Another thing I just thought of, and this has happened to me four times, twice on boats and twice on a new $650,000 ladder truck!

Turbo hose, from the turbo to the intake, or somewhere along the "pressure" side of the turbo to engine intake piping.

3 of the times the hose just popped off, one time there was hole, very narrow and about an inch and a half long, caused by a poorly place hose clamp.

On a turbo engine, without the boost the things run like crap, lot of noise and no power.

Good luck.