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Engine shut down while underway, need guidance

Richie 32-3

Member I
While motoring for about 2 hours in calm seas, no wind my 1989 Universal m25 Xp shut down. I was at 2200 rpm , about 5.9 knots the engine lost power, rpm dropped then went back up and down about 2 more times I throttled down but then the engine died. I tried to start it a few times with no luck. It cranked but wouldn't turn over. temperature gauges was in normal range , raw water was coming out and there were no alarms. 1/2 fuel in tank. Back at the mooring after about 1 hour since she shut down it started right up and appeared to be running normal. I didn't leave mooring since I didn't want to get towed twice in same day. Picked up a new racor 24s and the filter on engine, am I headed in right direction, any suggestions would be appreciated, thanks.
 

Loren Beach

O34 - Portland, OR
Senior Moderator
Blogs Author
Fuel Guessing

From the general symptom I suspect a minuscule air leak into the fuel system. This is sometimes called a vacuum leak, but others have questioned that terminology... no one has yet seen a puddle of vacuum around a fitting. :rolleyes:

I once found an air leak, by eliminating all of the other places. With the hoses all checked I deduced that it had to be an invisible air leak in the Racor (old factory 1988 filter, with the two O rings that have to seal perfectly when you replace the center filter section).

Darnedest thing is, that when not under suction, the "leak location" will not seep any diesel and reveal itself. :mad:

About a decade ago I installed a new Racor 200 series, with no further problem, and this spring I accompanied the engine replacement with a new Racor 500.
The 500 series has less places to leak air, plus it has more filter media in it.

Good luck on your search for the problem.

Everyone agrees that diesels are simple engines that only require fuel to run, but they are Mighty Darned Fussy about getting that fuel with zero air bubbles. :0
 
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Richie 32-3

Member I
Air leak?

Thanks Loren , can an air leak just occur, I have not done any maintenance in regards to fuel or filters prior to this and it's been running for about 50 hours so far this year with no problems, age of filters is unknown since I am the new owner of this boat.
 

Frank Langer

1984 Ericson 30+, Nanaimo, BC
I had the same problem as you described. I would bleed the engine, start fine, run 20 minutes, sputter for a bit and then die with no restart. I eventually traced the problem to the fuel pump which had a pinhole size leak, letting air in which stopped the engine. The only way to discover this was to run a new fuel line directly from the tank to the fuel pump, bypassing all filters, and then a fuel line held into a pail of diesel fuel. Pinhead sized air bubbles were barely visible in the pail of diesel fuel, but enough to identify the problem. A new fuel pump fixed it and it has been fine since.

You could also have a blockage in the fuel uptake in the tank, and air leak in the primary filter or elsewhere.

Good luck in figuring it out!

Frank
 

eknebel

Member III
fuel tank sediment

I agree with previous posts about fuel/air issues. Since you said it was a "new" boat, one thing to consider is sediment in the fuel tank. It is my experience that this buildup happens especially when the owner has tired of the boat(but hasn't sold it yet). This can cause repeated filter clogs as the boat gets used by the new owner(who0-hooo!) reoccurring until the sediment is cleaned out of the tank. The sediment/water also causes corrosion of the aluminum tank. You can have the fuel/tank polished, or drain the tank and fish around thru the fuel gauge port with a towel on a rod, fun right? Good luck!
 

Christian Williams

E381 - Los Angeles
Senior Moderator
Blogs Author
Does sound like classic fuel filter issue. Just change the filter--and keep spares aboard.

As Loren suggests, vacuum leaks are usually the culprit if problem persists.

If the Racor unit is factory equipment, it is far past service life by now. They must seal well and have no hairline cracks--such matters are basically invisible-- and since it's only a couple hundred bucks a whole new Racor unit eliminates doubt.
 

JSM

Member III
Had the same problem this past week. Had water in my fuel tank due to leaving the cap off. Solved the water problem , bled the engine and then discovered that the engine would not go over 2200 rpm. Turned out that the Racor had developed a leak at the bleed screw on top of the housing. Replaced the Racor housing and the fuel pump as they were both original to the boat (87). Now running better than ever.
 

Richie 32-3

Member I
Found bleed knob not closed fully

Finally got back to the boat today. Changed the fuel filters, primary racor was impossible to drain due to location so I just removed the whole filter and bowl using a large ziplock bag to catch the fuel, it worked out well. The bowl had a good deal of sediment and crud in it which I assume probably caused the shutdown. Used bleed knob and after about 8 minutes running that fuel pump I started engine and it ran well. On a side note I found the bleed knob a little loose, it was not shut tightly maybe a quarter of turn open, is this normal or should I tighten this up I left it the way I found it, I thought I saw a thread where someone spoke to westerbeke and were advised not to shut that knob tightly, what do you guys think? Thanks for all the help , going out tomorrow for a full shakedown cruise.
 

markvone

Sustaining Member
I just tighten the bleed nut until it's snug. If it's running fine and not leaking at the bleed nut you are fine.

Mark
 

Kenneth K

1985 32-3, Puget Sound
Blogs Author
Last month, I encountered the same problem that the original poster had.

It all started after I pulled my aluminum fuel tank and rigged a temporary tank in its place, so I knew right away it was all fuel/leak related (I.e., clean tank, new fuel, new filters). Each time the engine quit, I'd run below deck and bleed off some air through the fuel bleed knob, and the engine would start again within a few minutes.

By about the fifth time it happened, I could catch it before the engine actually died--I'd just crack the bleed valve a bit, and the engine would slowly come back to life.

Eventually, I figured out I could just run indefinitely with the bleed knob open about 1/16 of a turn.

That's still what I'm doing a month later. I'm guessing it's a vacuum leak, like Lauren described above, in any of the supply-side fittings I changed when swapping tanks. I have a new facet pump and a new fuel return line ready to go. I'll probably change the location of the engine mounted fuel filter, too, along with reinstalling the factory tank. So, I'm delaying further troubleshooting till after those things are done. But it's nice to still have an operable engine, even if in a temporarily dergraded condition.
 
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supersailor

Contributing Partner
I had this problem drive me nuts for awhile. By bypassing the fuel filter, using a bucket of fuel, I figgured out the fuel filter was the culpert. An inspection of the filter revealed a crack in the aluminum housing letting air into the system when running. It did not leak when shut down. Several other people remarked on the issue.

If my filter was older than about 7 years old and I started to have problems, I would replace it. The consequences of a shut down are severe enough for the cost to look small and the peace of mind to look high.
 

Alan Gomes

Sustaining Partner
I agree with previous posts about fuel/air issues. Since you said it was a "new" boat, one thing to consider is sediment in the fuel tank. It is my experience that this buildup happens especially when the owner has tired of the boat(but hasn't sold it yet). This can cause repeated filter clogs as the boat gets used by the new owner(who0-hooo!) reoccurring until the sediment is cleaned out of the tank. The sediment/water also causes corrosion of the aluminum tank. You can have the fuel/tank polished, or drain the tank and fish around thru the fuel gauge port with a towel on a rod, fun right? Good luck!
Concerning sediment in the tank, one thing I'd suggest is seeing if you can remove the pickup tube to check whether there might be a screen mounted on the bottom of the tube. If there is, remove it. You really want the fuel filter to pick up the crud from the tank, not have it blocked by a screen. Also, some electric fuel pumps also have a built-in screen. Check that as well.

As for the problem with the fuel filter: I just replaced my Racor 120 filter with a Racor 500MAM. Yes, some would consider this MASSIVE overkill for a little 7 hp Yanmar 1GM! (The fuel filter is almost as large as the engine! :nerd:) But: (1) The filter is much more robust than a 120 and less likely to develop leaks in the housing, as has been mentioned. (2) Filter elements cost half as much (~$10). (3) It is waaaaaaaay easier to change filters. You could do it under way (in reasonable conditions) without slopping fuel all over your engine compartment. No way with the 120; it's easy to make a mess even when you are tied up to the dock! (4) It has huge filtering capacity, both for crud and for water separation.

The main downside is the cost. I managed to find a really nice used one on eBay (the MAM model with the metal bowl) for $90, including a new filter and vacuum gauge. These are fairly bullet proof, so I would not worry about buying a used one. Just keep your eye peeled and be ready to jump on a deal when you see it.
 

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