Perkins Problem

[terry_thatcher]

I have a problem with the perkins. I am going through fuel filters ever couple dozen hours. At least, I thought that was the problem. The vacuum gauge would suddenly peak, the engine rev, then die. I would replace the main filter, prime the engine, and everything will be fine for another few dozen hours. But then I spend $350 to have the tank cleaned and the fuel polisher said--"I can't find any dirt. My filter is still clean." And then, 20 hours later--engine dies just as before as if the filter is clogged. Filter doesn't look dirty, by the way.

Now someone has suggested that I might have a plugged up fuel air vent line. I know it is not plugged at the tank, but I have not followed it all the way to the back of the boat yet.

Any other thoughts? Otherwise, Perkins runs like a dream.

 

[tfrere]

Try running it with your fill cap off on your deck fill. If the air vent line is plugged, you will get air into the tank from the deck fill and you should not get a vacuum.

 

[larryhume]

Terry,
As you know, three things will stop a diesel. Air, water, or dirt. You have eliminated dirt. Perhaps after a few hours of running the heat build-up and vibration causes a pipe or fitting to expand allowing air into the system. There might be a questionable gasket somewhere. Tough item to track down. Maybe an old hose clamp has caused a slight crack, and heat and vibration opens it just enough to cause your problem. I would start replacing cheap, easy to get to hoses, clamps, fittings and see what happens.
Good Luck
Larry

 

[tdenney]

Terry,

This is a real long shot, but I will toss it in the mix. A friends boat, a 1993 Compac 33, had similar symptoms. His tank pick-up tube had a screen at the bottom end, installed by the builder. It would slowly clog up and the engine would starve after running for six hours or so.

The crud never got to the filters, so they looked good. When daysailing, the problem never showed up because he did not run the engine that long. At the dock, I guess the crud kind of fell off the screen. We were blindsided by this problem halfway back from the Bahamas.

I doubt that you have this problem, unless there has been a retro-fit along the way. I'm pretty sure Morgan didn't put a screen on the tank pick-up. Still, it could be some kind of pick-up tube blockage. If the pick-up tube has crud in it, I don't think polishing the fuel will clean it out.

Tim

 

[bwilliams]

I had a similar problem and finally determined that the check valve just at the entrance to the Racor primary filter was essentially fully plugged up. The engine shutdown wasn't consistent as far as timing, but was very random. My boat is 30 years old and I don't think the check valve had ever been removed and cleaned. No problem after cleaning it.

 

[solo2]

Hi Terry,
How old are your fuel lines? Time to replace? There may be a piece of inner liner flapping around. The fact that your vacuum goes up rapidly tells me that it is not dirty fuel, also my check valve is on the inlet to the lift pump, clean fuel.
Tom

 

[maluhia]

Also check the fuel pickup pipe and possible sludge at the bottom of the tank. The vent and return line need to be clear. Sludge is especially a problem when the boat is motion and under power.
Jim

 

[terry_thatcher]

thanks. I had the tank cleaned out and the fuel polished. I am going to work on the vent next--I can't blow through the hose, but then, it is 15 feet long. The old vent in the back may be plugged, however. I will be replacing my fuel hoses to the engine as well.

 

[tdenney]

I recently found about a quart of diesel in the drip pan after a day sail. Only ran the engine about an hour. Pan was cleaned out recently before that. I thought it was the Racor leaking since it is pretty old. Unfortunately, that was not it. It appears to be the injection pump. It is definitely not oil, pure diesel. I started the engine and watched it drip about two drops per second. This looks like a real pain. Anyone run into this before?

 

[chawakee]

Just went thru the same thing with my 4-108. The high pressure fuel lines are really tough to get at, as is the injector pump. If you can look around with a mirror and ID the leak point, and not the drip point you will save yourself all sorts of time. My leak point was the third cylinder, that's bow to stern, number one being the bow, number four the furthest aft. The actual leak was the fuel line connection to the injector pump. First drain the coolant, there's a spigot starboard side just below the manual lift pump, I used about six feet of clear hose and drained it into a gallon jug at the low point in the bilge, the one with the dust pan, you only need to drain out enough so the coolant water tank is empty, about three quarters of a gallon. Remove the water tank, two bolts on top of tank, actually, one nut, one bolt, then one short hose connection on the port side of tank, totally remove both hose clamps, on the starboard side top of tank the overflow hose slips right off too. With the tank removed you will see the thermostat, I changed mine, it pops right out. Next remove the starter motor, now you will have full accesses to the injector pump and fuel lines. Its a lot easier than it sounds. I had ordered a full set of fuel lines some years ago, so I had what I needed on hand. PS, I replaced the water temp sensor too, it has a wire connector on top, it sits just aft of the thermostat and is impossible to get at unless the water tank is removed. Good luck.
Robert McCabe
Cha-Wa-Kee
M 382.
Build # 169
1979.

 

[tdenney]

Robert,

Thanks. It sounds like you have the separate header tank and heat exchanger. I have the single combined unit on the port side (which I don't like so much). I looked and looked with the engine running, and finally determined that the pump itself was leaking as well as one cylinder tube attachment. It literally leaks a quart in five minutes.

My mechanic said that with that much leakage, I probably I needed a rebuild. He thinks the new low sulfur fuel is rough on the original seals. Well, maybe. We also discussed the possiblity of switching to a separate header tank and heat exchanger. We'll see if he has the parts in his "bone yard".

The engine has 4700 hours on it so I have rationalized a rebuilt pump for about $400 and probably that much in labor. If, in the future, I decide on a rebuilt engine, I will already have a pump.

I will drain the coolant, disassemble most of the stuff, then let my mechanic remove, rebuild, and reinstall the pump. Then I can reinstall everything else and save some labor cost. This is also a good time to pull the injectors and flush the cooling system. As usual, there will be something else in there that I don't know about yet.

Thanks again.

Tim

 

[bwilliams]

Had the same general type of problem with a substantial leak at the anti stall device. Had to rebuild the injection pump. My cooling system is the same as yours, and all that system had to come off to remove the injector pump.

 

[tdenney]

Thanks Bill,

I have been talking to people in the marina. Everyone (gas or diesel) is worried about changes in fuel formulation. Gas users are worried about ethanol, diesel users are worried about low sulfur diesel, etc. I still wonder if the new diesel caused this problem or was it the 4700 hours of run time?

I am seriously considering changing the cooling system to the separate header tank and heat exchanger. The existing arrangement makes it too difficult to access anything on the port side of the engine.

Another consideration is the cost of the combined manifold/heat exchanger. Once I convert, I can plumb any heat exchanger into the system as long as it is big enough. Can't be too big. Right?

Has anyone made this change? How bad was it?

Thanks again.

Tim

 

[yurek]

Tim wrote here:
This is a real long shot, but I will toss it in the mix. A friends boat, a 1993 Compac 33, had similar symptoms. His tank pick-up tube had a screen at the bottom end, installed by the builder. It would slowly clog up and the engine would starve after running for six hours or so.

The crud never got to the filters, so they looked good. When daysailing, the problem never showed up because he did not run the engine that long. At the dock, I guess the crud kind of fell off the screen. We were blindsided by this problem halfway back from the Bahamas.

I doubt that you have this problem, unless there has been a retro-fit along the way. I'm pretty sure Morgan didn't put a screen on the tank pick-up. Still, it could be some kind of pick-up tube blockage. If the pick-up tube has crud in it, I don't think polishing the fuel will clean it out.

I have the same problem, I had clogged pick up tube. Blew compressed air in the tube, clean it polished the system and after ~100 hrs tube cloged again. I know that for sure because I have vacuum gauge and double fuel filters in fuel system.
Question: how to remove pick up tube ? Is it threaded in to the plate or just have two nuts to hold it to the plate. Can I remove it thru fuel gauge opening? Did anybody have seen the tube ?
Does it has a screen?

 

[terry_thatcher]

Yurek: That was a very late comment. My 2011 problem, which I guess I never reported back on, turned out to be a collapsed air vent hose.

 

[yurek]

Thanks Terry, I need to remove pick up tube and you describe problem which exactly I have.

 

[royaltern]

Many years ago, my perkins would not start, lack of fuel. mechanic pulled pickup line. There was a cloged screen on the bottom. Took screen off and never had that problem again. Boat a morgan 383.

 

[yurek]

I find that Pick up tube can be removed from the top of the tank it has 5/8 NPT thread in the cover plate. Line was clogged.
I add second pick up line which I will use for fuel polishing.

 

[Pbenoit]

Hi Terry, I had a very similar problem with my 382/4.108 (original engine, original fuel tank). Although I do not have a vacuum gauge installed and my engine never stalled out (just complete loss of power, as would be expected with clogged filters), a lot of what you say is familiar to me.

Like you, I (first) replaced filters, to no avail. I also replaced my lift pump, which no one here seems to have mentioned yet: if the lift pump is failing/failed the high pressure pump will likely have trouble lifting all the way from the bilge tank even with the tightest system, and most likely find. way to suck-in air somewhere.

As far as air leaks: in replacing the lift pump I found (estimated) that it had been replaced fairly recently by a previous owner and it was functioning properly. HOWEVER whoever replaced it that had *failed" to appreciate a rather unique compression seal configuration on Perkins and Westerbeke's of a certain age. See ATTACHED PICTURES Perkins part number is 33811113, also as Parker 60VLV-4 and sometimes called a ferrule, olive or Vibr-Lok. These rubber rings often remain (unnoticed) inside female fittings when fuel pipes are removed. They should be BETWEEN the flare and the compression nut, see pictures.

This led me down an (above-mentioned) rabbit hole of things to do with air leaks and the anti-stall aspects of the high pressure pump.

My low power problem remained! At this point I was convinced it was a debris in my fuel tank clogging the line. I eventually removed the access panel/manifold plate and while there was not much sludge, I DID FIND A PIEE OF DEBRIS that I suspect had intermittently been draw up against the pickup tube and was to blame! It almost certainly had been introduced via the deck fill. LESSON: be careful when fueling!

NOTE: In the interim of finding time to clean the tank (which is not fun or easy due to baffles and the small access plate), I found a TEMPORARY FIX: I would (1) close the fuel shutoff valve at the tank, (2) open my racor filter housing, (3) open the fuel line valve and allow fuel to flow from the filter housing back into the tank, (4) close fuel shutoff valve, (5) use my spare fuel jug to refill the housing + repeat steps 3-5. This seemed to dislodge the debris and give me full power until that evil little piece found its way back to the pickup tube. It lasted anywhere from 20 minutes to 10 days!