Author Topic: My turn for fuel system problems  (Read 647 times)

Offline relamb

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My turn for fuel system problems
« on: January 06, 2017, 10:48:35 PM »
Out sailing for a week, my engine stutters a couple of times during the day like it's going to die, but doesn't.
Anchored out, and then next day it ran fine for a half hour, then died for good.
The racor had a lot of crud in it, and although there was a lot of spare parts from the PO, there was not one of these seperator cartridges so we wiped the element  out as best we could with paper towels and changed the main fuel filter at the engine. Could not pull fuel up to the separator or engine filter bleeds, and determined it was the infamous clogged screen in the pickup tube.
Found a piece of copper ground wire long enough to ream it out, it was clogged with black goop.
Bled at the filter, and at the injection pump, but the engine would not run.
Sailed around for a couple days without the engine, until we could get back to the dock where I changed the racor element, and re-bled everything.
Still no start.  Fuel in the separator bowl appears clean.  Fuel at the main filter bleed comes out clean, as does the bleed at the injection pump.
I bled everywhere, perhaps a quart of fuel to make sure I had no air in the system.  No luck.
Cracked the fuel line fittings at the injectors, cranked the engine with the compression relieved, and nothing comes out of either injector steel line.
Any ideas?
Even if I still have air getting into the system, fuel should come out of the lines feeding the injectors, right?
I'm not familiar with how the injector pump works, could it be clogged?  Although the racor was nasty, the main engine filter did not appear to be, so I don't think anything got that far.  What are the odds the injector pump would die simulatneous with the tank  pickup screen becoming clogged?
Any ideas?    Vacations over, the boat will set for a few weeks in it's slip until I can get back with a plan.
Rick
CP16 CP23 CP27
Zionsville, IN

Offline deisher6

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Re: My turn for fuel system problems
« Reply #1 on: January 07, 2017, 09:50:13 AM »
Hey Rick:
My condolences.

 If you have not all ready removed the screen in the pickup tube in the tank I would recommend that you start there.  I was fooled into thinking that the fuel pickup tube in the tank was clear because I could blow through it and hear air bubbles in the tank.  The gunk was in effect a one way valve.  The tube unscrews from the fitting on the tank, filter is easy to remove.

There is also a screen at the bottom of the fuel pump.  I would check that after, checking to see if there is any fuel coming out of the pump.  At least two of us with similar problems replaced the fuel pump (unnecessarily).

Even though I emptied pumped all the old fuel out of the tank and started with fresh fuel when I purchased our boat, went through all the steps above, including learning how to bleed the engine real well.....I finally cleaned everything up starting at the tank.....it has now worked for three years with routine maintenance.

Your logic in tracking down the solution seems good.

I am interested to hear how you resolve your problem.

Congratulations  on sailing around for a couple of days without diesel power!

regards charlie

Offline BobK

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Re: My turn for fuel system problems
« Reply #2 on: January 07, 2017, 12:39:24 PM »
After checking the screen at the bottom of the fuel filter crack the line between the fuel pump and the engine to determine what side of the fuel pump the problem is located.  The electric fuel pump does a poor job of drawing a vacuum if there is air in the line between the now clean racor filter and the fuel pump.  I recommend installing an outboard squeeze bulb in the fuel line between the fuel tank and racor filter.  This makes bleeding the air out of the line simple.

If it pumps fuel you just need to crack the fitting at the top of the injector (only one at a time) until fuel seeps out.  If it does not pump fuel I would first make sure there is no air in the line between the tank and the pump.  If the pump is still not pumping fuel then recheck the screen in the tank and work your way back towards the engine.

The black slime is algae that grows in diesel fuel especially in the warmer climates.  You will need to add an algaecide to the fuel to kill this.  Pick it up at a truck stop.  Unfortunately this will probably clog the filter one or two more times until it is all out of the tank. Carry a couple spare filters.

Good luck...it can be a slow proceess to find the blockage.

BobK 

Offline Shawn

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Re: My turn for fuel system problems
« Reply #3 on: January 07, 2017, 08:56:23 PM »
Rick,

Make sure your engine cutoff isn't engaged, that would prevent fuel flow to the injectors.

After that...

How many bleed points do you have on your injector pump? My Lucas/DPA pump (Volvo MD7A) had three different places to bleed it as it was not self bleeding to the injectors. The first was to be bled by the lift pump, after that the next two had to be bled while spinning the engine by hand. If you have a decompression feature on your engine set that and then set the throttle to wide open which you try to bleed at your injectors.

In my case I could bleed to the first point (bled using the lift pump), bleed to the second while spinning the engine but couldn't bleed third or injectors it was because the injector pump seized. There is a high pressure plunger in them that can seize in the bore. I had this happen the day I bought my Sabre while the engine as throttle down after running beautifully for many hours.

This was with dual fuel filters inline with the engine and both looked like they were in good shape. I did have a somewhat clogged fuel pickup in the tank but never to the point that it had stopped all fuel flow.

I had another pump fail exactly the same way 2 years later during winter storage.

After that I pulled the inboard and went outboard.

It seems the ultra low sulfur diesel is pretty nasty to older injector pumps. It can develop diesel salts in the fuel which go right through filters and can cause all sorts of problems. That make have what seized my pumps and almost certainly was what were causing my problems with injectors sticking closed or partially opened.

Shawn

Offline relamb

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Re: My turn for fuel system problems
« Reply #4 on: January 07, 2017, 09:41:51 PM »
I am now 1100 miles away from the boat, back in the cold midwest, so I can't check anything.
I did verify that the screen in the pickup tube does act as a check valve when dirty.  I blew through it (backwards) and no problem.  Blowing the other way (from the pickup end, the direction fuel would flow) and it was clogged.   With the tools on board I could not get the 90 degree fitting removed at the top of the pickup tube, so I could not see if there was a screen in there, but something definitely stopped a piece of wire at least 1/2" short of going full up the tube. so I just kept jamming and twisting figuring I could tear up the screen.  Eventually I got enough gunk out (or ripped a hole in the screen) that it seemed to not be obstructing the pickup tube anymore. 
Fuel sucks freely into the water separator pulled in by the electric pump, and the bleed at the engine fuel filter pumps clean fuel without air bubbles, and so does the bleed screw on the injector.
As I said, I ran out about a quart of diesel total, pushed up by the electric fuel pump, so I'm pretty sure there are no obstructions in the fuel lines, and the electric pump is working fine.
>Make sure your engine cutoff isn't engaged, that would prevent fuel flow to the injectors.   What do you mean by cutoff?
I did have the compression lever pulled out, to relieve compression so I could crank for 10 seconds at a time with the lines cracked open at the injectors.
Does that kill fuel somehow?
Although the bleed on the injection pump bled fuel, closing that and bleeding at either injector got me nothing at all out of the injector feed tubing.

Rick
CP16 CP23 CP27
Zionsville, IN

Offline Shawn

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Re: My turn for fuel system problems
« Reply #5 on: January 07, 2017, 10:05:29 PM »
"Make sure your engine cutoff isn't engaged, that would prevent fuel flow to the injectors.   What do you mean by cutoff?"

Your injector pump has either a solenoid or a physical cable/lever on it that is used to shut off the engine. When that is engaged all it does is stop all fuel flow out of the injector pump. Make sure that isn't engaged as it would prevent you from getting fuel to the injectors.

"Although the bleed on the injection pump bled fuel, closing that and bleeding at either injector got me nothing at all out of the injector feed tubing."

If you are bleeding fine to the injector pump but not to the injectors your problem is at the high pressure fuel injection pump. Don't waste your time with the rest of the system, yet. If the fuel cutoff isn't engaged you have a failure in your high pressure fuel injector pump. What type of engine? If you are lucky spares are available or it can be rebuilt by a diesel specialist fairly easily.

If you do end up having to swap out the injector pump I'd *strongly* suggest also draining and pulling your tank and having it totally cleaned out. I didn't do this after replacing my first pump and that may have contributed to my pump failing again after a couple of seasons. And that was with a tank that wasn't fouling my filters like yours was.

Before pulling the pump make sure you check out how the injector pump is timed to the engine. You will want to mark the pumps orientation to the block to help you retime the engine when you reinstall it. The pump is typically rotated (like a distributor) to adjust injector timing. There will also be some sort of way of gross timing it to the engine. On my Volvo the pump was gear driven and the gears had timing marks that had to be lined up for gross timing. After the gears were meshed that way fine injector timing was accomplished by rotating the pump in its mount. Small movements made big changes. There are instruments available to help set timing but I set mine based on ease of starting and smoke after it was running.

Shawn

Offline deisher6

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Re: My turn for fuel system problems
« Reply #6 on: January 08, 2017, 09:26:45 AM »
Hey Rick:
Interesting lever on the Universal 12 control panel.   

I leave it closed when bleeding the fuel lines.

Under the heading 'Stopping the Engine', Page 11 paragraph 4 of the Universal Motors, Marine Diesel Owner's Manual:

"4.  To stop engine on Models 15, 18, 20, 30 & 40, hold throttle lever in the back position against the spring loading until the engine stops.   Then release the throttle from the stop position and throttle will return to the idle position.  Repeat if engine does not stop the first time.  Models 12, 25,& 50 have a separate stop lever for shutting the engine down."

I am not sure if the lever is a fuel cut off lever, a decompression lever, or both?

regards charlie

Offline relamb

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Re: My turn for fuel system problems
« Reply #7 on: January 08, 2017, 11:06:44 AM »
Mine is the Universal M12.  It has a T-handle cable that you pull out from the instrument panel to stop the engine.  It decompresses the engine, but I never really looked to see where it's connected to and what else it does, it may also do something to cut off fuel at or inside the injection pump.
I was trying to bleed with the lever pulled out (no compression) so the engine would not start up while bleeding.  Maybe it cuts fuel as well.
In which case now I do have a lot of air in the lines between the injection pump and injectors.

Rick
CP16 CP23 CP27
Zionsville, IN

Offline Shawn

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Re: My turn for fuel system problems
« Reply #8 on: January 08, 2017, 12:04:25 PM »
Are you sure that is a decompression lever? Usially they are a connection at the valve cover. Most engine stops are just a cable to the high pressure pump that turns off fuel.

If you were trying to bleed the injectors with the fuel turned off that explains why it didn't work. You would be able to bleed the rest of the system with that out.

Not a big deal if you have air in the lines. Just bleed it out if needed. Some systems self bleed the injectors.

Shawn

Offline Shawn

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Re: My turn for fuel system problems
« Reply #9 on: January 08, 2017, 12:10:33 PM »
Just checked and the m12 does not have a decompression lever. Just fuel cut off.

http://www.marinedieseldirect.com/universal/200157/universal-owners-manual-decompression-lever.html

So that is why you can't bleed the injectors.

According to this
http://www.marinedieseldirect.com/universal/200157/universal-owners-manual-bleeding-fuel-system.html

The m12 is self bleeding. So turn the fuel back on and you should be ok.

Btw, just in case, make sure your raw water input is closed. Too much cranking with that open can hydrolock your engine as it will be filing your water lift muffler as the engine isn't producing enough exhaust to push out the water.

Shawn
« Last Edit: January 08, 2017, 12:12:58 PM by Shawn »

Offline deisher6

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Re: My turn for fuel system problems
« Reply #10 on: January 08, 2017, 01:47:07 PM »

Again interesting. 

Has anyone changed filters without bleeding the system?

I have always bled the fuel lines.  The 'paper' operator's manual does not differentiate between engines in its bleeding instructions.  No pun intended! 

The M-12 diagram shown at the second of Shawn's websites shows two 'air bleed valves'.  They are the ones that I have always used.



regards charlie

Offline Shawn

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Re: My turn for fuel system problems
« Reply #11 on: January 08, 2017, 01:54:44 PM »
Sorry, when I say self bleeding I mean from the injector pump to the injectors. Some high pressure fuel pumps will self bleed there, some need to be bled at the injectors themselves. The Lucas pump on my old Volvo needed to be bled three places on the high pressure fuel pump and then to each injector themself. Later Bosch pumps for the same engine had to be bled to the pump but self bled to the injectors. There are probably systems out there that are totally self bleeding too, but I haven't worked on any.

Rick has already bled his system to the injector pump. So it it is self bleeding like that says then all he should have to do it disengage the fuel cut off (engine stop handle) and crank the engine and it should start up. Keep the raw water seacock closed. After the engine starts shut it right down again or open the seacock quickly.

If he wants to bleed to the injectors himself that should not hurt anything and it will of course help to verify fuel flow to the injectors.

As an example of a system that does not self bleed...

http://leisureowners.memberlodge.org/Resources/Engines/bl_md7a.pdf

Shawn
« Last Edit: January 08, 2017, 02:02:26 PM by Shawn »

Offline Allure2sail

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Re: My turn for fuel system problems
« Reply #12 on: January 08, 2017, 05:08:55 PM »
Hi Rick:
Jumping in here a little late but I'll add my two cents. The cone shaped screen filter at the top of the pickup tube should be removed. The tube itself I cleaned out with a rifle cleaning kit and some carburetor spray cleaner. Bought the rifle cleaning kit at Walmart. As some other people mentioned the shutoff lever should be pushed in because it will shut of the fuel supply. Don't know if it shuts the fuel off going into the injector pump or coming out, but the engine will never start with it pulled out. I hate to tell you this but the tank needs to be removed (my opinion) and cleaned. I have a post about that if you do a search. I cleaned my with gasoline and some carburetor cleaner. poured it into a coffee filter till it came out clean. it took half a dozen flushes with a lot of swishing around before it came out clean. The filter at the bottom of the lift pump is pretty useless. It is a lot coarser than the looses filter you could put on the racor so that screen doesn't do much. If it is dirty the racor filter must have gotten really clogged and the bypass kicked in. With all the info already given you and going back and reading my previous posts I'm sure you will get it fixed.
Best of luck
Bruce

Offline Shawn

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Re: My turn for fuel system problems
« Reply #13 on: January 08, 2017, 05:52:01 PM »
Hi Bruce,

" As some other people mentioned the shutoff lever should be pushed in because it will shut of the fuel supply. Don't know if it shuts the fuel off going into the injector pump or coming out, but the engine will never start with it pulled out."

The fuel coming out of the pump. Gasoline engines are throttled by controlling the amount of air going into them. Diesel engines are fuel throttled, they always have full airflow into them as they need it for compression ignition. When a diesel engine is idling it is basically at a very tiny percentage of its potential fuel flow (throttle) into the engine. Say 1%.  The engine shutoff (fuel shutoff) essentially just sets the fuel flow (throttle) to 0% so that no fuel is injected. With no fuel being injected the engine stops running.

Because of this it isn't possible to bleed the injectors with the shutoff engaged. Fuel is still passed into the high pressure fuel pump though so it is completely possible to bleed to it.

Agreed about pulling the tank and cleaning that all out.

Shawn

Offline Allure2sail

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Re: My turn for fuel system problems
« Reply #14 on: January 08, 2017, 07:05:00 PM »
Hi All:
This past August I had a fuel problem as mentioned in a previous post. To go through it once again. I thought I had taken out the screen the last time I had blockage (five or six years ago). I had stupidly put it back in the top of the pickup tube...mistake to say the least !! This time it happened I had a few gallons of fresh diesel in a fuel jug. Luckily had extra fuel line on board and ran the pickup fuel line from the racor to the jug with a weight on the end of the fuel line to keep it on the bottom of the jug. Engine started on the fresh fuel The primary and secondary filters were not clogged the screen in the tank was. Those Facet lit pumps are not that great on producing suction so the screen getting clogged stopped the fuel from being sucked out of the tank and through the racor. By placing the line into the jug of good fuel the engine ran. One thing I should have done (hindsight) was reroute the return line into the jug of fresh fuel as well. A diesel uses only a small amount of fuel it is feed and returns the unused back into the tank. If I had fed the unused fresh diesel back into the jug instead of the tank I would have had enough fuel to run at least for four hours (enough to get me safely home). Instead I ran the jug empty in 30 minutes. Lessons learned the hard way. Always keep spare diesel on board, keep extra fuel line on board of the correct size. Could be 1/4" or 5/16" check to see what size fuel line you have in your system and keep an extra four or five feet on board. The weight on the end of the fuel line placed into the jug was just a big nut held on with a cable tie.
Just an F.Y.I. on how you could keep the engine running and make it to safety.
I now have a much bigger racor filter setup and a vacuum gage on the outlet of the racor to tell me when there is a dirty filter element or restriction in the fuel line feeding the fuel
(Facit) pump. Hope I explained this clearly. If not don't hesitate to ask questions here !!!
Bruce
S/V Allure
« Last Edit: January 08, 2017, 07:06:41 PM by Allure2sail »