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View Full Version : 6V92 stalled - need advice asap



bobk
05-13-2009, 06:05 PM
Hey guys, I need some fast advice.

I'm cruising north and lost one of the 6V92's in the Alligator-Pungo canal (NC). It sounded like lack of fuel when it went down. It restarted once and ran a few minutes and stalled again. I tried priming with the electric pump and no luck. We limped back to Dowry Creek marina in the middle of nowhere only to find the only mechanic within 100+ miles is away until Sunday. I'll R&R the fuel filters in a few minutes, but am not hopeful They only have a few hours since the last change and both fuel deliveries were from sources that are known to be fresh.

Any ideas on where to look? All ideas appreciated.

Bob
Chateau de Mer
1981 48 MY

Avenger
05-13-2009, 06:19 PM
How long did it sit before you tried the re-start that was succesful? If it sits for a while, let's say 15 minutes, and seems okay for a bit then stalls again I would suspect fuel restriction. If you have a hand primer you can usually feel pressure when on a pumping stroke, and/or vacuum on the suction stroke. If you feel heavy vacuum it's a restriction. If you can never get pressure it may be an air problem. Do you have any clear tubing aboard?

Other than that go with the basics. Is it definitely drawing from a full tank? Are the shutoffs in the proper run position, no issues with solenoids? Does it stall in gear, but run in neutral? If so, can you turn the propshaft by hand?

Just some ideas, not easy to do diagnosis from 1000 miles away. :)

Good luck and I hope this helps.

captddis
05-13-2009, 06:41 PM
Make sure you change the secondaries too.

Canuck Dennis
05-13-2009, 07:17 PM
Check for a faulty fuel pump also, not sure about the 6-92 series but on the 12v series you can put a small mirror under the pump and check if it is turning,
you can also remove the return line to see if fuel flowing there.
may also be a stuck injector although fairly rare happening.

Genesis
05-13-2009, 11:58 PM
Probably a fuel restriction or air leak somewhere.

Open the Racor (if you have those) and see if there's fuel in it or air. If fuel, odds are its a restriction. Do you have vacuum gauges on the RACORs?

If the fuel pump itself is hosed (it CAN happen) the engine will not run at all; you HAVE TO have positive pressure in the rail or it won't start.

That it starts and runs for a while strongly implies either a suction-side restriction in the fuel line (a blob of crap that got sucked into the pickup, for example) or an air leak somewhere, and a fairly bad one too if it killed it entirely.

A stuck injector won't keep the engine from operating at all, although it will run like hell with one cylinder not firing - but it will run.

Pascal
05-14-2009, 08:37 AM
i agree with the secondary, how old is it?

check the priming pump to make sure it's actually pumping, most electric pump have a screen on the inlet side that can get dirty. it's easy to pull the outlet side to make sure you have flow.

I believe that if the engine fuel pump was bad, the engine woudl run on the priming pump if you keep it on.

obvioulsy, try switching tanks on that engine...

bobk
05-14-2009, 09:11 AM
It looks like there is a pluggage at the fuel supply selector valve before the priming pump. The pump will not run on either tank. If I break the supply line to the pump it sucks air good. The Racor was down about one inch when I opened it.

I'm now trying to pull the square pipe plug on top of the valve to see if I can clean out any crap in it. It's a bi@@h to open it! Any other ideas? The location makes it real hard to pull the fuel lines to and from the valve and it is lower than the top of the tank so fuel might siphon out. The fuel supply diagram doesn't show a valve on top of the tank at the dip tube.

Bob

bobk
05-14-2009, 09:14 AM
I forgot to add that both primary and secondary fuel filters were changed in March.

Bob

captddis
05-14-2009, 09:24 AM
Did you check the check ball in the racor?

Genesis
05-14-2009, 09:29 AM
Bobk, find someone with a vacuum tank, connect to the OUTLET side of the RACOR and pull a full vacuum on the line. It will PROBABLY pull through. Get a REALLY GOOD vacuum pulled and hit it "all at once"; don't open that valve slowly, slam it.

You can blow it out with compressed air but that doesn't help as the glob will go back into the tank and plug it up again!

bobk
05-14-2009, 10:16 AM
Good thought Karl. I just checked with several places and services in Bellhaven, NC and no one has anything, pressure or vacuum, so I'm going to try to disconnect the lines to the selector valve and run a small snake through them.

Bob

34Hatt
05-14-2009, 10:26 AM
Do you have a dinghy pump or air pump for rafts. I use that in a pinch to get home. Turned out it was a bottle cap in the bottom of the tank :(
So vacuum doesn't always work.
It was in there a long time and then found the pickup tube ;)

mobilemn1
05-14-2009, 10:43 AM
Bob,

If you need any further assistance let me know, I can get air to you in about 45min. I am in Williamston and that is how long it would take me to get to you. I have a small air tank if that would help and probably any tools you may need.

Let me know.

bobk
05-14-2009, 12:23 PM
Well, I'm now more confused.

I broke the line from the selector valve to the priming pump and fuel siphons easily from either tank so I now believe there is no blockage in the valve. When I run the priming step, the pump runs a few seconds and then slows to almost stalled. I guess it is possible I have a bad priming pump, but I don't like coincidences. I also broke the line to the Racor and ran the priming pump and no fuel flowed. I put a snake through the hose and it was clear to the first metal elbow.

What's left. Engine fuel pump? There is a sensor of some sort on the secondary filter. Could this be involved?

Does anyone know of a DD mechanic anywhere near Bellhaven? The marine engine guy that the marinas use is away for several days.

Again, many thanks for all the advice and offer to help.

Bob

mobilemn1
05-14-2009, 12:48 PM
Bob, give me a call 2522176558, trying to find you some local help

Timm
05-14-2009, 12:55 PM
I have 8v71's and had a similar problem. What I did to prove and or eliminate different components follows below. I think the sensor on the secondary filter housing you are referring to is the pressure switch that when fuel is flowing, closes and provides voltage to the engine hour meters.

The following process is to eliminate non-engine components. The concept is to bypass any exterior fuel components and to see if you can get the engine to start and continue to run from a portable fuel tank.

- remove the sensor/pressure switch on the side of the secondary filter housing.

- rig yourself up a 3/8" brass barbed connector and screw that into the filter housing where the pressure switch was. Don't worry about gooping up the threads since it's just a temporary connection.

- get a 36" piece of 3/8" clear hose and a couple of hose clamps

- attach the piece of hose to the barb with clamps

- get a 5 gallon tank of fresh fuel

At this point you need to try and force as much fuel into the secondary and the fuel rack. You'll feel some back pressure as it gets filled up. You might save some time and remove the secondary filter element and fill it up as much as you can before forcing the fuel into the engine.

Make sure the fuel hose is filled with fuel and then put the open end into the fuel tank keeping the other end attached to the secondary filter.

See if you can get the engine to start and keep running with this set up. Keep in mind that 5 gallons of fuel will go pretty quick. You should be able to see the fuel flowing through the clear hose.

A Detroit Diesel mechanic told me about this and said: if you can't get these engines to run out of a portable tank, there is something internally wrong. Fuel pump, plugged injectors, etc.

If it does start and remains running, you've eliminated fuel related componets physically on the engine.

doc g
05-14-2009, 12:58 PM
The "sensor" on the secondary fuel filter canister is for the Hobbs meter ,hour meter. I would avoid breaking lines apart and get a vacuum on it as Karl said . If you blow it thru you'll end up with it clogging up at the worst possible time ,remember Mr Murphy?? Try a shop vac or one of those small DD primer pumps hooked to the line to provde suction . It also sounds like your prime puymp may be bad . The more lines you open the more possible air leaks ...............Pat

bobk
05-14-2009, 01:04 PM
Tim, how do you pressure the fuel into the secondary?

Bob

doc g
05-14-2009, 01:13 PM
Bob , I've used a el cheapo fuel pump from Trac Auto with fuel line on it . Tap into the system wherever there is a pipe plug (usually at the secondary fuel filter housing) and use a gas can of diesel , I plumbed the fuel pump with a fitting that fit right into the secondary filter housing ( the pressure side of the pump to the filter housing )and used alligator clips on the leads to a 12V source. You can prime the filter and the rack with that . I did it on my old boat every filter change . ........Pat

Genesis
05-14-2009, 02:01 PM
The secondary filter is under PRESSURE - about 60psi - when the engine is turning! CAREFUL! Spraying fuel is at minimum a hell of a smelly mess.

You can stick a HAND PUMP suction side on the outlet of the RACOR (detach the fuel line going to the fuel pump from the RACOR) and pump. If fuel flows you've eliminated from the tank to the fuel pump on the engine.

If that test passes it is VERY LIKELY the problem is the engine fuel pump.

That pump is a little gear pump with an integral relief valve that controls pressure. It has VERY tight tolerances internally but is mechanically a very simple device. If the relief valve sticks open it will produce essentially zero pressure and the engine will run like crap, if at all. This is an unlikely but possible failure mode, but if you can draw fuel through the filter using a hand pump...... BTW beware rotational direction if the pump is bad when you go to replace it.

The more likely given the symptoms, as noted, is that there is a restriction in the suction side of the system. You have to either find it and mechanically remove it or suck it through. If you blow it back into the tank it WILL bite you again. If you need to go NOW and can take that risk detach the INLET side of the RACOR plumbing, attach compressed air, and blow backward towards the tank. The heavy copper used by Hatteras from the factory is rated for refrigeration-style pressures, so putting 50psi or so on it is no big deal. BUT - all that does is blow the crap back into the tank!

The ideal fix is a vacuum tank. Detach the OUTLET of the RACOR, attach the vacuum tank TO the RACOR, and slam open the vacuum valve. This SHOULD drag whatever is plugging the line into the RACOR where it will be trapped, and solve the problem. If it fails you're no worse off than you were before, as a full vacuum is only 15psi, so the option to blow it backward still exists.

Another option, assuming you do not think the problem is in or on the pickup tube, is to detach the fuel line from the tank, put a hose on it to direct it into a catch can, then apply air pressure BACKWARD from the RACOR toward the tank. This will expel ALL the fuel in the fuel line into the catch can - along with whatever is plugging it up. This will not work obviously if the obstruction is in or on the pickup tube.

Getting the pickup tube out of the tank is a real pain in the ass. It can be done, but its not easy.

BTW I am assuming you have checked the RACOR bowl and it is not full of water, right? RACORs have a floating ball in them that will shut off the fuel (intentionally) if the bowl fills with water.....

captddis
05-14-2009, 04:04 PM
First did you CHANGE the sec filter? March does not mean much. Run a hose from the secondary filter of the running engine to the other secondary, run the running engine and it will prime the dead engine. Then while one engine is running start the non running engine. Both should run. If the bad engine is out I would suspect a broken blower drive. The fuel lines and tubing is 5/8. i have never seen one of those lines plug up.

Genesis
05-14-2009, 04:55 PM
I have (seen the fuel lines plug up) - MINE did, forcing me to come in on one engine.

My recommendation on the vacuum tank is from personal experience :D

The secondary has to be VERY plugged for the engine to not to run at idle. When the secondary gets loaded it will start to misfire at higher power levels as there is insufficient fuel pressure in the rail with the consumed fuel; this limits output but won't shut the engine down.

doc g
05-14-2009, 04:55 PM
Dave, great idea!!!! I like that one ,good to know if you ever have a fuel pump die. I think I'll make up a line with the fittings just to have it onboard........Pat

captddis
05-14-2009, 05:02 PM
I have (seen the fuel lines plug up) - MINE did, forcing me to come in on one engine.

My recommendation on the vacuum tank is from personal experience :D

The secondary has to be VERY plugged for the engine to not to run at idle. When the secondary gets loaded it will start to misfire at higher power levels as there is insufficient fuel pressure in the rail with the consumed fuel; this limits output but won't shut the engine down.


Well I HAVE seen engines not run because of the secondary. Do you have to dispute everything??

mobilemn1
05-14-2009, 07:13 PM
Bob, just wanted to check to see if everything was still running ok,,,and did you find the filters that you needed.

It was nice to meet you guys, hope you have a nice pleasant trip the rest of the way home.

Pascal
05-14-2009, 08:36 PM
if your genny has an electric lift pump, disconnect it's output and run that to the DD secondary inlet. turn on the genny lift pump to prime and then crank...

sound crazy, but i did that once to get home...

that will eliminate any doubt about the engine (except the fuel pump...)

or if you want to use that to prime the system, connect the line to the primary inlet...

mobilemn1
05-14-2009, 10:59 PM
Bob,

Maybe on your next stop along the way, see if you can find some FFPF, it
is in a small white bottle with a red and green label. If it was a water problem that you had today, that will bond the water with the fuel to help burn it on out. Add about 3 bottles to each tank, what the filters don't catch you should be able to burn. If it was trash, then you should have enough filters with what you picked up this evening to see your way home.

Happy boating

34Hatt
05-15-2009, 08:28 AM
Bob,

Maybe on your next stop along the way, see if you can find some FFPF, it
is in a small white bottle with a red and green label. If it was a water problem that you had today, that will bond the water with the fuel to help burn it on out. Add about 3 bottles to each tank, what the filters don't catch you should be able to burn. If it was trash, then you should have enough filters with what you picked up this evening to see your way home.

Happy boating


Oh Boy now you did it hold on to your Shorts!!

bobk
05-15-2009, 10:08 AM
I tried to get this off earlier but was out of Verizon range.

So here is the scoop. We are underway this morning and have made about thirty five miles. The engine seems OK.

First, many thanks to everyone who helped and a special thanks to Darryl Hollis (mobilemn1) who drove about 45 minutes to help in person. This forum has a great bunch of people.

Darryl brought a fresh set of eyes and we did a few more diagnostic things then decided WTF, lets change the Racor. I primed the system with fresh fuel from a jug, it started and ran at the dock, but was erratic and almost stalling at idle. We had to drive into Washington about 30-35 miles away to get some secondary filters and after changing the secondary (again primed from a jug) the engine started on the second try and kept going after it pulled the air out.

Boy am I red-faced. When it first quit my inclination was to change filters but then I got hung up on the apparent blockage at the priming pump. That led me on a wild goose chase that should not have happened. I’ll pull the pump and either service it or replace it when I get back to a marina again. Lessons learned, … try the easy stuff first, and allow for coincidence. I’ll also make up a long fuel hose that will let me prime either engine with either pump.

Bob
Chateau de Mer
1981 Series I MY

Genesis
05-15-2009, 10:33 AM
How long had it been since the secondary had been changed?

Its certainly possible for a plugged filter to do this but the secondary has to be REALLY plugged (since its under ~60psi) to refuse to run at idle where actual fuel demand is pretty low. I've seen this happen a fair bit of the time with RACORs (primaries) as once you start to pull significant vacuum dissolved AIR is pulled out of the fuel and that disrupts the clean flow of fuel to the engine pretty quickly. Someone else noted that they've seen a plugged secondary stop the engine at idle; that makes two!

My "general rule" is that filters get changed with the oil, both primary and secondary, and I monitor the primaries with a vacuum gauge. That should keep 'ya out of trouble.

You can put a pressure gauge on the secondary ("Tee" it off the hobbs switch) which would provide an instant check for this sort of condition but this has some hazard associated with it related to leaks (about the same as an oil pressure gauge) since it is under significant pressure (~60psi.)

BTW you might be interested in this article I wrote for BoatDiesel about retrofitting a more modern filter system combined with a priming/polishing pump. Its not terribly expensive and will keep that secondary as a true "last chance" filter as this setup will filter to or beyond where the secondary does. That setup is VASTLY superior to the RACOR setup usually used in terms of fuel quality and the best feature of all is that it goes a LOT further between filter element changes as well.

http://www.denninger.net/filters/out-with-the-old.htm

mobilemn1
05-15-2009, 12:40 PM
Bob, as YB says, that's what it's all about. Hoffers helping fellow hoffers, just pass it on.

Safe journey

bobk
05-15-2009, 12:56 PM
I change primaties and secondaries each time I change oil. Everything was fresh in late March. Wierd how so much got past the Racor. I'm running on a 20 micron Racor now as that is what was on board. Since I cruise slow, it ought to work. So far so good.

Again thanks everyone.

Bob
Chateau de Mer
1981 Series I 48 MY

Genesis
05-15-2009, 03:22 PM
Wow. That is... disturbing.

The "last chance" filter is a nominal 7 micron (if you're using the "stock" element.)

For that to plug on less than 100 hour intervals unless you've had to change SEVERAL RACORs is more than a bit unusual.

Check and make sure your RACOR isn't being bypassed somehow (e.g. element that doesn't seal on the tube, etc)

34Hatt
05-15-2009, 03:25 PM
First did you CHANGE the sec filter? March does not mean much.


Well Guess Ill say it GOOD CALL DAVE!!

mobilemn1
05-15-2009, 03:56 PM
to give a little more history of the problem, the main filter was the one completely or near totally stopped up. Once Bob and I changed that one the engine fired. But Bob knows his boat and the boat would not idle as stable as it had before. We were trying to eliminated one thing at a time before condemning the pump on the blower as the culprit. The engine would idle at between 500 and 650 rpms, and Bob said it had always been stable at 600 on the nose. But what we did eliminated the main fuel pump, and he picked up some new secondary filters and all was ok with the idleing, back to 600rpm.

Bob had refueled the day earlier and I suspect that if the fuel had been delivered fresh to a provider that he thought was safe, there were some floating biologicals in the fuel that caused the problem. Most people never ask when someone had fuel delivered before pumping and fuel even from a reliable source can be affected by a new fuel supply. It takes a while for the gunk to settle back down below the supply pick up.

jim rosenthal
05-15-2009, 04:31 PM
Glad you are back on the "road". And very nice that a HOF member helped you out, that's "right neighborly", as they say down there.

I had Racor filters in the past with Cat engines. I had a number of problems with jammed injectors, etc. I went to much larger Racors but then changed those out for Fleetguard systems I got from Tony Athens. They are rated for a common-rail engine the size of a Cummins M11- about 650 hp. Quite a bit larger than my 370Bs. They seem to work very well indeed.

There is another advantage to using spin-on type filters like these: when you can't get Fleetguard spin-ons, you can cross the ID number over and get NAPAs (which are made by Wix, and very good) or Baldwins (also good), etc. You are not limited to Racor products. There are two separate cans- one is the fuel-water separator unit and the other is the primary fuel filter. And then there is a secondary or "last chance" filter on the engine itself..also a Fleetguard filter.

There is also a good discussion of fuel filtration on Tony's web site at www.sbmar.com, I think it is. Talks a lot about how fuel filters are tested and rated; easily readable and very helpful. The latest version of this system that he sells also incorporates a fuel priming bulb which is a simple and effective way of refilling the system when you've changed the filter cans.

Genesis
05-15-2009, 05:38 PM
Yep - that write-up I linked to is Tony's system.

HIGHLY recommended.

I was NOT a believer until I lived with it for a while.

I became one.

Fast.

MikeP
05-15-2009, 06:16 PM
Ditto to the above - the Athens system is excellent - excellent performance, easier to service, takes less space...what's not to like? I replaced my Racors several years ago.

SKYCHENEY
05-15-2009, 11:07 PM
If you run a 2 micron Racor, then the secondary is just a fail safe to catch something that the fuel pump spits out. You should never actually have to change that secondary as the the Racor should do the job, just monitor the vac gauge.

captddis
05-15-2009, 11:28 PM
If you run a 2 micron Racor, then the secondary is just a fail safe to catch something that the fuel pump spits out. You should never actually have to change that secondary as the the Racor should do the job, just monitor the vac gauge.


Thats right. I will never understand the logic of using a 30 mic primary filter. Have to laugh at hearing that it maximizes filter life. Using a 30 mic primary will cause the secondary to plug BEFORE the Racor. Not to mention letting all the crap run through the lines and pump. I want the racor to stop the crud not the secondary.

As far as the Fleetguard filters, I keep hearing that they last longer. How? Where does the contaminates go? If they plug the racor but not the fleetguard where are the particles going? Magic?

Genesis
05-16-2009, 01:21 AM
The Fleetguard filters have several times the filtering area of the Racor.

The Racor is a simple pleated media (and not very deep on the pleats either.) The Fleetguard is a combination depth+areal filter, and holds a LOT more crap before it gets plugged up.

Its a totally different design for the media; that is what accounts for the additional capacity.

The Athens system is also a 2-stage design with a bulk 30 micron separator in front of the Stratopore system. That setup meets common rail requirements (which require MUCH more stringent filtering than the old-tech Detroits to avoid injector and high-pressure pump damage) where the Racor isn't even in the same league and does NOT meet the requirements of the newer engines standing alone.

The Racor design was good 20 years ago but filtration technology has improved. The newer setup is also smaller and easier to service.

bobk
05-16-2009, 03:35 PM
Is there any down side to using a 2 micron Racor on DD's? Most of us trawler owners did that, but fuel flows were much lower.

Bob

captddis
05-16-2009, 03:58 PM
The flow rate is the same on the 2,10 or30 mic when new. The difference is the coarser filter lets more through and lasts longer, however the crap that passed through goes to the sec filter. I use 10 mic on almost everything and it is a good trade off. If fuel is clean use a 2 mic. Whatever filter you use watch the vacuum gauge, that will tell you when they are getting fouled.

ron6785
05-16-2009, 06:45 PM
Using 2 micons on the primaries is alot of work. Granted if your not running the boat much then using 2's saves you from changing the primary occassionally. 10's or 20's keep most of the junk out of the seconds.
DD's will run fine on just about any filter system if they are run, the problem is that if the boat is not used frequently, or the fuel is really bad. For the most part alot of crap that gets thru the filters like alge gets burned anyway. Generally the problem is air and many times its the filter o-rings or the top on filter is just not tight . KISS is usually rule in terms of diagnosis.

captddis
05-17-2009, 08:04 AM
Guys there is NO 20 micron Racor. They are 2,10 and 30 mic. 2020SM brown =2mic. 2020 TM blue is 10 mic. 2020 PM red is 30 mic. The 30 will plug the secondary before the primary. Your call......

Red Hatt
05-17-2009, 09:45 PM
I have New John Derere engine's well about 2 years old now. I added the double 1000 reaco's 30 m.---- on the engine's there's a 10m. and inside that is a 2m. I thought of changing the 30 to 10 or 20 M. but thought it might strain the fuel pump. What do you guys think should I leave well enough alone? I only put about 100 hours a year or less on the engine's.

SKYCHENEY
05-17-2009, 09:51 PM
I have New John Derere engine's well about 2 years old now. I added the double 1000 reaco's 30 m.---- on the engine's there's a 10m. and inside that is a 2m. I thought of changing the 30 to 10 or 20 M. but thought it might strain the fuel pump. What do you guys think should I leave well enough alone? I only put about 100 hours a year or less on the engine's.

Put 2 micron filters in the Racors and add the vac guages if you don't have them. I run 2 micron filters in my Racors and I run the OEM secondaries at 7 micron(?). I don't put any cartridge at all in the on-engine primaries as they would serve no purpose. In fact, the only reason I run the OEM secondaries is to catch parts of the fuel pump should it decide to self-destruct for some reason.

bobk
05-19-2009, 05:19 PM
I now have 200+ miles on the new starboard filters and 1200 on the port ones which seem fine. Today we ran out of Hampton Roads into 5-6' seas to stirr things up but it was A-OK. We continued for several hours in 3-4 and then 2-223' seas for many hours. Seems strange that just one side had a problem when both draw from the same tank. But I'm not complaining.

Bob