Fuel starvation symptoms

Understood on the clamps but they are making good connection. Issue is for sure between the bulb I put in and the tank. I was able to get a look top of thank where the gate valve is but there’s no hatch. That valve looks suspect so my plan is to try and tighten it.

I’m temporarily removing all of the hose and replacing with clear hose from the tank line to the racor. Bypass the valve up top and see if air gets in. The hose and gate valves are all suspect. I’d like to find the issue rather then start replacing everything.

Thanks for the info on the thread sealer ext. if I need to I’ll redo all of it for sure. The hose is not very flexible not sure if that’s normal for the type used. It’s real thick 5/16 ID.

I have to be truthful here at the expense of losing friends on TF. Raccor are way overpriced and overrated try as I might I can't justify them, they simply don't add up.
As to your problem of fuel starvation have you got a non return valve at the fuel tank ?
If it runs for a while and stops you have air ingress, go back down the line segment by segment until you find full flow, then your problem starts there.
I'll tell you a little story.
I fitted a Caterpillar water separator filter and had a similar problem. As long as I kept the revs on the engine it worked fine, when it was on tick-over it stopped within 5 minutes.
The problem ?
When I fitted the Caterpillar filter I overtightened one of the olives on the fuel line. My fault entirely, I cut the end off the overtightened distorted pipe, made a new connection and it still works perfectly 15 years later.
Its called experience.
Take it step by step, once you've found and fixed it and you'll be all bright eyed and bushy tailed again.
Happy Cruising.

I had the same problem on my Lehman 80... it would run for about an hour and a half or so then die. I could bleed it and get another hour and a half out of it. The problem was always that the secondary filter nearest the injector pump ended up empty. I looked everywhere for an air leak, even took apart the fuel tank selector valves and rebuilt them to no avail. I finally installed a cheap in-line 12v electric fuel pump just after the fuel tank selector valves but before the Racor primary filter. As long as I ran the electric fuel pump the engine would run for 24 hrs or more. It still bugged me that I had a leak somewhere even though I couldn't find it. So, I tore strips of paper towels and wrapped every single fuel connection between the electric pump and the in-line secondary filters. I turned the electric fuel pump on and let it run overnight (engine not running). The next morning I checked the paper towel strips and found one of them with just a slight amount of fuel on it - not saturated, just like a few drops. I took that connection apart, cleaned it up and re-connected. That fixed the problem. So, no, it won't hurt anything to leave a pump connected to your fuel system and leave it pressurized overnight. But, you've got to have some sort of leak detection system since the leak could be very small!

As a side benefit, the electric pump also allowed me to easily fill the Racor after changing the filter element and to easily bleed the engine without using the on-engine manual fuel pump.

Thanks for that info. I was worried I might fill crank case with diesle with the pressure. I guess the ingector pump blocks it when motors not running.

Tomorrow afternoon I’m going to use a Schrader valve connected to a psi gauge. Going to shut the valve at the tank and put few psi of air between where I have the bulb and the tank. Use soap outside to look for bubbles.

I know it’s not anti siphon, vent or clogg. It’s air. I’m getting tiny foamy diesle coming out of the squeeze bulb.

I think I’ll find it tomorrow cross fingers I’ll be posting back the problem location. Otherwise I’m redoing everything to the racor.

Your injection pump is like a small engine, with pistons, valves, etc. It's job is to push the fuel hard enough that it will pop the injectors to atomize the fuel in the cylinders. No way you're ever going to create enough pressure to push past the injector pump.

Good luck! Use more than a "few psi", really pump it up, you're not going to hurt anything. And, use very dilute soapy water - it bubbles much easier under low pressure than less dilute soap.

Irish Rambler said:

I have to be truthful here at the expense of losing friends on TF. Raccor are way overpriced and overrated try as I might I can't justify them, they simply don't add Up.

Click to expand...

I agree heartily, visit sbmar.com for the real thing.

Ok so I pressure tested the whole system and I think I know where the leak is up in the gate valve manifold. Issue is I believe the gate valve is only leaking under vacuum. I pumped 15 psi into the line and found no leaks and it held steady for 20 min.. I still get air into the bulb even when the port side gate valve is shut with the center one open to the other tank. That limits my issue to the T and gate valve on the port side!! Have one more test to do to verify, but I'm planning to redo all of it for both sides now. Final test is to run from tank to racor bypassing the gate all together. No issue = leak found! That will happen this weekend.

I want to incorporate a single walbro fuel pump that I can use to prime, polish, or use in case of lift pump failure on either motor/tank.
I came up with what I think will work well for me, but looking for input from you all because its obvious you have loads of combined experience.

Plan is to use lever valves for the pump flow direction on the out side of both filters and Tees back to the gate valve out. A Tee with a valve in 4 places. Using those in one open valve configuration or another, I should be able to pump to either motor, polish fuel from either tank to tank, or bleed to either motor. Looking for validation on my not so artistic diagram attached..

My biggest concern as of now is if I'm using the Walbro pump in this way as a backup to a failed lift pump scenario, it will be competing with the lift pump on the working side. Will the competing pumps going in opposite directions of the racor out flow cause a problem? My gut says yes.. The situation will probably never be used as I can always get back on one motor, BUT Id like to know if there's a better way (with one pump) to do what I'm trying to do.

Here's the fuel schematic on MOJO. A single engine but 4 fuel tanks. The tank manifold isn't shown, only the valving for the filter system. With this setup I can filter with the Gulf Coast paper towel filter, the Racor 500 filter, both filters in series or neither filter. If one filter shows symptoms of clogging I can switch to the other filter underway, change the offending filter and switch back. We typically run while continuously filtering with the Gulf Coast filter and keep the Racor 500 as a backup. Never needed it, but it's there just in case! Fuel can be either sent to the engine or recirculated back to any tank. It's worked perfectly for the past 16 years or so. 3-way valves greatly simplify the plumbing and reduce cost.

Schematic:


Picture of the valving:

Please understand first and foremost I've no wish to offend anyone by my straight talking which some may find a little too direct.
What in heavens name do you need all those overpriced Raccor filters for ?
Why are simple straight forward fuel systems turned into a plumbers nightmare ?
Your engine is supplied with a pre-filter and fuel filter with a fine gauze in the lift pump and should be serviced regularly.
If the engineers who designed the engine feel its sufficient why all the mental masturbation ?
EACH tank requires a non return valve at the tank, if you have more than one tank a simple lever valve (handle inline ON, at 90 degrees OFF) system will suffice .
ALL tanks need a sump and drain cock that can be checked once a month to drain any sediment or moisture, alternatively, drain the tank of fuel, use a wet & dry vacuum cleaner to hoover the floor of the tank and refill it.
K.I.S.S.

"If the engineers who designed the engine feel its sufficient why all the mental masturbation ?"

Many installed engines were built for farm service , lawn service or small trucks.

The fuel turnover is far quicker with a 30G tank than a 300G tank.

Most of the fuel hassles come from poor tanks that get water in the fuel , so multiple filters (any brand) is a help.

My favorite is the old style glass jar with a woven "sock" built to condense the water on the sock surface and then have it drip to the jar bottom.

These show the water , and with a gravity system can be cleared in seconds.

Sometimes the old stuff is more useful than the new expensive stuff.

Here is the style , although its fitted with a replaceable filter , rather than the cruisers delight , a re useable filter.

https://utahbiodieselsupply.com/fuelfilters.php#goldenrodfilter

Pretty sure most engine manufactures recommend off engine primary filtering.

KISS is not a singular possibility if you want different functions for a fuel system. Polishing, redundant filter switching, auxiliary feeds, etc can all require "extra" ....but not necessarily complicated plumbing.

Irish Rambler said:

Your engine is supplied with a pre-filter and fuel filter with a fine gauze in the lift pump and should be serviced regularly.
If the engineers who designed the engine feel its sufficient why all the mental masturbation ?
EACH tank requires a non return valve at the tank, if you have more than one tank a simple lever valve (handle inline ON, at 90 degrees OFF) system will suffice .
ALL tanks need a sump and drain cock that can be checked once a month to drain any sediment or moisture, alternatively, drain the tank of fuel, use a wet & dry vacuum cleaner to hoover the floor of the tank and refill it.
K.I.S.S.

Click to expand...

In my case, my tanks do not have a sump or drain and interior access is limited. It would be nice if they did, but even so, I'd still have an off-engine fuel filtering system!

I'd argue that the engine design engineers intended all along that the engine be run with a separate fuel filtration system. The small on-engine filter is designed as a fail-safe system to protect the injection pump. It was never intended to used as the sole means of fuel filtration. Most over-the-road trucks incorporate a separate off-engine fuel filter because it is easier to maintain and doesn't require bleeding the engine after changing.

"Why are simple straight forward fuel systems turned into a plumbers nightmare."? The answer is to prevent even worse nightmares at sea. Servicing a clogged on-engine fuel filter at sea is a nightmare that requires shutting down the engine, risking severe burns to change the filter and bleeding the engine before re-start. Not something you want to do while rolling 20-30 degrees mid-ocean in a hot engine room! With a duel off-engine filter system, if during routine engine checks you see an increase in vacuum indicating a fuel restriction from a fouled filter you can turn a valve to switch to the alternate filter while underway, change the fouled filter and switch back without ever shutting down the engine. On MOJO we run on the Gulf Coast filter - the Racor is just a back-up. A filter change costs the price of a roll of Bounty paper towels and filters to sub-micron levels. The on-engine filter remains clean and does not need changing. A well designed off-engine filtering system is not mental masturbation. It's a practical approach to prevent problems, and to also easily solve those that might happen.

In a perfect world where only crystal clean fuel is dispensed at the pump, tanks are drained and cleaned regularly, and the on-engine filter is serviced monthly, you're probably OK relying on that filter alone. But in a world where there's a very real risk of taking on a load of dirty fuel, where fuel can sit in tanks for months or years, and where tanks can't be drained and cleaned frequently, without some form of pre-filtering even a brand new small on-engine filter can/will quickly become restricted, leaving you in extremis!

I'd be surprised if 90+% of all trawlers and sailboats don't have some sort of off-engine fuel filter in addition to the primary on-engine filter(s). Boats that rely on just their engine for propulsion, especially those designed to cross oceans, will have a dual filtration system allowing them to keep running while filters are serviced.

I already have the racors, and they are doing their job, so why would I ditch them? Looking at my setup now its simple. The pump will add some complexity but not that much. My biggest concern is the pump making the bleeding more of a mess then with a bulb. Ill probably just replace the gate valves and think on it some more..

I don't think you'll find bleeding the engine any messier with an electric pump than with a squeeze bulb. You're just cracking the fitting to allow air to escape, and as soon as you get good fuel you tighten the fitting. The pump will run against a closed system but it's not going to put out enough pressure to cause fuel to spray when a fitting is cracked. I do recommend mounting a switch near the engine so you can turn the pump on and off when you're in the engine space. I have a fuel pump switch at the helm because we typically run it when underway although it's not necessary to do so. I just run it to make sure that if I do ever develop an tiny air leak, it will ooze fuel rather than suck air and kill my engine at the wrong time. I'd rather have to clean up a little fuel than bleed a hot engine at sea or have the engine die when I'm entering an inlet or maneuvering in tight quarters! I also have a switch in the engine room for convenience when filling my fuel filters.

I figured you all might like to know what the issue ended up being. After replacing sections of hose and finally bypassing the gate valve manifold with new hose the issue remained untell tonight.

I recieved the pipe thread stuff recommended. Knowing the leak was somewhere in the Copper between the aft end where it connects to the hose and the pickup gate valve at the tank, I started taking the flair fittings apart to clean and reseal. Well once I got the flair to barb fitting off I was cleaning the female end on the copper tube and the whole tube spun in my hand. Bingo it’s the only place I could not check for bubbles while pressure testing! I was able to contort through the drawer opening and down the little hole in there tovthe top of the tank. Somehow got an end wrench on the flair but and tightend it. No more air bubbles in the squeeze bulb!

As of now that was the last of two leaks I had. The gate valve was also leaking and tightening it resolved that as well.

Next to you all, the most helpful thing in this process was the squeeze bulb. Being able to feel and hear the air helped save a lot of time. Also being able to flip it around and force fuel out of the hose back into the tank countless times saved a lot of mess.

Thanks!

I’ve got twin Lehman 80’s and am having same issues...runs for a short time then stalls with no fuel in the second in-line element on the engine mount filter. I have cleaned the fuel and changed lift pumps and all filters...will try some of the excellent suggestions here. There is guide a manifold system similar to those shown here. Mine has return line valve choices also.when primed they both start and run great.

Mojo just to correct the meaning of my previous post to avoid confusion.
I mean by manufacturers engine filtration standards to be the micron size of the engine mounted fuel filter.
Every boat should have a pre-filter/water separator ( I use a Caterpillar) but again its not necessary to polish the fuel to a higher micron size.
I worked in R&D at Rolls Royce diesels and this was a constant question as MBT's in action certainly don't need to break down.
The fuel tank cleanliness is highly desirable, if you don't have an access hatch or sump drain (and most boats don't) then as I stated use a wet/dry vacuum cleaner to clean the tank as much as practically possible through the level gauge sender fitting.
If you need to rinse the tank, use paraffin and rock the boat to agitate any loose particles before vacuuming any dirty paraffin out.
I used to clean mine once every 2 years of any sediment until I fitted a new tank with both cleaning hatch and sump drain.
Simply draining a cupful of diesel from a sump drain tap every month to ensure its clean will remove any water and prevent microscopic build up at the interface of diesel/water(diesel bug). Diesel is like fine wine, it has microscopic particles when fresh which are in suspension, called 'fines'. When the diesel is allowed to settle these 'fines' will sink to the bottom of the tank to form sediment.
No amount of re-circulating pumps and filters will lift this sediment off the bed of the tank.
The only way to get these fines back into suspension for re-circulating pumps to be effective is to agitate the whole of the tank floor with a compressed air.
Its easier in fact to retro fit either a cleaning hatch/drain valve either on the side or on top of a tank depending on access.

Tangler said:

I’ve got twin Lehman 80’s and am having same issues...runs for a short time then stalls with no fuel in the second in-line element on the engine mount filter. I have cleaned the fuel and changed lift pumps and all filters...will try some of the excellent suggestions here. There is guide a manifold system similar to those shown here. Mine has return line valve choices also.when primed they both start and run great.

Click to expand...

Sounds like the same situation I had. Such a pain when it takes hrs of running to rear it’s head. I’d suggest checking all flair fittings, hoses ext. if no go I’d jump straight to using a squeez bulb as a test tool unless you have all copper.

Like I said I ripped it all apart in the end to finally find it. I don’t think the issue would be with return line. It’s someplace between that second cav filter (before the injector pump) and the pickup tube in the tank. On mine the racor would first develop a lot of head space in the top before it made its way to the cav filters.

A section of clear tubing temporarily between the pickup and filter will let you know if your loosing prime back into the tank.

It’s been a while since my comment in Nov but I have only been to my boat a few times this winter...it’s some distance from my home. My fuel seems to be choking at the racors but the problem could be before the racors too. I have electric pumps between the fuel manifold and the racors as someone previously described and there is a gauge on the racors...just noticed that the gauge only registers any pressure if the electric pump is turned on..otherwise I suspect the engines use the available fuel from the racors to the engine and then die. With the electric on I can maintain fuel flow. Talked to Racor tech who says as long as the racors are full then they are working...no fuel drains out of the racors back to the tanks. I have no access to the tanks but feed from there does not seem to be a problem. Prior to this problem I did not have to keep the electric running. There should be pressure showing at the gauge without the electric on but I don’t know how much...suggestions ?

Sorry pics are upside down...???

The racor gauge will only show a vacuum if the motors are running for a while. Sounds like you either have a blocked/restricted vent or pickup tube. You might try forcing some air back down into the tank from the line connecting the tank to the racor see if you hear lots of bubbles.. Also if that's good you can open the fuel cap and see if issues go away if they do its probably the vent tube. Basic things Is try.. Good luck!

It looks like the the Reverso manifold, as configured in the pics, requires fuel to be drawn via the electric fuel pump. Where does the “Feed” valve (which is closed) draw from?

What happens when you close the “Fuel” valve (which should probably be labeled “Fuel Pump”) and open the “Feed” valve on the Reverso fuel manifold?

" I cut the line. I used the bulb in revers to blow back into the tank quit a bit to check flow."

My guess is you have a chunk of crud loose wandering about in the fuel tank.

Eventually it gets sucked against the fuel pipe and blocks it.Relieving the suction drops it.

Cure ? Not easy unless the tank has an inspection port.

I would first attempt to remove the fuel pickup pipe and cut the end at a 45deg angle .

A strainer on the end might help but most may not fit down the pickup pipe fitting.

Perhaps this is a case where a dockside fuel filter service might be able to grab the gunk with a good sized suction hose.

The electric should not be required under normal conditions. The reverse manifold levers are set ,by me, to draw from and return to the tank of my choice and is used to help ballast or balance the boat . The return line levers can’t be seen in the pic ...they are behind the generator...the system is proven to work...has been in there well over 10 years that I have had the boat. Taking it out tomorrow and will try the open tank clue.

Well at Least they kept running long enuf to complete the trip. More than 6 hours...longest run for quite a while...still no apparent problem but I did run the electric and I did open the fuel caps enuf to breathe. So I will try next to blow out the lines and/or get the tanks cleaned. Great trip across Vancouver harbour complete with dolphins...fantastic

Well...new problem..kind of...the extra pressure provided by the electric pump seems to have contributed to a leak at the bleed screw of the forward or second engine mount filler. I am finding it difficult to get the copper crush washers found under those bleeder bolts and over tightening that bolt only rips out the threads on the filter mount...had to replace one. So...a source for those copper washers if you know one or are there rubber or whatever washers that replace those copper ones? Also a comment about racors which I find are working as required...the racor tech I talked to suggested the opposite of what I have read here ( ie: eliminating them) .Altho he just may be a little biased he suggested bypassing the engine mount filters and putting 10 micron elements in the racors and using them as the only filters. I’m getting to the point where I may try that unless anyone here sees that as a problem...

Order the copper crush washers from American Diesel or elsewhere - you need spares on board anyway! Meanwhile, your existing washer can be "rejuvenated" by heating with a torch until almost cherry red then quenching in water. This causes them to "puff up" like new ones. They can then be re-used and will seal.

That sounds goodMojo...today I found some at Peterbuilt trucks dealer that have an inner neoprene...I’m guessing ...ring.more flexible and diesel rated. Thought it was worth a try

The primary filter use in large 18 wheel trucks is great.

The fuel is observed thru a plastic housing , there is air on top, and the higher the fuel climbs the more plugged the filter is.

Usually the level is simply monitored till the change is made. The filter housing does not have to be bled after a change , I have no idea how that is achieved .

The plastic bowl might not be rated to not burn for a long enough time to have approval as a boat unit.

The simplest way to be safe is to remote the filter bank OUT of the engine hot space.

The lucky few with high mounted gravity feed tanks have the simplest system to maintain.