Groundhog Day

[djousset]

After working through (and thinking I solved) fuel/air-in-line issues it feels like I am back to square one. Background: Definitely had air in the system, troubleshoot, bled fully, cleared air, test runs, engine up and sounding good, followed by 2+ weeks of no problems with a decent amount of motoring. And then BAM, the engine quit at the worst possible place and time. Thanks to an assist by a nearby power boat all ended well. I see no signs of a leak anywhere, and there’s no air from the fuel tank, to the lift pump, to the secondary filter, but I did discover diesel fuel in the pan under the engine, which I've not seen before. I assume this means there IS a leak. And in a place I am not qualified to touch. So. Very. Frustrating.
Professional help is a week or more away. Thoughts?

[Stu Jackson]

Originally Posted by djousset

>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>
And in a place I am not qualified to touch.

>>>>>>>>>>>>>>>>>

Sorry to hear. It happens to all of us.


Could you please explain what ^^^^ means?

[skipmac]

Had the same, almost impossible to diagnose problem with my Pearson 42. After trying this and that and even the other I finally figured our the only way to zero in on the problem was to start at one end and work through the system.

It might help to check the primary and secondary filters to see if either has air in it. That could point you at which end to start. But what finally found my problem.

Get a completely clean plastic jug a fill with fresh diesel and a few feet of appropriate sized fuel hose. Stick one end of the hose in the jug and connect the other to the input of the primary filter (the first one in line coming from the fuel tank). Run the engine and see if it quits or keeps going. If it keeps going then the problem is between the primary and the fuel tank. If it quits, move the hose to the next connection in line after the primary filter, repeat the test. Same answer. If the engine keeps going then the problem is behind you. If it quits again move to the next connection in line.

Once you get to a spot where the engine runs then you know the problem is the step just before.

[skipmac]

This sounds like it might be a new and different problem from your original but the same technique to isolate the problem is still applicable.

But, if you found a noticeable amount of fuel under the engine you should be able to spot the leak. Wipe down everything, crank the engine if you can, and examine everything with a bright light.

[Deep Blue Water]

Diane,
do you have access to a handheld vacuum pump? The one below is a brake bleeder but can be used for many other applications.

https://www.amazon.com/Mityvac-MV851...181538&sr=8-16

Using skipmac's advice start at one end and test each section, even if it's a steel line as there may be a crack. You should be able to pump and observe a solid vacuum as you go along, if it changes then you have an issue.

[grantmc]

I recently shared the same fault characteristics. A frustrating fuel leak/air intake, beyond measure.

Ultimately I was able to determine that the escaping fuel was in the vicinity of the water/diesel filter (clue a very very small wetness of diesel in the engine bay below). But there seemed nothing wrong with the filter, nor any of the pipes leading to and from. Eventually I did engage an engineer who in 3 minutes confirmed that it was the filter housing at fault. The cause was that in changing the filter within I had over tightened, causing the plastic base to have the most minute crack, thus leaking. A common mistake for the DIY boat mechanic.

The filter in question is a Ryco as pictured. Although most filters follow the same pattern, and the bases are plastic (not glass as I had always thought) with a small washer for the drain plug. And it was at that spot where it had cracked.

[Stu Jackson]

This applies only to the Racor 24 Series housings:


Fuel Starvation and The Obscure Check Ball Valve
https://c34.org/bbs/index.php/topic,10681.0.html
and
https://forums.sailboatowners.com/th...l%20Starvation

[djousset]

@stujackson. Having been down this road recently (see other thread I started re:fuel) I feel pretty confident that the leak is on the high pressure side of things and although I like to dig in this feels out of my league.

@skipmac. I can't even get the engine to start.

I did clean the pan and then cranked the engine watching carefully for drips, could find nothing but to be fair I was not in the best mood for troubleshooting....

[deblen]

Originally Posted by djousset

@stujackson. Having been down this road recently (see other thread I started re:fuel) I feel pretty confident that the leak is on the high pressure side of things and although I like to dig in this feels out of my league.

@skipmac. I can't even get the engine to start.

I did clean the pan and then cranked the engine watching carefully for drips, could find nothing but to be fair I was not in the best mood for troubleshooting....

Best to close your engine cooling seacock to prevent waterlock due to excessive cranking.
Check your fuel tank vent for blockage.(remove filler cap temporarily)
Install an inline squeeze bulb (outboard motor type) primer bulb before primary filter,in order to pressurize system. My bulb is still good after 12yrs for those that believe they rot
What breed of engine?
Cheers/Len


https://ca.binnacle.com/p6446/Scepte...duct_info.html

[djousset]

Originally Posted by deblen

Best to close your engine cooling seacock to prevent waterlock due to excessive cranking.
Check your fuel tank vent for blockage.(remove filler cap temporarily)
Install an inline squeeze bulb (outboard motor type) primer bulb before primary filter,in order to pressurize system. My bulb is still good after 12yrs for those that believe they rot
What breed of engine?
Cheers/Len


https://ca.binnacle.com/p6446/Scepte...duct_info.html

Len, it's a yanmar 2gm20f. I had done all of the above, and more, and was up and running fine for two weeks. No excessive cranking, just a few tries to see if there was anything obvious.

[deblen]

Originally Posted by djousset

After working through (and thinking I solved) fuel/air-in-line issues it feels like I am back to square one. Background: Definitely had air in the system, troubleshoot, bled fully, cleared air, test runs, engine up and sounding good, followed by 2+ weeks of no problems with a decent amount of motoring. And then BAM, the engine quit at the worst possible place and time. Thanks to an assist by a nearby power boat all ended well. I see no signs of a leak anywhere, and there’s no air from the fuel tank, to the lift pump, to the secondary filter, but I did discover diesel fuel in the pan under the engine, which I've not seen before. I assume this means there IS a leak. And in a place I am not qualified to touch. So. Very. Frustrating.
Professional help is a week or more away. Thoughts?

Looks like you have eliminated everything up to the lift pump inlet.
Start looking at lift pump outlet & beyond. As you state,you are now getting into "mechanic territory". Since it sounds as if you are stranded away from a mechanic,only you can decide if you want to go further.
Here is a link to the parts manual. I suggest you keep looking for fuel under pressure from the outlet of the lift pump thru the injection pump & to inj.nozzles. Do you have return fuel out of the nozzle return line?


http://j30.us/files/Yanmar-2GM20-Parts-List.pdf

[deblen]

This service manual may help if you decide to proceed.
Suggest you take pics & make notes as you go./ L


http://j30.us/files/YanmarGM&HMWorkshopManual.pdf

[skipmac]

Originally Posted by djousset

@stujackson. Having been down this road recently (see other thread I started re:fuel) I feel pretty confident that the leak is on the high pressure side of things and although I like to dig in this feels out of my league.

@skipmac. I can't even get the engine to start.

I did clean the pan and then cranked the engine watching carefully for drips, could find nothing but to be fair I was not in the best mood for troubleshooting....

Been there, done that and feel your frustration. If the engine currently won't start at all as a first step I would first loosen a fuel line at an injector, pump the manual pump on the engine and see if you have fuel at the injector.

[Compass790]

Wrap every joint on your fuel lines in toilet paper or a paper towel if toilet paper offends yr sensibilitys. then you should be able to spot leak. Or you can dust with talcum powder. Wipe all joints dry first. Just try pressurising with squeeze bulb 1st before any cranking. If your fuel lines are +30 years old they could be well knackered.

Almost certainly you are getting air in the system again.
You aint having much luck!


High pressure line leaks are usually pretty obvious. Dont forgot get to turn raw water intake off if cranking motor for long periods decompressed or not starting as others mention.

[djousset]

Originally Posted by Compass790

Wrap every joint on your fuel lines in toilet paper or a paper towel if toilet paper offends yr sensibilitys. then you should be able to spot leak. Or you can dust with talcum powder. Wipe all joints dry first. Just try pressurising with squeeze bulb 1st before any cranking. If your fuel lines are +30 years old they could be well knackered.

Almost certainly you are getting air in the system again.
You aint having much luck!


High pressure line leaks are usually pretty obvious. Dont forgot get to turn raw water intake off if cranking motor for long periods decompressed or not starting as others mention.

Thx all fpr the advice, I am going to move aboard and dig in and try to isolate the problem starting with the tank and moving through the system. Lines are all newer, as are clamps, and filters, decent fuel etc. Stay tuned.