Yanmar 2QM15- Out of Ideas

[stara]

had a fuel tank problem in an old boat. What helped was to take an dinghy outboard fuel tank, fill with diesel and use that instead. That setup worked perfectly. Maybe try that?

[WestcoastCrown]

The saga continues- and I realize I'm not the first one to ever go through this issue. Installed reconditioned exhaust elbow, new exhaust hose, new vent hose for tank, managed to bleed profusely in the process and curse at length. Started up right away and idled like a charm. Took her out and she decided to start pulling the same stuff at the exact same moment as last time. It does not seem to be random as in a piece of gunk getting stuck in the pickup tube. I had even started the timer on my watch it seems to be so regular.

Given that, I believe it is mechanical and beyond my scope of knowledge, and possibly beyond a reasonable amount of blood loss. So I will call the mechanic in the morning & see what they can do. Hopefully will be able to post the "low cost simple solution" found by the mechanic soon.

[charliehows]

if the glitch is time predictable the only thing i can think of that might be functioning on a time scale is the thermostat - i cant think how that might cause the problem you describe but its worth considering. hope the 'low cost simple solution' happens, sounds like you've done the bleeding part which i always think is part of a successful fix..

[DeepFrz]

Whoa, wait, you don't mention running from a fuel line in a different source, such as a 5 gal. fuel container. You also haven't mentioned pulling the fuel pickup tube out of the tank to check it. Two simple things to do before spending money on a mechanic.

[Opie91]

Originally Posted by DeepFrz

Whoa, wait, you don't mention running from a fuel line in a different source, such as a 5 gal. fuel container. You also haven't mentioned pulling the fuel pickup tube out of the tank to check it. Two simple things to do before spending money on a mechanic.

I'll second that!!!!

[s/v 'Faith']

Originally Posted by DeepFrz

Whoa, wait, you don't mention running from a fuel line in a different source, such as a 5 gal. fuel container. You also haven't mentioned pulling the fuel pickup tube out of the tank to check it. Two simple things to do before spending money on a mechanic.

This is the second thing you should have tried, and you would do well to try it before calling in a $$$ "professional"... who may, or may not have any better ideas then you have gotten here so far.

[sailorchic34]

Not sure on the dip tube. Maybe a collapsed hose in the supply. Using a new bit of hose and a 5 gallon jug would tell you if its hose or tank.

If it still does it after using the jug then it might be between the fuel rack and govenor. I'm thinking a loose connection or broken spring or weight could cause the problem.

The things I think about while watching the sun set.. good luck

[WestcoastCrown]

So, took a step back from last week and read through all of the posts in the clear light of day. Connected a jerry can to the engine mounted secondary filter, bypassing the lift pump and.....engine runs like a clock. Is happiest around 2000-2100 rpm, tends to smoke after that but after all it is a 40 year old engine.

The next task is to connect to the lift pump and see if it still runs well. If it does, then the problem is the tank. If not, then pump is suspect.

Thanks to all for ideas and sharing their experiences. Although it was a steep learning curve being my first diesel, it proved to be invaluable as I now have some confidence in case things go sideways.

[Uncle Bob]

Originally Posted by WestcoastCrown

So, took a step back from last week and read through all of the posts in the clear light of day. Connected a jerry can to the engine mounted secondary filter, bypassing the lift pump and.....engine runs like a clock. Is happiest around 2000-2100 rpm, tends to smoke after that but after all it is a 40 year old engine.

The next task is to connect to the lift pump and see if it still runs well. If it does, then the problem is the tank. If not, then pump is suspect.

Thanks to all for ideas and sharing their experiences. Although it was a steep learning curve being my first diesel, it proved to be invaluable as I now have some confidence in case things go sideways.

My guess would be a pickup or line blockage, could it be DIESEL BUG ? Took me many goes to find and sort a similar issue. Found fine black **** had completely filled fuel lines but all is relatively easy to sort.

[Cheechako]

Originally Posted by WestcoastCrown

So, took a step back from last week and read through all of the posts in the clear light of day. Connected a jerry can to the engine mounted secondary filter, bypassing the lift pump and.....engine runs like a clock. Is happiest around 2000-2100 rpm, tends to smoke after that but after all it is a 40 year old engine.

The next task is to connect to the lift pump and see if it still runs well. If it does, then the problem is the tank. If not, then pump is suspect.

Thanks to all for ideas and sharing their experiences. Although it was a steep learning curve being my first diesel, it proved to be invaluable as I now have some confidence in case things go sideways.

This must be awful hard to just pull the pickup tube and look?

[Rocketman]

If you want to address the smoking problem, it could be something very simple like worn out injectors, or dirty injectors. After having my injectors rebuilt my engine with 6000+hours on it, ran like new again with no smoking issues at all. Before having the injectors rebuilt my engine ran fine but smoked at higher RPMS. I also gained power and fuel economy.

[JimJohnston]

Hi West coast crown,

I just read the thread and I would be interested in knowing whether you finally resolved the problem you were encountering and what the solution was. I had a similar problem where the lift pump appeared to be to weak to generate a strong enough head. Installing an electric pump made things a lot better. But I also went through cleaning the exhaust elbow, polishing the fuel, changing filters, etc. With an older boat, all the variables can start showing up...

Jim

[WestcoastCrown]

Status- Decided to take the boat on a "close to home" outing for a few days running off the 12v pump & jerry can. 20 mins off the dock the situation reappears, so a change in plans happens as we head to a small town nearby where the mechanic lives.

He is familiar with the problems and has been providing advice on what do do to resolve the situation. He came to the boat & pulled off return line from the injectors and discovered air bubbles coming out of the return line into the secondary filter which he attributed to faulty injectors. Everything works fine at lower RPM, but at higher RPM under load the bubbles appear.

The new injectors will be installed Tuesday and we will give it a run to test it. I dipped the tank and the fuel is spotless. The filters are also clean on both the primary and secondary with no sign of gunk.

As the clearance from the top of the tank to the bottom of the cockpit sole is about 6" I cannot pull the fuel feed tube without pulling the tank. The previous owner had the tank emptied and cleaned before the sale ( receipts were provided) so I do not believe it is the tank and all supply and vent lines are all new.

When the injectors are installed the new 12V pump will be installed inline on the fuel line. The return line will be Tee-d to empty back to the fuel tank which will also make the unit self-bleeding by using the 12V pump when the filters are changed. The new Yanmars apparently have the return line run to the tank which avoids these problems.

Will provide news on the outcome after the new injectors. Hopefully it will good news.

[David W]

Originally Posted by WestcoastCrown

Status- Decided to take the boat on a "close to home" outing for a few days running off the 12v pump & jerry can. 20 mins off the dock the situation reappears, so a change in plans happens as we head to a small town nearby where the mechanic lives.

He is familiar with the problems and has been providing advice on what do do to resolve the situation. He came to the boat & pulled off return line from the injectors and discovered air bubbles coming out of the return line into the secondary filter which he attributed to faulty injectors. Everything works fine at lower RPM, but at higher RPM under load the bubbles appear.

The new injectors will be installed Tuesday and we will give it a run to test it. I dipped the tank and the fuel is spotless. The filters are also clean on both the primary and secondary with no sign of gunk.

As the clearance from the top of the tank to the bottom of the cockpit sole is about 6" I cannot pull the fuel feed tube without pulling the tank. The previous owner had the tank emptied and cleaned before the sale ( receipts were provided) so I do not believe it is the tank and all supply and vent lines are all new.

When the injectors are installed the new 12V pump will be installed inline on the fuel line. The return line will be Tee-d to empty back to the fuel tank which will also make the unit self-bleeding by using the 12V pump when the filters are changed. The new Yanmars apparently have the return line run to the tank which avoids these problems.

Will provide news on the outcome after the new injectors. Hopefully it will good news.

Good grief, this is a saga! I'm really sorry to hear you are still having such problems. Wonder how you've made out since this post.

[WestcoastCrown]

Glad to report the saga has ended. The mechanic replaced the injectors, replumbed the fuel line etc, etc. Yesterday was the first outing since all of the work was done, as the hydraulic backstay adjuster required rebuilding also. With the newly rebuilt backstay adjuster reinstalled and working, we headed out.

It ran like a clock. It starts much more quickly, has more power and doesn't smoke. It revs much easier and generally sounds smoother. We motored along for over an hour and pushed the revs up to test it, but not even a hiccup.

Seeeing as it was a beautiful sunny day with about 15 knots of breeze we hoisted the sails, confident that we could restart and motor into the dock without problems . One of those great days that reminds you why you own a sailboat.

When we got back to the dock my wife commented " That was a really relaxing day, not like all of the rest the days we have had on it recently".

So thanks to all for your input and ideas, & I hope if anyone is having the same issues this thread helps them out.