Generic diesel problem/question?

[84Jeeper]

I have a Yanmar B27 excavator with a 3 cyl diesel engine. Well, I let it sit for several years and upon startup something is amiss. The throttle is not responding correctly. It will start (after a lot of cranking) and run smooth. But if I push the throttle all the way down to the stop position the motor does not immediately stop like it used to. It slowly idles down and eventually it usually does stop (initially it would not stop at all). When pulling the throttle to max the engine will initially gain a few rpms and then slowly the rpms will continue to increase to what seems like a normal level but when trying to use the hydraulics there is little power and the engine rpm will drop right down.

It seems like everything is just real sluggish to respond to the throttle with no power available. It also seems like the more it runs (maybe 30 mins total) the better it gets (small improvement so far). I suspect something is stuck and working it's way loose? Should I add some sort of injector cleaner to the fuel? I have no idea about diesel engines...

The mechanical linkage is fine.

I assume this behavior is not related to this particular model but a result of letting a diesel engine sit too long and something getting gummed up?

Please advise...

Thanks!

If it matters this is what the throttle linkage goes to....

 

[LouNY]

I would say to change the fuel filter and add some #1 fuel oil to it, run it without working it, just varying the throttle untill she responds better.
Have you put fresh fuel in it or is it old fuel also.

 

[Roadworthy]

On many diesels there is rack inside the side plate of the fuel pump. It or the linkage leading to it can get sticky or hung. Lube the linkage and check a parts breakdown to see if you have such a rack.

 

[rScotty]

I would say to change the fuel filter and add some #1 fuel oil to it, run it without working it, just varying the throttle untill she responds better.
Have you put fresh fuel in it or is it old fuel also.

Yep, like Lou says it sounds like the old fuel got contaminated. Water or bacteria will do that & probably has. You probably have crud throughout that fuel system. But even if that isn't the problem, you still have to get clean new diesel running through that system for awhile before you can go any farther with the diagnosis.

BTW, the reason Lou says to use #1 fuel is that #1 is a slightly lighter diesel fuel with better ability to dissolve crud.
Most automotive diesel from the pump is #1 or even slightly better. So get some new fuel, put some cleaner/additive in with it. And clean EVERYTHING. That probably means draining the tank and the changing the filters too. Sometimes it takes several filter changes.
luck,
rScotty

 

[84Jeeper]

It is the old fuel

Sounds like great advice. I will have to figure out where to get a filter for it but at least it's easy to get to!

...and thanks for the clarification about #1 diesel...my next question was going to be where do I get that? LOL

 

[CoyPatton]

Buy several filters and plan to change them out frequently.
The old fuel is now only useful for starting fires in my opinion.
Add a fuel cleaner/lube to your clean fresh diesel. Best if it is one that protects against algae.
If you can remove the fuel tank, it will make cleaning somewhat easier.
For future reference, any time a diesel has set for an extended period (not a couple of months but a year or longer) try not to use the old fuel. Condensation causes water in the fuel and water leads to algae.

 

[California]

That filter housing in the picture looks like the universal one on our Yanmar tractors. The only alternatives are a long or short filter element and a replacement long filter bowl isn't expensive if you can't find the short filter.

Your local Tractor Supply, Autozone, or most likely NAPA will have the Yanmar filter element and its not expensive. If you are in the boondocks then Hoyetractor.com mailorder is the best source, they have everything.

I agree, you need fresh fuel to do the flushing.

I'm cheap, I would drain the existing fuel downstream from the existing filter, on the chance that it isn't the problem and might be re-used later, and so you can avoid the nuisance of getting rid of it. Then use a fresh filter element for the fresh fuel during the system flush project, then finally a second one when you put the machine back in service, and just check the second one after a while. Replace only if needed.


These new components are the common ones. I bought this filter assembly from a VN 'rebuilt' dealer and nobody had a replacement for this third style of ultra-short element.

 

[PILOON]

"nobody had a replacement for this third style of ultra-short element."

I ran into same problem on my Mitsubishi.
Longer bowl would hit the flywheel bell housing and short one not to be found.
Problem was my bowl had shrunk and filters would not fit.
I modified by fitting a drain cock and simply dedicated it to be a water separator.
I drain the bowl from time to time via the drain cock thus ridding of water and accumulated crud that may be present.

Next I cut the fuel line past the bowl and inserted a paper type in line fuel filter which I simply replace annually.
6 years or so now and no problems.
The inline paper element takes care of any minor debris that gets by my 'separator' bowl.

 

[LouNY]

#1 fuel oil is commonly called kerosene.

 

[84Jeeper]

Update #1

Well I pulled the filter apart and it fell apart. See the pic. The donut looking stuff between the spring and the filter is gunk from the bottom of the bowl. The filter was a nice reuseable metal filter...before the bottom rotted off, as can be seen sitting to the right of the filter. You can of course see all the trash on the outside of the filter and what was on the inside of the bottom of the filter.

Drained the diesel....smelled like paint thinner.

Then noticed it had a second filter. I opened that and drained the fuel from it. I don't think it was doing much as it had a piece of screen that was larger than the first filter?

Primed everything up with new fuel and "magic" additives which are supposed to clean injectors etc...

After much cranking it almost wanted to run but not quite. It had been getting progressively harder to start during the day yesterday (and the engine was warm) even though it seemed to be running better once started.

So the battery gave up and I brought it in to charge. I'll wait till it gets warm tomorrow and give it another shot.

I'm hopeful that the fresh fuel and magic additives will hopefully soften up something overnight and it will run....that could be misplaced hope...

ps Autozone had no filter so I just added an inline one as suggested.