J/30 Class Association

Engine Trouble

Posted By: JBiermann

Engine Trouble - 06/14/14 08:15 PM

Hey all,

Motoring in this afternoon at about 1900 rpms and my Yanmar 2QM suddenly slows and dies. Bummer. Tried to restart it, no luck. Motor wasn't overheating and raw water cooling was working fine. I actuated the manual lift and confirmed that there was diesel flowing. Here are a couple clues, I generally get it to fire by poping it into neutral mode and giving it some throttle as I'm cranking. Now, when I'm trying to start it in neutral by giving it some throttle, it just cranks normally and won't catch. I'm thinking blockage at the injector? Any Ideas would be most appreciated, supposed to leave on a little cruise tomorrow!

Thanks,

Josh
Posted By: Cap'n Vic

Re: Engine Trouble - 06/15/14 12:46 AM

just a slow steady die? both injectors go at same time?
perhaps not injectors.

your starting procedure is standard.



Posted By: JBiermann

Re: Engine Trouble - 06/15/14 03:20 AM

It happened fairly quickly, engine running smooth at 1900, making about 5.5 kts. Then I think I heard a subtle change in the engine tone, it seemed slightly more tinny. 30 seconds later, engine revs dropped, engine died and thats where I am now.

Now I'm thinking that maybe my exhaust elbow is blocked up and by running the engine a little higher than normal maybe it backed up and killed the engine? If this happened, that do I need to do to get the engine running again (once I replace the part?)
Posted By: Chris623

Re: Engine Trouble - 06/15/14 03:33 PM

I'd suggest checking for sources of air entering the fuel system - loose fittings and such, then bleeding through to the injectors while watching for bubbles. Also checking that the tank vent plumbing is clear would be a good idea.

GL,

-Chris
Posted By: JBiermann

Re: Engine Trouble - 06/15/14 04:16 PM

Update. I think you were right on Chris. I was following the fuel, clear up to the low pressure pump but very aerated and white from the outlet of the high pressure pump. (see picture) The hose that connects low pressure and high pressure pump shows signs of cracking and wear, unfortunately I have to wait for the Yanmar parts department to open tomorrow before I can get a new one and keep testing. Could this be the culprit or am I chasing a red herring?

[Linked Image]

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Posted By: Rhapsody #348

Re: Engine Trouble - 06/15/14 06:49 PM

You could have diesel bug too - algae that grows in the fuel and plugs the filters. Solution is to pump the tank dry, change the filters and bleed the system.
Posted By: JBiermann

Re: Engine Trouble - 06/15/14 07:10 PM

would the diesel bug clog the injectors? I'm still getting fuel past the racor and fuel filter into the low pressure pump and into the high pressure pump (where it seems to be being aerated), if filter were clogged would I still be moving diesel?
Posted By: Rhapsody #348

Re: Engine Trouble - 06/15/14 07:26 PM

It is possible at a reduced rate - hence the engine is starved for fuel. Pour the fuel into a glass and see if it looks milky. Any sign of particulates or fine bubbles is an indication of contamination. Condensed water from moisture can do the same thing to plug the filters.
Posted By: JBiermann

Re: Engine Trouble - 06/15/14 07:42 PM

ok, well once i repair the low pressure to high pressure line, drain and replace filters, will I need to pull the injectors to get them "unstuck"? or should the engine start at that point and burn out and injector blockage? Thanks for your help guys.
Posted By: JBiermann

Re: Engine Trouble - 06/16/14 04:05 PM

Update: some questions answered and some new. Well it's not air that's mixing with the diesel, it's water. Diesel cap was cross threaded and when it dumped rain for a few days, water must have gotten into the tank. Draining lines, replacing racor, fuel filter et all. Found something very strange when I opened tank to drain and clean out, the diesel/water in there is almost black! Obviously oil must have entered via fuel return line, what might account for this? Draining, wiping clean and dry and starting with fresh diesel. Will change oil too just to be thorough.
Posted By: Jangles13

Re: Engine Trouble - 06/16/14 04:11 PM

It could be bio-growth causing the black. Are you sure it's not dark green? I have experienced diesel getting contaminated in that manner and it's a nightmare to get rid of. It's some sort of algae. The sulfur used to keep it in check I've been told (true?) and now that we're low/zero-sulfur it's easier for the stuff to grow.
Posted By: Jangles13

Re: Engine Trouble - 06/16/14 04:14 PM

This link is directed at large trucks, but the info is similar. Multiple reasons for dark fuel:

http://www.diesel-fuels.com/bad-diesel-fuel.php

Who knew?
Posted By: JBiermann

Re: Engine Trouble - 06/16/14 09:41 PM

Yeah, that makes some good sense, the dark color must be the bug. So I'm thinking I'll drain the tank completely, wipe it all down with bleach or something once it's empty then dry it out thoroughly? Would something simple like a bleach wipe down be an effective biocide?
Posted By: Rhapsody #348

Re: Engine Trouble - 06/17/14 02:07 AM

Use Kerosene to wipe it down. It will help break up the sludge.
Posted By: JBiermann

Re: Engine Trouble - 06/18/14 02:31 AM

Thanks bill, used kerosene to clean out the tank as best I could, definitely some sludge in the bottom. Replaced fuel filter and bled all lines to the injectors. With some persuasion I can get the engine to fire but I can't get the forward cylinder to fire consistently/evenly. The rear is steady and smooth but the forward is louder and more metallic sounding and will miss when the throttle is pushed and won't run at all at idle. Come to think about it, the engine has always had the loud tinny sound from I'm hearing from the front cylinder, I just assumed that's the way the engine sounded and you j30 guys were just gluttons for noise abuse but now that it's missing I can hear the rear cylinder firing on it's own and it's much smoother and quieter. Now I'm thinking injector? What's involved in replacing/tuning? Hope this thread helps someone else struggling with their engine.
Posted By: Rhapsody #348

Re: Engine Trouble - 06/18/14 03:16 AM

The problem is probably related to one of two items.

1. Injector nozzle not spraying a mist (clogged injector)
2. High pressure fuel pump output sending wrong amount of fuel to cylinder.

#1 can be fixed by removing the injector and taking it to a diesel shop so they can pop test, and if required replace the nozzle. They can shim the injector to meter the right amount of fuel. Pull them both and label which cylinder they are matched to. When replacing the injector, be sure to replace the mica insulator that fits between the injector and the head.

If that doesn't fix it, next try

#2 requires returning the high pressure pump to a Yanmar repair facility. They can rebuild the seals and setup the fuel rack for proper metering of fuel at all rpms. This requires special test equipment and is why the task needs to be done at the Yanmar repair center.

Refer to section 3 of the 2QM15 Service Manual located on the J/30 page under the menu Info, Diesel Engine Maintenance. This has detailed diagrams and rebuild procedures for the injector and fuel pump.
Posted By: JBiermann

Re: Engine Trouble - 06/21/14 10:19 PM

problem solved. Pulled the injector and brought it to a fellow club members shop where we pop tested it. The nozzle itself wouldn't even re seat itself after the first test, just stayed open spraying a little stream of fuel. So with the nozzle replaced with a salvaged nozzle from another old yanmar engine we got a successful test 1900 psi. I put the injector back in today and the engine runs better and quieter than it ever has. I am having some trouble getting the fuel line screws to reseat at the injector, a little diesel seems to be dribbling out, can I use teflon or locktight to get the threads to seal?

Thanks for all your help!

josh
Posted By: Rhapsody #348

Re: Engine Trouble - 06/22/14 02:00 AM

Josh,

Are these "banjo" type fittings with the copper washer gaskets like on my 2GM? If so, replace the copper washers.

I reread your post. The supply lines are threaded, the recirc lines are banjo fittings. Don't get any teflon tape in the flared section of the supply line, only on the threads. Ideally you should replace the leaking line as this is designed to seal with the flared fittings and is under extreme pressure.
Posted By: JBiermann

Re: Engine Trouble - 07/02/14 10:40 AM

The fuel lines seem to have seated themselves, no leakage this last trip. But it would seem the old engine has a new issue to be resolved, I'm thinking it's related. Engine starts smooth and settles into idle quickly but motoring back into the harbor I noticed some light grey/white smoke out of the exhaust. Then an engine alarm went off. I turned off the engine, sailed back to the mooring on the jib and engine started and ran normally when I started it on the mooring. What would the alarm indicate? Related to the smoke?
Posted By: Rhapsody #348

Re: Engine Trouble - 07/02/14 11:08 AM

It could be just steam from the exhaust, and potentially low water flow out the exhaust flashing the water to steam. Check the exhaust elbow to make sure it is clear. Is your engine raw water or fresh water cooled? Check the thermostat and the raw water pump impeller for raw water cooled engine.
Posted By: JBiermann

Re: Engine Trouble - 07/02/14 01:37 PM

Yeah, thermostat occurred to me but exhaust elbow is also a good idea, we've come full circle on this thread. I am going to replace both I suppose, couldn't hurt and the engine is old enough. Really paying for my sailing days this year. Thanks for all your advice.
Posted By: JBiermann

Re: Engine Trouble - 07/03/14 01:43 AM

Pulled the old thermostat, definitely rusty and corroded. New one is in and didn't overheat on the short trip back to the mooring. I'll put her through the paces on friday, hopefully this was it.
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