Attempt to Clean Injectors on Yanmar

[andrewuaus]

Hello.
You guys have a beautiful forum, I have learned a lot from here during last couple of years.
Now, after obtaining a real cruising boat, I dared to join.
Here is what prompted me.

I have black smoke and sludge coming from the exhaust when it is above 2000 rpm, so I decided to try to clean the injectors.

According to what is written on the bottle I filled the primary filter with "Lucas Upper Cylinder Lubricant", after approximately 7 minutes the engine (Yanmar 3HM35F) coughed a couple of times and stopped.

I pushed the decompression lever and cranked the diesel several times for a couple of minutes total, then next morning I closed the decompression lever and tried to crank the engine but it didn't turn a bit. The batteries were fully charged.

Then I opened the decompression lever, attached a rope to it and closed it while cranking then it worked, the diesel didn't start but the starter was able to turn the engine with decompression lever closed.

What caused that engine stalling?
Is there any chance that water could get inside the cylinders after prolonged running without compression?

What is the best way to "evacuate" Lucas from the fuel system ?

Thank you.
Andrew

[djmarchand]

Post your problem over on boatdiesel.com in the Yanmar section.

I suspect that the heavy oil didn't burn well and much of it stayed behind in the cylinder until it hydrolocked the engine. It is possible that you bent a connecting rod.

The boatdiesel gurus should be able to help you.

David

[Jim Cate]

To answer your query:
Yes, prolonged cranking without the engine starting can bring water into the cylinders. While you are cranking, the water pump continues to push water through the engine and into the exhaust system. When the engine is running, the exhaust gasses blow the water on out of the boat, but when it isn't running the water collects in the water-lift (if fitted) and various hoses, etc. Eventually it fills it up and then the water can drain back into the cylinder(s) via an open exhaust valve.

I hope that you didn't damage anything serious trying to turn over a hydraulic locked engine. Doesn't always happen, so good luck!

Cheers,

Jim

[Chief Engineer]

Why people think you can clean injectors with "magic" additives is beyond me.....Please don't take it personally.

It sounds like you over cranked the engine, filled the exhaust line with water and hydrolocked it.

Drain the exhaust system.....even if it means taking the exhaust hose off

Get all that "magic stuff out of your fuel system

Open the decompression lever and hand crank the engine over.

If it doesn't budge....don't force it....you probably have a bent con-rod.

If it does move smoothly.....pull the injectors and send them out for refurbishing........you may have to pull the injection pump also....keep us posted.

[never monday]

I'm not concerned with the Lucas in the fuel. It will burn. I am concerned about the condition of the exhaust elbow, and fouling of the bottom/prop.

Most likely you had a reversion of water due to the exhaust elbow restriction.

[andrewuaus]

Originally Posted by Jim Cate

To answer your query:
Yes, prolonged cranking without the engine starting can bring water into the cylinders. While you are cranking, the water pump continues to push water through the engine and into the exhaust system. When the engine is running, the exhaust gasses blow the water on out of the boat, but when it isn't running the water collects in the water-lift (if fitted) and various hoses, etc. Eventually it fills it up and then the water can drain back into the cylinder(s) via an open exhaust valve.

I hope that you didn't damage anything serious trying to turn over a hydraulic locked engine. Doesn't always happen, so good luck!

Cheers,

Jim

Thank you very much Sir.
I wish I knew it before. I'd better close the cooling water intake.

[andrewuaus]

Originally Posted by Chief Engineer

Why people think you can clean injectors with "magic" additives is beyond me.....Please don't take it personally.

Why not? Carburetor Cleaner does very good job cleaning my guns. Additive is cheap and easy to use why not to try it?

[perchance]

I have to agree with Chief engineer regarding engine rebuild in a can and other magic fluids. Diesel injectors and pumps are precision pieces of equipment and don't take kindly to dirt or water. Like any mechanical device they are subject to wear and will go out of tolerance over time. No amount of magic fluid will correct that. Take them to a competent diesel shop and have the cleaned and pop tested and you will have many hours of trouble free operation providing you use clean dry fuel.

[andrewuaus]

Originally Posted by never monday

I'm not concerned with the Lucas in the fuel. It will burn. I am concerned about the condition of the exhaust elbow, and fouling of the bottom/prop.

Most likely you had a reversion of water due to the exhaust elbow restriction.

After meditating a half of a night on the subject I've concluded that you have pinpointed the problem.
Experience is great thing!

My bottom is not perfectly clean, and the mixing elbow was clogged so water stopped coming from it. I have cleaned with piece of electric fish tape. There is an aluminum plate on top of it, so I've drilled a hole in it, and then ran that tape up and down, it did the trick. That happened BEFORE
and when I "cleaned" injectors water was coming through OK. Then I threaded the hole and put a stainless bolt in it wrapped with Teflon tape. It works well now but the mixing elbow needs to be replaced.

The biggest false assumption I made was the idea that the diesel stopped because of Lucas but actually some air got inside the fuel system when I opened primary filter.

I realized that only after looking up a schematic picture of primary fuel filter in Nigel Caldel book. if you open it air inevitably gets inside.

Then I thought that extended cranking would eliminate that additive from fuel system, I shouldn't do it at all.

To fix the problem I just bleeded the air and diesel started right away.

I ran it on different RPMs for 20 minutes, then changed oil and ran it again for 20 mins.

I cannot say if there are additional knocking sounds, the engine used to be noisy before.

What are the symptoms of a bent piston rod?

All my previous boats had either electric motor or gas outboard, that is my first encounter with a diesel.

Many, many thanks.

[donradcliffe]

Congratulations on getting her going again! I suspect you have learned a lot. I wouldn't worry too much about bent rods if it runs OK.

[clockwork orange]

Ok,not boat related but diesel related,ive never been a big believer of majic potions either but a couple of months ago i bought a 19ft pacific cat on ebay,it was in Fairfax, VA, me in Minnesota,no problem, we drove out with my old TDI Passat and towed it back.Since most of my driving is in town,short hops i figured it would be a good opportunity to run some power service diesel kleen through the fuel system as i would be going through a few tanks in a short period.I topped up the tank before leaving and figured my mileage which was 34mpg,all in town and noted it was the worst tank of the year thus far,anyway the diesel kleen claimed an increase in mileage of up to 8%,well the first tank took us 750 miles with 3.5 gals still in the tank, 51mpg,next 46mpg with some towing,3rd tank down to 30mpg which i thought was pretty good towing a sizeable beachcat through the mountains of west Virginia,the next few tanks were in the 28-29 range with strong crosswind and then headwinds,supprisingly the worst tank was the last in perfect conditions,no mountains calm winds 27mpg,wtf? anyway my first tank of in town driving after getting home yielded 37.5mpg a 12% increase over the last tank before we left,the majic potion lived up to its claims,subsequent tanks have remained in the 36-38 range, i dont know, maybe the car just liked to be worked,i have noticed a bit more smoking since the trip but hey,its got a quarter million miles on it,im not complaining.
Steve.