Yanmar Smoking and Making Oil

[Cheechako]

You've had the same experience i had in the carribean as noted in one of my earlier posts....went through 3 mechanics.. spent a lot of money (not as much as you!) and finally got a good mechanic who knew his stuff. DONT fix the one cylinder. Get an over haul, new pistons and rings on all cylinders and the head rebuilt. or replace the engine (non turbo!!) then relax and cruise!

[Laidback]

This Model Yanmar has no cylinder liners - which means if the bore sizes are still within specified limits, and if space allows, the repairs can be carried out without removing the engine. If one or more cylinders require re-boring then the engine will need taking out to an engine shop.
The Compression shown for one cylinder is indicative that the rings rusted into the piston grooves during the engine lay-up - if this is the fault then it may be possible to re-ring the piston with a new set of rings; at worst new rings and piston.

[sandspur]

Most likely they will find #1 cyl wiped out from over fueling do to the bad inj pump

[sigmasailor]

OK, I guess your previous mechanic managed to get the injectors right after all.
I was also wondering by the large volume of diesel in the oil; now that we have some real data it does make sense; either the lifting pump or injection pump could have caused it. I don't believe the rings failed because of too much injected fuel. That's the beauty of diesel engines; you cannot really overload them; they do start smoking but will not destroy themselves quickly when they get too much fuel.

I guess your #1 cylinder is bad luck. I would recommend to pull all the pistons out while the head is off for close inspection.

If the bearings are OK (why not?) an overhaul would be cheaper than a new engine.

[Charlie]

What a difference a good mechanic makes. Sounds like you have your direction now Terry. I know you will figure out how to make all this work. You are a problem solver. Sorry you had to go thru all of this but at least it happened in the states rather than in the Bahamas. Settle the family in to some fun and entertainment and then have at the engine. Good luck.

[never monday]

Originally Posted by Cheechako

DONT fix the one cylinder. Get an over haul, new pistons and rings on all cylinders and the head rebuilt. or replace the engine (non turbo!!) then relax and cruise!

what he said

[DennisDW]

Congrats on the diagnosis and change of venue. Going of a sail is a breath of fresh air!

I'd suggest doing the rebuild in stages. First the cylinder, then the injection pump if needed.

You might just be getting all that extra fuel in the oil running past the bad rings. It won't hurt to do one thing at a time and it could spread out the cost a bit.

Thanks for your keeping us update.
Your faithful groupies,
Dennis et al

[Gene :^)]

That is great that you found someone and got actual numbers/info.

Of course the trip itself also helped as it showed definitively that the fuel contamination was still occurring and was massive.

Since you have a mechanic that seems competent, I would just do the entire job. I really hope you get some credit on the turbo.

If you want to stay on a budget and "rebuild in stages" as DennisDW suggests... I would do the reverse of his suggestion. Change the injection pump first since that is the real problem. The cylinder with low compression is "a" problem but not "the" problem. As your test showed, it is still contributing power (engine slowed when injector loosened). Maybe the cylinder could be salvaged with a soak in transmission fluid and then run for a while to free up the rings (if they are stuck rather than broken). Could probably run for years with low compression.

I still vote to fix it all now and get it over with.

[Laidback]

In June 2009 the Injector pump was reportedly running to specification - It was confirmed that it was NOT adjusted, repaired, altered or modified during the period June 2009 until the present day. During conducted tests the engine out of gear achieved 4,000 RPM. Is it likely that the injector pump is faulty ? WE do have recent evidence that the cylinder # 1 is not giving expected PSI in the the range 430 >> 470 PSI.
Would it not be logical to fix the identified problem in number # 1 Cylinder ??? before moving to something else!

[Gene :^)]

Well, I still vote to fix it all at once, but I like to learn so it would be interesting to hear what the mechanic thinks... Tspringer, could you pose some questions to him?

Which problem is causing the black smoke and low RPM?

Did the bad injection pump wreck the cylinder by over fueling and is still over fueling causing black smoke and loss off power.

Is the fuel being made by just washing past the rings or does he think the pump is leaking internally?

Or is the low compression making the black smoke and low RPM?

If he were to only fix one of the two problems, which first? Would it be the low compression or the injection pump?

Basically get his idea of the sequence of events. What went wrong and what caused what?

[promax]

If there was a large volume of fuel being dumped in no 1 cyl perhaps that cylinder could have hydrolocked and hurt that piston-rings set

[sww914]

There's no way I would fix one cylinder on an engine that's had a lot of fuel in the crankcase or on an engine with a lot of time on it. This has had both. I would rebuild the existing engine and injection pump if time permits. A repower is likely to have it's own complications due to slight differences in the extremities, it might look like it will save time but maybe not as much as it looked like on the front end. I would not set out on a cruise with my family knowing that the engine is compromised.

[ChuckSK]

Let's assume 1 gallon per hour for 10 hours divided by 4 cylinders yields 2 1/2 gallons of fuel being pumped into the #1 cylinder. If there was insufficient compression to ignite the fuel, it had to go somewhere. 2 or 3 quarts running past the rings doesn't seem unreasonable. Why was the injection pump determined to be faulty?

Chuck

[Cheechako]

the good mechanic i finally found insisted on replacing the pistons and insisted on doing all cylinders...not just the bad one. he's the one who got it right so I did what he said to do. please dont make the mistake of fixing one cylinder and then going through this again. Take a deep breath.... it's a lightweight engine with 4000+ hours on it...it's a turbo to boot.... an injection pump is like more $ than the turbo you already bought right? In order to do this right you need an injection pump, an overhaul including head rebuild and you will still have some 4000+ hour parts in the engine.... How cruddy is the inside o f the engine? It should really be removed from the boat and boiled out..is it possible to resell the near new turbo and just reengine? If a new engine is 10K is a rebuild 5K...maybe it's worth rebuilding then...

[Laidback]

Was it Confucius who said "If its not broke, don't fix it !"