Westerbeke 44B exhaust coming back through intake, running rough

[sailah]

Yeah I'm starting to feel that there is going to be further surgery involved.

A diesel mechanic friend of mine I texted this morning says he thinks it might be the gear on the injector pump sheared the key and is now firing on the intake stroke. While I can't discount that it doesn't seem like the most likely event. I still keep coming back to what I found with the air filter, this is what I found before firing it this spring. So what had happened was happening in the fall. Engine was not smoking or doing anything odd that I noticed.





I plan to get a compression tester and do that while everything is still bolted on and intact. Will also verify condition of glow plugs. Will check pump timing and see if it's correct.

I found the service manual from Mitsubishi with all the specs in it and also Mack Boring has most of the gasket stuff in stock so that has my anxiety level down a couple notches.

All that I can verify before cracking things open. If I do find a lot of buildup on the valves it might be perfect timing to correct the pitch on the MaxProp. I seem to recall on a clean bottom it wouldn't totally max out the 3000 rpms. Close but maybe I need to adjust that. Also guess i should be running it harder.

[sailah]

Originally Posted by a64pilot

I'm betting stuck valve, and I'd want to pull the head and have the head done at a machine shop, stuck valves end up being dropped valves. Easy fix now, but if it swallows a valve, that is bad, real bad.
Besides head off you can get a real good feeling as to how much cylinder wear you have too.

With the very tight tolerances on Diesels, its almost certain that the piston has kissed that valve, likely bent it, next step is the head coming off the valve

Thanks good advise. I just recently did all the valves on my tractor, so I'm well versed in this. Never done a diesel before, assume it's reasonably similar. I'm hoping to do some more testing before I take the head off to see where our baseline compression numbers are.

Originally Posted by Kita

Listen to this man he knows exactly what's going on I agree one hundred percent

Thanks

Originally Posted by Cheechako

Are you sure all of the deformed air filter was intact? It didnt suck part into the engine I hope. Take the valve cover off and check that all pushrods are on the rockers properly. If they then run it or crank it to see that all valves go up and down.
-If just a sticky valve and it frees up you may be ok for the season.
-I have had one Perkins throw a push rod off the rocker entirely. It was laying alongside the rocker when we pulled the cover. Hard to figure how it did that. Everything else was fine. The motor actually rand pretty smooth.. but that one cylinder was obviously a problem.

Thanks, have a look at the filter pics. Now that I look at them the part with the broken wire mesh faces the intake. And it broke somehow. I did not see those pieces in the airbox. Can't remember if they are plastic or metal. All the soot and smoke are on the clean air side, not sure how that happened.

When I ran the engine yesterday with a new filter you could see the exhaust stain on the mesh side of the filter. Which is opposite how it is now.

Originally Posted by Valmika

I have a westerbeke 42B and had a similar issue. If the soot is coming back it could be a stuck intake valve but I would also look at a stuck injector. In the open position it will just keep feeding fuel into the cylinder and will create a black soot the will lay on the water like an oil slick. That black smoke is unburned fuel Is it only coming through the air filter or also out the exhaust?

Thanks, will probably be pulling the injectors and sending them off to be cleaned.

[Cheechako]

Originally Posted by Valmika

I have a westerbeke 42B and had a similar issue. If the soot is coming back it could be a stuck intake valve but I would also look at a stuck injector. In the open position it will just keep feeding fuel into the cylinder and will create a black soot the will lay on the water like an oil slick. That black smoke is unburned fuel Is it only coming through the air filter or also out the exhaust?

Yes, and check the oil in the sump... it may be rising!

[Cheechako]

Just get rid of that filter, you don't need it in a boat. I've never had a diesel with a filter on the intake other than a screen. Most not even that. Not like it's running on a dusty road.

[sailah]

Originally Posted by Valmika

I have a westerbeke 42B and had a similar issue. If the soot is coming back it could be a stuck intake valve but I would also look at a stuck injector. In the open position it will just keep feeding fuel into the cylinder and will create a black soot the will lay on the water like an oil slick. That black smoke is unburned fuel Is it only coming through the air filter or also out the exhaust?

Sorry didn't realize I didn't answer your question.

The smoke was only coming from intake, not the exhaust. I didn't run long enough to really check the exhaust but I did check at first start up to ensure I was pumping water. I did not notice any smoke, nor did I notice any last year in either normal crusing, on the way to get hauled or on the hard. This engine has always worked 100%, never a lick of trouble.

The timing of everything including the air filter has me puzzled.

Not a single sign of not running 100% last year but the evidence points to otherwise on the filter.

At first startup this spring engine ran fine for 2 minutes, then all of a sudden it didn't. black smoke etc.

So I think the signs were there last year and I missed them and now something else just decided it no longer wants to cooperate hence the smoke.

Reading the Mitsubishi service manual now, much more comprehensive than the Westerbeke I have.

[a64pilot]

Originally Posted by Cheechako

-I have had one Perkins throw a push rod off the rocker entirely. It was laying alongside the rocker when we pulled the cover. Hard to figure how it did that. Everything else was fine. The motor actually rand pretty smooth.. but that one cylinder was obviously a problem.

It did that because the valve stuck, when it was stuck open, there was a whole lot of play, enough so that the push rod could fall out of the indent in the rocker arm.
Often they fall out only part way, then get bent when they try to open the valve further than it can because the valve spring stacks up.

You got lucky, the valve freed up and didn't stick again, it happens.
Google "Lycoming morning sickness" for a very good explanation of valve sticking

[a64pilot]

Sailah, a very quick way to determine if you likely have a bent valve is to check valve adjustment, if you find one that is real loose it may be bent. See a bent valve won't seat properly, and therefore it sticks down more than it should, and this will show up as a way loose valve.

[sailah]

Originally Posted by a64pilot

Sailah, a very quick way to determine if you likely have a bent valve is to check valve adjustment, if you find one that is real loose it may be bent. See a bent valve won't seat properly, and therefore it sticks down more than it should, and this will show up as a way loose valve.

Nice tip thanks.

I just downloaded, printed, hole punched, and put fancy tabs on the factory Mitsubishi service manual. That has calmed the OCD side in me

My wife and kids are leaving for Florida this week so I'll have plenty of evening working time.

I'm loaded for bear now!!

[Valmika]

Originally Posted by sailah

Yeah I'm starting to feel that there is going to be further surgery involved.

A diesel mechanic friend of mine I texted this morning says he thinks it might be the gear on the injector pump sheared the key and is now firing on the intake stroke. While I can't discount that it doesn't seem like the most likely event. I still keep coming back to what I found with the air filter, this is what I found before firing it this spring. So what had happened was happening in the fall. Engine was not smoking or doing anything odd that I noticed.





I plan to get a compression tester and do that while everything is still bolted on and intact. Will also verify condition of glow plugs. Will check pump timing and see if it's correct.

I found the service manual from Mitsubishi with all the specs in it and also Mack Boring has most of the gasket stuff in stock so that has my anxiety level down a couple notches.

All that I can verify before cracking things open. If I do find a lot of buildup on the valves it might be perfect timing to correct the pitch on the MaxProp. I seem to recall on a clean bottom it wouldn't totally max out the 3000 rpms. Close but maybe I need to adjust that. Also guess i should be running it harder.

Could you send me a link to the Mitsubusi Manual.. I have been looking for one.

[sailah]

Originally Posted by Valmika

Could you send me a link to the Mitsubusi Manual.. I have been looking for one.

I don't know if it's OK to post links so I'll PM it to you.

[a64pilot]

So long as it's not an illegal download, I think it's OK to post

[sailah]

Ok if you Google mitsubishi S4L2 service manual it will come up on a Russian tractor dealer site. Down loaded it and it is perfectly fine.

[etterridge]

Hello sailah

When buying Mitsubishi parts your best options are NOT westerbeke OR Mitsubishi. A quick Google Search just turned up tractor suppliers in the USA and a pile of Asian suppliers in Alibaba. Com. For your engine

You should find a good quality full gasket set on Alibaba in The $100.00 price range.

I just purchased a Mitsubishi K4D head gasket from NCW Tractor Parts in Law Vegas for $89.00 including shipping. The part arrives in four days.
I recommend them.

A few years ago I bought 4 pistons, 4 sets of rings, 4 prs of big end bearings, a full gasket set and a used con Rod for $330.00 from an Alibaba supplier. Freight was $90.00 extra and the parts arrived in 5 days. The parts all fit fine and we had them in the engine and running, at anchor in the far Bahamas, in only a few days.

On that latter occasion our symptoms were similar to yours except that we had a fog of glycol in the engine compartment too. The problem was a cracked piston. It failed due to a poorly torqued head gasket seeping antifreeze into two cylinders.

The Alibaba supplier was Bee Auto, also well recommended.

Good luck from another DIY mechanic.

P. S. I had not rebuilt an engine in decades so I prepped by studying YouTube videos. I learned some good tricks too!

[Compass790]

Good that you are on the right track knowing the industrial diesel your engine is based on. You may find the crossover parts are 1/4 the price or less even.Other posts have covered the most likely cause very well. I'll be interested to read what you find. Welcome to the forum & hope for your sake the penetrating oil works :-)

[sailah]

So I'm on the boat now. Popped the valve cover off and nothing amiss. Decided to remove glow plugs as they are in the way. Reading the manual I should have 0.55 ohms between terminal and body.

I have zilch. On all 4. Using a fluke meter. I put them on my lab power supply and can't get them to take a current at all.

Someone tell me I'm doing it wrong or could all 4 be bad? Seems unlikely. I have my meter set correctly and even zeroed the lead resistance on the fluke.

Would this be a reason?

The engine was starting.