Westerbeke 44B exhaust coming back through intake, running rough

[sailah]

Hi,

Sorry for my first post to be a HELP ME, but I'm really at my wits end here.

I laid up my otherwise perfectly running Westerbeke 44B last fall as I always do. Removed impeller, changed oil, zincs, ran antifreeze through cooling circuit etc.

This spring (today) I installed the impeller, changed the Racor, the secondary fuel filter on the engine. I did not bleed, Westerbeke claims its a self bleeding engine and I've never had an issue before.

I also changed the air filter. When I removed the filter it was nasty black and almost deformed. I found that strange. So I changed it with my spare.

Fire it up and it runs fine for maybe 2 minutes. Pumping water fine, running as expected. Suddenly it starts running rough and I can hear a change in the sound, gets much louder down below. I notice some smoke so I immediately shut it down.

I decide to bleed the fuel system so I do that at the filter and then at the pump. All good. I try to do the same while running at the injectors but the smoke was horrendous. I did manage to crack them all and bleed them but I don't think that's the problem.

Ran the engine again, and it will run. But it feels like one cylinder is not firing and it's blowing back the smoke through the intake.

Any ideas what I'm looking at? Stuck valve? I can't think of how exhaust would come back through intake otherwise.

Any and all opinions are welcome. I'm pretty hands on, have rebuilt motorcycle engines. I have no problems tearing into it I just want to make sure I'm not overlooking something basic first.

The dirty air filter from last season has me concerned. It exhibited none of these symptoms last fall when put away however ran like the swiss watch it always has.

I'm meticulous about my fuel system I run a 2 cartridge fuel polisher and have never had a fuel problem ever.

[deblen]

suspect intermittant sticky intake valve.

Remove valve cover & roll engine by hand while watching rocker arms.

Use a hammer & piece of hardwood to gently tap each rocker & make valve bounce. Apply WD40 or your favourite penetrating fluid to top of valve stem. It may take awhile to work it's way down thru the valve seal & thru the valve bushing.
It is not uncommon for a valve stem to develop a light coat of rust during storage if that valve is open.

If you don't understand what I'm saying,get help

Cheers / Len

[sailah]

Hi Len,

I totally get you thanks. I'll work on it this week, and report back. I suspected some type of valve issue after the bleeding did not change things.

When I stuck my finger in the intake manifold it was wet with diesel fuel/exhaust like black paint.

Thanks

Pete

[Diesel Bill]

Sounds like your on the right track. I would also suspect a stuck valve or possibly a broken part in the valve train. If the intake valve sticks open there might be piston to valve contact. If the valve got bent it can't seat after that and could cause the symptoms you mentioned.
Good luck and let us know what you find so as to help all of us.

[sailah]

Thanks Bill, I'm hoping there wasn't contact. I've rebuilt some engines in my day, the harder problem is that I don't really have a lot of time to dig into a rebuild. The engine was a marinized Mitsubishi S4L2 block which is a fairly common industrial power unit. Having a hard time finding anyone with parts should I need them. Mack Boring is the dealer for industrial Mitsubishi so I hope they have these. Getting parts from Westerbeke, and they are pretty local to me, I practically need a mortgage to buy a gasket.

Will remove the rocker cover and see what I see this week.

I also read that a corroded mixing elbow could cause the same issues. It was pumping water fine, both while it was running perfectly and when it instantly changed. I'll remove that elbow and check the condition. westerbeke does have new ones should I need it. It's an aluminum elbow.

This whole thing bothers me because I take fastidious care of that engine, I'm neurotic about clean fuel, built a custom fuel polisher with 2 large filter elements and constantly polish fuel under power. Maybe I'm being too nice with it and loving it to death. 3000rpm cruise for you now buddy!

[GILow]

I'd also check the crankcase breather for excessive blow past, such as you'd get from a cracked ring. Depending on the pipe arrangement it can feed crud back into the intake, often directly behind the air filter, or even on the air filter housing. That can then produce the symptoms you are seeing of oil and crap in the intake manifold.

[sailah]

Interesting. Def possible.

When I stuck my finger in the intake it was jet black and oily. I want to say it was half burned diesel sooty, but it could very well have been diesel.

Man my mind is just going to the worst places right now and I can't stop it.

I should probably procure a compression tester and maybe do a leak down test.

I'm really hoping for something simple...

[GordMay]

Greetings and welcome aboard the CF, sailah.

[GILow]

I've got my fingers crossed for you. I am all too familiar with the sinking feeling that can accompany engine problems.

[sailah]

Originally Posted by GILow

I've got my fingers crossed for you. I am all too familiar with the sinking feeling that can accompany engine problems.

It's the curse of being your own mechanic. Sometimes ignorance is bliss

Thanks for the welcome Gord!

[GILow]

Originally Posted by sailah

It's the curse of being your own mechanic. Sometimes ignorance is bliss

!

Yes, sometimes it is... at least, as long as the engine keeps turning.

But reading what people go through when they are not lucky enough to be able to do their own engine work is enough to make me feel better about the extra angst I suffer from knowing EXACTLY what is wrong with my engine.

On balance, I'd say be grateful that you are your own mechanic....

And keep a bottle of industrial strength hand cleaner on board. :^)

[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

[Kita]

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

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

[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.

[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?