White Smoke but Engine Runs Fine

[Ex-Calif]

How long have you had the boat?

Low power and white smoke with a little vibration could be a fouled prop. Ours does that about every 6 weeks.

[RBEmerson]

Given you've had problems with the injectors, yes, the pump should be re-built (by a reputable re-builder, and not just someone with a bench and a wrench or two). Since you didn't say how old the engine is or what the findings from the injector re-build are (that is, what clogged the injectors), there's the chance this work isn't needed. But chances are it is. Also, I trust you had all four injectors rebuilt. If something clogged three of four injectors, there's a good chance the fourth is on its way out, too.

[Chief Engineer]

I don't think we should compare apples (Yanmar) and Oranges (Volvo)

[Chief Engineer]

No......diesel injection pumps need to be sent to a shop.....and you really have to know what you are doing to re-install....

Originally Posted by hlemail

Just to add my 2 cents worth.

I had a similar problem, white smoke and engine running well.

When I took the 3 injectors off the Volvo 2003, they were not atomizing, and some only come out from 2 or 3 holes. Not all 4.

The injectors is being rebuilt now with new nozzles. A$ 105 each nozzle + A$ 40 per injector for labour and adjustment.

Hopefully after this fix, everything will be OK. The desel mechanic want me to disassemble the diesel pump as well. I can not imagine how much that will cost.

Do you think it is a good idea?

[hugosalt]

Cleaned bottom and prop last week when I first noticed problem..did'nt need, it was already clean from 3 weeks ago...bought new 24 years ago, estimate 800-1000 hours
on motor ...
Last night went through fuel system and added fresh diesel..seems to resolved 2 out of 3 problems...have full power back and motor is back to smooth running...but still
have white smoke(steam I think... disapates fast) when motor is warm and under load.

[RBEmerson]

Originally Posted by hugosalt

Cleaned bottom and prop last week when I first noticed problem..did'nt need, it was already clean from 3 weeks ago...bought new 24 years ago, estimate 800-1000 hours
on motor ...
Last night went through fuel system and added fresh diesel..seems to resolved 2 out of 3 problems...have full power back and motor is back to smooth running...but still
have white smoke(steam I think... disapates fast) when motor is warm and under load.

It is possible that all you're seeing is steam. Check the raw water flow to the mixing elbow and check the elbow for restriction - it could be that the mixing elbow's not seeing quite enough raw water to cool things.

[gs41escapade]

Hold your hand, or a piece of paper over the exhaust (not to block it just to catch the 'smoke') for 10 -15 seconds. Then examine and smell any residue. If it smells like diesel, then you have white smoke, not steam. Also examine the water behind the exhaust. Any shiny, oily slick? if so, its white smoke unburnt diesel.

[RBEmerson]

Good idea.

[hugosalt]

Thanks guys...took the exhaust hose off this past winter to inspect elbow, took good look, was not restricted and very little residue came out when I cleaned...,Water flow seems normal...
I took exterior temp readings yesterday..with motor warmed up,
@1500 rpm's but not under load..top head 134f..manifold 150f..
I think 130 is good for raw water cooled?...I pinned a paper towel to a piece of wood and held over exhaust(great minds think alike!) no diesel smell just wet...but very occasionally
I see a hint of oil in the water, I'll keep a close watch on a calm day.The white exhaust is slight but always there, when motor is warm. Hopefully can be addressed before becomes a big problem Thanks all...will be a few days before I can get back on board.
Will report back.

[theonecalledtom]

When we first got One Love we'd get steam above 2100 rpm. Looking at the way the water heater was plumbed into the cooling system there was a crimp in a tube. Re factoring that setup got us up to 2500 rpm before steam starts forming. I keep meaning to go through the water intake system and check the impeller but 80 hour work weeks leave little time and energy for play.

A few weekends ago I did have some play time and went skin diving in local kelp forests. Managed to wrap a tenacious piece around the prop and the engine started steaming at around 2k rpm again until we cleared it.

[hugosalt]

Chief, (if it comes to having to send out to rebuild
pump/injectors)
do I hear you saying don't re-install yourself unless
one does this for a living or close to...

[RBEmerson]

Originally Posted by hugosalt

[...]The white exhaust is slight but always there, when motor is warm. Hopefully can be addressed before becomes a big problem Thanks all...will be a few days before I can get back on board.
Will report back.

In which case, I'd let it go. Our Universal M40 also presents some steam / water vapor when running under load. The engine was gone over in June (valve train clearances dialed in and general inspection) and the injectors and pump were rebuilt a year ago. The mixing elbow was replaced recently. We're reasonably confident the engine's sound. Some days, steam happens.

[RBEmerson]

Originally Posted by hugosalt

Chief, (if it comes to having to send out to rebuild
pump/injectors)
do I hear you saying don't re-install yourself unless
one does this for a living or close to...

If you have the shop manual, injector replacement is DIY. The high pressure pump, however, is one I'd leave for the pros. Timing issues as well as knowing what to move and what to leave alone make this a job that takes some real training; it's not a place for OJT.

[Steve W]

On very humid days with cooler ambient temps, my diesel will exhaust some steam, even after it is up to operating temp and under load. Scares me every time it does this, but the engine temp is always normal, good flow and no leaks so I guess it has to be the right combination of humidity and temp. Noticed several other boats in the marina doing the same thing. Finally quit worrying about it.