BUIZILLA

it wouldn't run at all if this tripped...

see my post on your other forum area question

VetteLT193

Had a pair of 6-71's with a problem with the fuel line on one engine (single tank boat, 45 Viking). It was aerating the fuel. Most boats run separate lines all the way to the filter. Many boats run separate tanks too.

On a 42 Ocean SS we had a problem with a single engine (6-71's again, two tanks) where one side sucked up crap (algae probably) and the other didn't. we were running back from the Bahamas and were pretty low on fuel, the side with the problem was the same tank the Generator ran on, it was lower than the other.

On a 32 Pursuit with 3208 CAT engines, a similar problem with crap in the tank. On that boat both engines would go down eventually. We ran some kind of algae eater in the tanks and it actually caused the problem.

In all cases it was an easy fuel filter check... I at least like to knock the easy stuff out first. And in all cases above, black smoke.

sector

Excessive black smoke is from lack of air, not lack of fuel. Two cycle Detrioits will definitly run with the emergency flap closed, won't rev up very much and smoke bad. One other thing, if the emergency stop is OK check the air box covers under the exhaust manifolds. If one or more are loose it will rev OK but smoke bad and be low on power.

VetteLT193

I agree with the black smoke comment. usually white smoke == lack of fuel and black == lack of air BUT I can tell you from experience that it isn't so cut and dry.

I am speculating that there are cases during a lean condition the turbo spools down causing a rich condition. I've only personally seen Detroits blow white smoke on startup and maybe a puff of white during throttle up. Every other time the engine gets out of whack for any reason caused black smoke.

blkhorse

black smoke= not enough air or too much fuel

I have never seen a 92 series with a mechanical emerg stop(flap) they are on 71 series(no turbo). when was the last time it was tuned? rack,inj timing gov. gap and valve's set

is black smoke on accel or at steady throttle?

45sonic

OK, after picking the boat up this weekend here is what was found.

Checked shut off valve on turbo. It is in the open position.

Pulled air cleaners off both engines. Checked turbos. Port engine turbo blades are clean and shiny and spin freely. Starboard engine turbo blades are black/sooty/oily but spin freely. Switched air filters to opposite engines.

Did not get a chance to change fuel filters.

Smoke appears on take off and stays consistant while running.

29Firefox

What is the exact model designation? If it ends with an "A" the engine is equiped with aftercooler. It could be clogged. You will have to pull the blower to get to it.

Biggus

Old thread, wonder what was the issue????

MF

I had once a friend with a LOT of smoke, cheked and the problem were some injectors. Had the same problem with my father's Cummins VT 903 M, registered and all went ok.

Hope this hepls.