smoky exhaust

[pcatterall]

Following our shake down cruise ( after a lazy year in the French canals) several problems are apparent. I will raise my questions one by one so as not to be too much of a bother to the experts.

In the canals and now at sea the exhaust has been very smoky, you only see it at start up but the transom becomes very dirty very soon.

Oil consumtion on our 4108 is minimal so I assume that it is unburnt diesel, I have checked and cleaned the ( rather basic) air filter and the air supply is the same as when the boat was built.

I suspect that the injectors may be the cause but will value your good advice.

If this is the case what are my options?
might some kind of aditive clean them out?
should I locate some new ones and swap them over?

many thanks.

 

[Marsupial]

Following our shake down cruise ( after a lazy year in the French canals) several problems are apparent. I will raise my questions one by one so as not to be too much of a bother to the experts.

In the canals and now at sea the exhaust has been very smoky, you only see it at start up but the transom becomes very dirty very soon.

Oil consumtion on our 4108 is minimal so I assume that it is unburnt diesel, I have checked and cleaned the ( rather basic) air filter and the air supply is the same as when the boat was built.

I suspect that the injectors may be the cause but will value your good advice.

If this is the case what are my options?
might some kind of aditive clean them out?
should I locate some new ones and swap them over?

many thanks.

What colour smoke?

After a year at very slow speeds a few hours at 75% full rpm would not do any harm - after we know what colour the smoke is

 

[pcatterall]

What colour smoke?

After a year at very slow speeds a few hours at 75% full rpm would not do any harm - after we know what colour the smoke is

Blackish and the deposit is black. We have spent quite a few hours at cruising revs and there is no improvement.

 

[causeway]

Try the usual Italian tune up, maybe with some injector cleaner in the tank? Bound to be worth a go

 

[prv]

Before doing anything difficult or expensive, surely worth trying an Italian tuneup - motor at max revs for half an hour or so. This burns up carbon deposits in the engine, and reduced the black smoke quite a bit when I tried it on Kindred Spirit.

Pete

 

[NUTMEG]

Is the prop clean? We had barnies on a prop once that caused the engine to smoke at high revs. Thinking being that weed/barnies prevent the engine from revving freely = lots of throttle = lack of revs = unburnt deisel = black smoke at high rev/throttle setting.

We cleaned the prop and bingo, no more smoke.

Just a thought.

 

[Marsupial]

Yes clean the prop then run the boat at 75% of Max revs for a few hours.

 

[prv]

Yes clean the prop then run the boat at 75% of Max revs for a few hours.

We used to cruise at 80% of Max Continuous, so 75% of anything wouldn't have been much of a blast-out. For that, I really would push the throttle to the stop. A 2GM20, for instance, is rated for at least an hour in that mode; I gave it 20 or 30 minutes. Obviously let the engine get well up to temperature before you open the taps all the way.

Pete

 

[Marsupial]

By my calculations that's only a difference of 20rpm! I was carefully to say Max rpm not max continuous just in case the op did not know the difference.


I'll crawl back into my burrow, bye now see you next year may be.

 

[Hoolie]

Our Perkins smoked A LOT on start up until I did a top end refurb that included the valve guide oil seals. The oil seeps through into the cylinders from the camshaft area when the engine is not running.

After a few years it has started to smoke a bit but proprietary anti-smoke additive cures it completely.