Cummins 555 Turbo Smoking

My Riviera Bluewater has Cummins 555 Turbos and the port engine smokes excessively at 1800 revs. can I get some advise on the cause so I can get it fixed.
Had it looked at by several repairers and they have different ideas. the engine hours is 1500.
the engine starts without a problem and has no oil slick on the water when berthed. goes well and no issues at 1200 rev but gets smoke at 1500 and then real bad at 1800 and beyond.
please help with any ideas .

The colour of the smoke is critical. If dark or black you are likely having air restriction or lack of air issues. Turbo would be probable cause. I had those motors in a prior boat and no issues at all and are good engines if not thrashed.


check how well your turbo spins. If sticky then free it up or replace it. You should also look at the exhaust arrangement as you may be getting a bad turbo from seawater from exhaust cooling and leaking back and rusting the hot side of the turn. If you have wet risers or cans I would almost expect this issue at some stage.

Not enough air, too much fuel or overload


check air filter and turbo for free spinning. Something could be on the prop causing over load. Will it hit proper wot?
Last is a bad injector but check that last.

I totally agree with the previous posters. The problem is not enough air or rarely too much fuel. Lack of air is often caused by a poorly performing turbo.


It is easy to check the turbo. A quick check is to remove the air cleaner and reach inside the inlet of the turbo and see if the blades spin easily with a flick of your finger. With the smoke that you describe I suspect you will find it stuck or turning roughly.


If so then you need to rebuild or replace the tubo but you also need to find out why. This doesn't happen to turbos for no reason and the reason as stated above is usually sea water backing up into a poorly designed exhaust system.


If the turbo spins freely, then it takes a bit more work to fully check it out. You have to remove the exhaust elbow and mixer from the turbo and look inside the exhaust throat. If you see heavy rust and corrosion, then you have had water in it and it needs to be fixed as above. Also measure the blade tip to housing clearance. Should be 0.010" or less. Any more is due to corrosion which will reduce turbo performance and lead to the smoking that you observed.


If all of that checks out ok then you may have an exhaust restriction, so take a look at the mixer while it is off. Also he air cleaner or the air cooler might be plugged.


David


David

Definitely check the air filter first.

Blue smoke?
Black smoke?
White smoke?

Need to know...

The smoke colour is grey/black. hope this helps.

message me if you want the best 555 mechanic and Cummins mech in Aus. He knows this motor better than anyone. You need to follow all advice given so far. Or simply open your wallet wide and start handing out 100s to those who know nothing but will "trouble shoot"

Definitely check your filter, it sounds like you are over fueling. Are the 'throttles' split? Do you need more power to sync the engines? Could be the turbo, but go for the easiest first. Is your transmission/ running gear happy? No barnacles, cutlass bearing good, transmission oil recent?

Has it had all its regular maintenance? Oil and filter, coolant checked for condition and new filter, valves set, fuel filters changed?

Have you ever had the injectors checked and cleaned?

Is it possible that you picked up something in your wheel?

Do you have the Cummins manual? It also has some troubleshooting procedures.

I would do all the required regular maintenance first; if it has been done and none of the other things mentioned are at fault, then I would get a mechanic in, but not til you have done all the work first as it is expensive to pay out for what you can do.

Good luck.

Thanks guys for your response. I will do the things you have all said and let you know the outcome next week

If Bohans has a name of a good mechanic knowledgeable with the 555 then pay attention and take him up on his offer. He had those engines.

I'll second, third and whatever the rest of the advice .

Be sure the air cleaner is clean [REPLACE IT], the turbo doesn't have corrosion issues, is not sticky or rough spinning. The exhaust elbow is not corroded and restricted.

Looking at an air filter is not good enough as often it can be plugged with dirt that doesn't show up visually.

One more thing is the exhaust hose. If exhaust cannot get out air cannot get in. Not common but can be a cause.

Check the affected prop as a bag, rope or other trash can overload the engine which will cause black smoking.

I have had dirty fuel filters acting like to much fuel so allways change fuel filters clean air filters then ck for problems