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Ask Dominick Your Own Question
Dominick, Marine Mechanic
Category: Boat
Satisfied Customers: 1009
Experience:  25 Years Experience as Mechanic, 20 Yrs Boat Yard Owner/Mechanic, Factory Certified
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I have an older 3208 NA 210 HP caterpillar in my commercial

Customer Question

I have an older 3208 NA 210 HP caterpillar in my commercial work boat. This week it starting losing high rpm power and was blowing black smoke out of the port side. We had an old Kenworth a long time ago with a 350 cummins and would do this and get lazy. Change the fuel filter and it would be fine. We changed the fuel filter but did nothing. I thought it dropped and injector. I started with one but decided to replace all injectors on that side since I had it opened anyway. Adjusted all the valves, bled out the injectors and started it up. It was a little rough starting naturally but picked up with no problem. Also when we bought the boat it had a pulley that was entirely too big for the salt water cooling pump for the wet exhaust. It was getting hot enough from the exhaust manifold on the port side that it burned out the rubber exhaust hose between the riser and the metal exhaust pipe to the stern. I need to check the impeller since I'm not seeing more was from the exhaust like I should. I took a test run and did increase loaded rpms but still very lazy and now billows black smoke from both exhausts. I lost my tach cable so I can't tell how many rpms its losing under power. Typically I can get 19 knots at full throttle but now only getting 10 to 12 knots. I use about 3 quarts of oil per week. I work 6 days a week for probably more than 12 hours a day. I feel this is minimal oil usage considering the age of the motor. Without being in gear she runs up to a high rpm with a little white smoke and no black smoke even at full throttle. I was told the heads had been remanufactured and had less than 300 hours on them. I have only had the boat in the water since February and probably ran the engine for less than 2500 to 3000 hours. Every time I have to go for a long sail to work I would run her up to full throttle and back down to about 2200 rpms. Normally it would only turn about 2500 to 2600 rpms at full throttle. I believe this to be in the size of the propeller since the engine is rated for 2800 rpms max. I can't figure out the loss of power and the large amount of black smoke at high rpms. The black smoke is constant under loaded high rpms. What can you suggest? I have not yet checked the air intake filter but I find it hard to belied its stopped up since it was new the last service at about 300 hours ago.
Submitted: 1 year ago.
Category: Boat
Expert:  K. Kergan replied 1 year ago.

Hi, Kerry again,

When a diesel smokes black, it's usually un-burnt fuel.

This could be caused by leaking injectors, bad compression or a bad turbo or blower.

A bad turbo will result in loss of power and black smoke.

Can you give me more details about your engine, turbo, blower, intercooler, etc.

Expert:  K. Kergan replied 1 year ago.


Customer: replied 1 year ago.
This motor is a 3208 natural it has no turbo and 4 new injectors on the right side as you look at the front of the motor. Exhaust is a wet exhaust and blows black smoke and loses power at high rpm under load
Expert:  K. Kergan replied 1 year ago.

So the side with new injectors is blowing black smoke at high RPM, is the black smoke the reason for the new injectors?

Expert:  K. Kergan replied 1 year ago.

I mean, was it blowing black smoke before the new injectors and this did not fix it?

Expert:  K. Kergan replied 1 year ago.

Read the question again, it sounds like the engine over-heated, you may have leaking head gaskets.

I think you should do a compression test.

Expert:  K. Kergan replied 1 year ago.

You said it was getting hot from the port manifold, does it still get hot or did you solve that?