CUMMINS 6cta 8.3 black smoke

[Kyriakos Kostarelos]

I just purchased a 1997 TIARA 3500 express with CUMMINS 6cta. We noticed that that there was a lot of black smoke coming out mainly when the boat goes to plane. After a 4 hours trip both sides of the hull was black!!

Engines have 1200 hours and they have only 50 hours after a big service (the port one did a major repair, and the starboard a big service) two years ago. The boat was in the dock for the last 2 years and we find that aftercoolers had salt and corrosion. We repair it but after the next sea trial, the black smoke continues.

Do anyone has an idea how should we move on ?

Topic

[Tony Athens]

I want to SEE both aftercoolers along good pics of the engines -Mechanic made aftercooler ???? –NEED Pictures from all around the engine room, all clear & in-focus……..

As to propping–These engines needs to see an accurate 2700+ RPM and see it EASY..

110% for sure—- if you have the factory sized props you are GROSSLY over propped. Your vessel is 20 years HEAVIER with multiple layers of bottom paint, water absorption, gear additions, things in every compartment / corner of the boat, etc etc etc ……………

Want help? Post the pics, get your tach verified for an accurate reading at 2400 RPM at the dock in neutral, and then get me your current WOT RPM loaded as you use the boat..

Tony

[Rob Schepis]

Rob Schepis wrote:

Current conditions and history both point to overloading due to too much prop. Have you verified the rpms with a photo-tach and confirmed WOT rpm’s are 100++ over rated rpm?

????????

[Kyriakos Kostarelos]

This is a photo of the boat after 2 hours trip in rough sea at almost planning speed.

[Kyriakos Kostarelos]

Props are the official size that Tiara gives for this boat.

The port aftercooler replaced by a new one (made from a mechanic, not a cummins part)
The starboard aftercooler was in better condition and just repaired ( i don’t know exactly what was the repair)

[Rob Schepis]

Current conditions and history both point to overloading due to too much prop. Have you verified the rpms with a photo-tach and confirmed WOT rpm’s are 100++ over rated rpm?

What does “repair” of the aftercooler mean?

Post the pics that Mike requested, be sure to include your turbos and exhaust,

[Mike Mason]

Pics pics and more pics. Let’s see the set up and then the guru’s will jump in. Need more info.

[Author]

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