Sooting up

[Latestarter1]

Thanks guys for your most helpful replies, I knew Paul's would be a bit more in depth one lol I know about the poor exhaust risers that were fitted, not sure if mine are or not, however they are SS ones and if I am right in thinking it was the cast ones that gave the problems, the water inlet pipe does seem to sit right on the top of the riser which could let water back towards the turbo once the engine is initially switched off.

I don't have exhaust temp gauges but I do have over heat exhaust alarms, they have never sounded.

I do know about the inter coolers blocking and the tel tale sign of burnt paint, I am happy to report that neither of mine have burnt paint and still look like brand new but I didn't know that the raw water was split to divide between the inter cooler and the heat exchangers.

Where can I get a turbo boost gauge from and any ideas of the pressure they should be running at? Can you they be tested off load or do they need to be on load

The one engine definitely makes 2800 with ease, the other has only achieved 2400,this happened in the boats first year after that engine had a new prop fitted, Caterpillar did tests on both engines and could not find any reason for it to do it, so it was left as it was, it was suspected that the prop was a slightly different pitch to the other one, I do have the original prop so I might fit it next time it's out of the water, but it is the whole of the transom that gets covered in soot so it's both engines that cause it.

mrs oaf just commented that after our first trips out she remembers me saying how pleased I was that the transome stayed clean, with my last boat P35 the transome used to soot up, (TAMD41B from memory) and I never really pushed that along, so am I cruising to slow
I do think that as others have said, they need a bloody good *******ing

PS Paul the boat is pretty much always fully loaded with gear and tanks and now she only makes about 27 knots flat out, when I bought the boat on trial it did make 30 but only just

Question answered!

The engine only making 2,400 rpm is heavily overloaded and is making your soot. Luckily you mentioned this before giving motor the beans. Failing to make WOT by such a large margin is placing a huge load on the engine. Guys from Finning needed shooting, the CAT ET diagnostic tool would have been showing 100% engine load before motor had even spooled up to 2,400 rpm.........Complete clowns, together with the people who made such a hash of the prop, all as much use as a one legged man at ass kicking party.

Get your original prop spec for your vessel which would have originally been approved by Finning and insist the replacement prop has pitch graunched back to this spec.

Moving on as I said earlier EGT gauges are common in the U.S where boaters are very much performance aware. Nothing to do with your exhaust temperature alarms.

Have posted before but ISSPRO Turbocators are a neat piece of kit.

 

[OAF]

Question answered!

The engine only making 2,400 rpm is heavily overloaded and is making your soot. Luckily you mentioned this before giving motor the beans. Failing to make WOT by such a large margin is placing a huge load on the engine. Guys from Finning needed shooting, the CAT ET diagnostic tool would have been showing 100% engine load before motor had even spooled up to 2,400 rpm.........Complete clowns, together with the people who made such a hash of the prop, all as much use as a one legged man at ass kicking party.

Get your original prop spec for your vessel which would have originally been approved by Finning and insist the replacement prop has pitch graunched back to this spec.

Moving on as I said earlier EGT gauges are common in the U.S where boaters are very much performance aware. Nothing to do with your exhaust temperature alarms.

Have posted before but ISSPRO Turbocators are a neat piece of kit.

Fortunately I still have the original prop which appears to be in good condition so I will be fitting it on the boats next lift, when I bought the boat I was told by the owner that cat had been on sea trial when the engine wouldn't reach 2800 rpm and they had used their diagnostics on the engine and concluded that it was not overloaded, I have seen many engines overloaded because the prop is too big, this engine does not appear to smoke at WOT and the shooting appears evenly spread across the back of the boat from both engines it never used to happen when I first had the boat, it just seems to have steadily got worse, I will be giving the engines a thorough service next as they are due, but fitting EGTs might be a good idea as well.

 

[Latestarter1]

Fortunately I still have the original prop which appears to be in good condition so I will be fitting it on the boats next lift, when I bought the boat I was told by the owner that cat had been on sea trial when the engine wouldn't reach 2800 rpm and they had used their diagnostics on the engine and concluded that it was not overloaded, I have seen many engines overloaded because the prop is too big, this engine does not appear to smoke at WOT and the shooting appears evenly spread across the back of the boat from both engines it never used to happen when I first had the boat, it just seems to have steadily got worse, I will be giving the engines a thorough service next as they are due, but fitting EGTs might be a good idea as well.

Going back to propellers move boats not engines, if motor not pulling rated then it has to be overloaded as prop is calling for more power than engine can deliver. Governor is asking for the fuel for a higher rpm setting however insufficient boost to produce complete combustion, remember diesel engines work on excess air. the other engine is struggling even though making WOT as it is being held back by your overpropped engine. Service guys can pull a histogram if they want to plotting boost curve against EGT.

Used to have service engineers reporting to me, they soon learned, the phrase meets spec was met with 'give me the numbers' I want data NOT words.

Stuggle to understand why you think with one engine not making rated speed you do not accept engine is overloaded. If both motors passed high idle test answer is obvious, I expect you have seen mechanical engines with linear timing tables overloaded, your engine has a 3D timing table therefore has more levers to pull however still cannot overcome the physics.

Have a Cat installation manual somewhere, think they worked on 85% max load with clean bottom for a new install.

 

[OAF]

Yep I do believe 85% is correct and I also value your input and I reckon that you are correct about the overloading, this has happened since the prop change so we have to look at that first, when she is lifted next year I will be comparing props and also swapping back to the original one,melts hope that cures it.

Thanks gain for your input, if I remember correctly you helped out a couple of years ago when I asked a few questions about cat engined boats, cheers