Engine wont pass 1320 rpm

[jeff panton]

Hello,

I have a pair of Cummins 6CTA 480 in a 2005 Rampage 38 express. I have never had any issues with them and they run great other than some white smoke at idle. Recently when trying to plane I noticed the starboard engine would not pass 1320rpm whilst the port engine would. Whilst sitting at 1320 rpm I am getting black smoke but the engine just wont go up. I have done the following:

Changed all fuel filters
Checked running gear and bottom to be clean
Checked props for damage, none seen
Removed air cleaner and tried without success
Checked turbo to be spinning free

I am now a little stumped as what to do, I kept pushing the port engine and after a good while it seemed to carry up the starboard engine in RPM and when both were at 2000 I checked the boost and engine with issue was about 3 psi off the other so don’t think boost is an issue. To get the port engine to carry up the rpm on the starboard is quite difficult and takes quite a few trys and time.

Any advice would be appreciated.

Topic

[jeff panton]

Tony,

Not everyone is versed on the “aftercooler maintenance” and I was ignorant to the fact, now that I know I am trying to correct the problem and came here after doing internet searches! So for the past 20+ years I’ve been enjoying my life without the worry of aftercoolers. I didn’t bother to post the pics of the engines as the issue was found and I didn’t think it was still necessary. I have now attached the pics as you have asked.

Jeff

[Tony Athens]

Jeff,

You are kidding me right as to asking if what I see can be re-used…………….Where have you been for the last 20 ++ yrs as to reading anything about aftercooler maintenance on SWAC engines???..

Right now, your engine ( the one that could not make RPM) has a measurable amount of seawater in the engine oil……..Your plans about that are ????

Do you know the term “Marine Age” ?

You need (2) new complete aftercoolers and you need to start understanding about proper maintenance for them and all the rest of the seawater components…………………………..The seawater circuit is the “life blood” of your engine and from the little I see, it has been 100% neglected for how long ?.

Are you planning to post pictures of the rest of the engines ?

We are really here to help you, but need you to help us help you.. Take a deep breath, post some good pics of all and let us try together to control any more damage and get you back up and running quickly, safely and with the least possible expense..

Tony

[jeff panton]

Ok I have removed both aftercoolers and taken them apart. Attached are pics of the inside of housing before any cleaning on the port one that was not cracked. My question is can this housing be used back even though the coating to the inside walls that touch the inner core has corroded away?

[Rob Schepis]

Well you were certainly making boost at one time indicated by that air intake paint burn. I would investigate your propping as well as the “nut behind the wheel”.

I thought the days of aftercoolers going to that extreme were pretty much a thing of the past with all that’s been posted and preached over the last decade or so…

https://www.sbmar.com/articles/aftercooler-disasters/

[Mike Mason]

LOM

Lack of Maintenance

[jeff panton]

What would have caused this?

[jeff panton]

Thanks everyone, whilst taking the pics I decided to swap around aftercoolers and thats when we found the aftercooler housing was cracked.

[Tony Athens]

Jeff,

1)———–When was the last time your aftercoolers were removed from the engines and serviced on the bench per my protocol?

2)——– Let me “see” good pictures of your engines as installed in the boat–All angles, all perspectives and all must be clear & in-focus.

3)——- Serial numbers and total engine hours?

4)———–Pictures of displays and or instruments

Tony

[Fireisland1]

sounds like low air flow. Clogged cooler?

[Rob Schepis]

Need pics of exhaust setup coming off the turbo. Have you pulled the exhaust off to inspect the turbo outlet?

[Author]

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