Caterpillar engine question

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nav1

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Hi,

I was on a Fairline 41 yesterday and whilst we were out the engines would only rev to circa 2100 / 2200 max - and it topped out speed wise somewhere similar, circa 21 knots

Back on the berth both engines ran up to 2600 rpm without any issue - i believe they should be capable of revving up to 2800 - they are the 3208 Turbocharged (375hp) version - so perhaps a cable adjustment may get it to the 2800rpm, however can anyone advise why they should not rev to 2800 whilst cruising? could this be a prop issue? i appreciate the speed could be affected by a dirty hull, but should the engines still not rev to 2800 anyway?

thanks in advance
 
Dirty hull
Dirty props
Wrong props
Boat weight
Dirty air filters
Dirty pre-filters

All could stop you reaching max revs underway. Unlikely to be cable adjustment. You should reach max revs in neutral, so possibly points to fuel or air supply, but do check max rev on that engine model so you're not chasing ghosts
 
My father had the same boat and experienced the same issue a couple of year back. We had an engine-guy look at it and I believe he found a couple of issues. The one I remember is that the cylinder nozzles needed to be cleaned (and a few of them needed to be replaced). However, the engines in my fathers boat was the Volvo Tamd 61 306hp. This might be totally irrelevant in your case but I just thought I would share. Hope you find a solution!
 
And don't forget rotten turbos and stuffed aftercoolers... Run them for long like this and they will be cooked regardless of the reason... High egts from too much load and not enough revs..

Could also be overpropped if it's always been like this... Start at the fouling as it's cheap to clean and eliminate from there...

Steve
 
thanks guys, both engines were completely rebuilt and have only done 200hrs since. i think i will get an engineer to go and have a good look

Appreciate your comments

cheers
Paul
 
nav1 said:
thanks guys, both engines were completely rebuilt and have only done 200hrs since. i think i will get an engineer to go and have a good look

Appreciate your comments

cheers
Paul
Click to expand...
My late father had a pair in his boat , I rebuilt one from block up inside boat .
Great motor but very heavy for its HP.

Check the exhaust flap smoke limiter if it has one , back of turbo , I wired his open , RNLI used to take it off along with smoke limiter to injection pump .

If bottom is dirty it won’t rev like any other boat .
High idle test at quay side proves nothing as it’s not under load .
 
I have a Fairline 41 with the 435 - 3208s revs top out at about 2700 rpm giving 29.8 knots. Cruise 2200 rpm @ 24 knots, given the engines are 29 years old with 1200hrs. I am quite happy with the performance
 
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