Loss of power with cold diesel

CurrentSea

CurrentSea

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Ok, not related to my water issue because I had this issue before that but this season when I go out and boat is cold I notice I have no power getting up on plane. Feels like something is not engaging. Eventually I do get up on plane and boat runs with full power.

Once boat is warmed up and I try to go on plane it gets up fast. So it's only the first hole shot and only when cold.

Is this somehow related to the turbo or aftercooler?

Another symptom is boat is running hot. I usually cruise at 185 degrees but lately its 196.

Thanks.
 
Not sure what your asking.
Normally it runs at 185 and never goes higher.
Even and wot it stays at 185 normally or it did last time I had raw water system rebuilt.
 
Yeah. It’s besn running at 196 and up.
More one motor than the other.
Holds those temps even at cruise now.
Never used to.
 
When was the last time you boiled out the heat exchangers?
 
Sounds like it could be clogged aftercooler, do you have pyrometers on boat what’s exhaust temps?
 
Usually when I start running warm, it is the impeller. You need to start at the intake and check all the way through.
 
Is one engine weaker? Won't reach proper rpm?
 
Both motors always sync so no notice in lack of performance.

I changed impellers, its not them though water pumps could be scored I was told which would lessen flow.

It only goes high over 3000 RPM, so its a high speed overheat on a diesel.

I was reading that turbos don't work well when its hot out, it was 90 degrees and water was very warm.

System was boiled out about 5 years ago.
 
I think I'd take a look at the exchangers. Is there a cover you can remove so as to examine them? In Florida, Bahamas, salt water obviously, I had to boil ours out every couple of years. Otherwise they ran a little hot when on plane. I boiled them out prior to selling and the boat ran at 175 for several hours WOT during the survey.

Our engines never warmed up until we put them to work. Merely idling along didn't push them enough.

When I boiled them out, I disconnected the hoses from the shower head of the turbo and raw water strainer. Remove impeller and replace the cover. Attach hoses with a small bilge pump in a bucket and run the mixture through the whole system. This way all of the oil coolers, intercooler, and exchanger get the treatment. The system should be flushed prior to the boiling with fresh water and drained to get the mix right.
 
We need you to start over and give specific details on synptoms of each engine,
 
quote:
Originally posted by pdecat

We need you to start over and give specific details on synptoms of each engine,

Click to expand...


Yes - very important to get exact details. Can you currently get to full rated RPM + about 3-5%?Do you have EGT gages? Do you have boost gages?
 
quote:
Originally posted by pdecat

We need you to start over and give specific details on synptoms of each engine,

Click to expand...


Yes - very important to get exact details. Can you currently get to full rated RPM + about 3-5%?Do you have EGT gages? Do you have boost gages?
 
First thing to check would be for debris at the heat exchanger inlet, or whichever cooler is first, like impeller debris, sea grass etc Also if you have anything between the strainers and the water pump check for debris there too. For instance Some engines have the fuel cooler on the suction side of the pump

as to the lack of power when cold, define cold... personally I don't get on plane till the engines are close to operating temp. Could there be a safety feature in the software to limit power until warm? For instance, with large Cats, the engines are overfueled when under 145/150 degrees. I ve never tried getting on plane below that but I wouldn't be surprised if they didn't deliver full power
 
Any signs of abnormal black smoke in exhaust on that 1st attempt to plane?
 
Underwater exhaust on the pods, comes out back.
Spoke to mechanic, he says one turbo is getting hung up.
 
I thought about a sticky turbo but them you should see smoke. Easy enough to spin the turbo cold to see.

If you can reach proper RPM then turbo is coming up to speed. Do you have power meters? You still didn't say if both were running hot.
 
Just be very careful if you try to spin the turbo by hand. No axial/radial pressure should be applied.
 
So watched turbo psi this weekend. When cold and I went to go on plane, port had 5 psi and starboard 21 psi.
But then port shot up to 21 and boat went right on plane.
So it looks like port motor turbo is hanging, but again its just when cold after that it works fine.

The temp issue is probably unrelated and more around the impellers or grass.
I am going to use overtempmarine.com to flush both motors.
I have hard good things about them.
Yeah, I know easy job but I am going to watch him and maybe next time I will try myself.
He flushes both motors with barnacle buster, genny, AC units and replaces all zincs and impellers.
Will report back results on that.
 
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