VT903M overheating

[Bonnie cassara]

Have CG 41 UTB with Cummins VT 903M engines

Starboard engine overheats over 12mph

Notice half flow from exhaust

Initially slow to flow, then stops flowing for seconds and eventually continues half flow. Engine runs normal temp under 12 mph.

Checked a trainers (ok)

Checked engine cooler (clean) 

All hoses seem ok

Installed new impeller

What else could be the problem ?

Topic

[Clark Leighs]

I have added my tome about overheating.   .   THere is a lot more to these systems than you have covered.   Read it through and ask questions as they arise.

 

 

[Bonnie cassara]

Thanks for your quick reply Tony

The boat is in service with the USCG Auxiliary .

The engine was installed new about 5 years ago so the pump is not that old.

I punched the engine cooler tubes with a flat metal wire (electricians snake) , flushed it with water and installed a new transmission cooler. We have been fortunate to receive all remaining CG inventory for this series boat so  I will replace the pump next to be sure it is working properly.

Thanks again

Vinnie

 

 

[Tony Athens]

Of course you know your engines and the “Innards  of your seawater pump” are over 40+++ years old..

From your symptoms, I’d say the inside of the pump housing, the cam, back plate, and inner wear plate ( all of them or a combo) are way out of tolerance…..  JUST replacing the impeller will not fix that.

Curious, how did your clean & inspect all of the saltwater small tubes in  the heat-x and transmission oil coolers?

[Author]

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