Cummins 4BT 3.9M 150 Engine

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CT115

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Hello Everyone

I'm currently looking at buying a 43ft Dutch Steel motor boat with a Cummins (Vetus marinised?) 150hp 4BT 3.9-M engine.

The current owner has told me the engine details as follows:
Date of manufacture 16/08/90
Serial No 21087384
Model No 4BT3.9-M
CID 239/3.9

If anyone was able to give me any pointers about what to look for about these engines that would be greatly appreciated.

Thanks

Jeremy
 
CT115 said:
Hello Everyone

I'm currently looking at buying a 43ft Dutch Steel motor boat with a Cummins (Vetus marinised?) 150hp 4BT 3.9-M engine.

The current owner has told me the engine details as follows:
Date of manufacture 16/08/90
Serial No 21087384
Model No 4BT3.9-M
CID 239/3.9

If anyone was able to give me any pointers about what to look for about these engines that would be greatly appreciated.

Thanks

Jeremy
Click to expand...

Jeremy,

Four cylinder version of Cummins 6BT 5.9 210, all the same performance parts and a long running model. 6BT150 came out in in 1986 and can still be purchased pretty much unchanged under the Cummins ReCon program. A rough litte diamond.

In 1997 a pal of mine purchased a new 4BT 150 for a 30 ft twelve tonne crabber in Cornwall. The yard who installed the engine thought it was undersized for the job. We propped the motor 'light' and fisherman owner is sensible and only wrings the nuts out of the engine when running for home when weather threatens. I looked at the engine about three years ago and he was up to 14,000 hours. So far engine has suffered a failed gearbox lube oil cooler, fuel lift pump and has has raw water pump changed twice as body simply wore out and despite overhaul kit in the pump was not producing output. Not aware of current hours but must be well on the wrong side of 15,000 hours.

Your details are correct, Darlington built engine, one small downside pre 1991 engine with 9mm injectors, if engine is run pulling more than 80% load for long periods head can crack between injector hole and valve seat, hence change in '91' to 7mm injectors.

Use Fleetguard LF3349 lube filter for Cummins 6B. LF3349 is higher capacity than the filter specified for the 4B (cannot remember # off the top of my head as never use it!) LF 3349 comes out at less than £8/9 half the price of the correct 4B filter because 6B production volume is far higher.

Is this a keel cooled or heat excahnger motor.

Bejansailor on this forum has a pair in oil spill vessel.

Good luck.
 
Hi Latestarter

Thanks for that it's very helpful. I am pretty sure it is heat exchanger cooled.

Sounds like it should be fine for a 13ish ton steel motor boat that will predominately be doing 5/6 knots in the European inland waterways with an occasional 12 hour North Sea crossing doing 7/8 knots.

The only negative that I had heard was that there can be problems with corrosion in the Vetus water cooling system, do you know anything about this?

Many thanks
 
CT115 said:
Hi Latestarter

Thanks for that it's very helpful. I am pretty sure it is heat exchanger cooled.

Sounds like it should be fine for a 13ish ton steel motor boat that will predominately be doing 5/6 knots in the European inland waterways with an occasional 12 hour North Sea crossing doing 7/8 knots.


The only negative that I had heard was that there can be problems with corrosion in the Vetus water cooling system, do you know anything about this?

Many thanks
Click to expand...

Ah ha sounds like you have the earlier Vetus CT4 model with Vetus header tank on the side and their own Bowman clone heat exchanger below. No personal experience of this set up however can see it being prone to corrosion as it has no anodes.
 
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