Fishinghaoliboy

I posted previously concerning power for this motor. Have now gotten to drive this boat a 25 ft Force with Flybridge and was not impressed with speed. With a load of 6 people and 10 dive tanks the boat will not get on plane. It has been run out of fuel 2 or 3 times and I am thinking the fuel system is plugged. It is a 6 bt 5.9-m engine Ser # 45534413 produced in Jun of 97. The Turbo has the numbers on the exhaust side of 25B6C or 25B5C, the boost side has a H-2 in the casting. I would like to replace the injectors and possibly also the Turbo. The previous owner said it ran 2650 rpm's at about 25 knots. It will barely get over 2000 rpm's with a load of 3 people at this time. Can I put 370 injectors in this engine and should I also look at a change with the turbo? I am not looking for a speed boat but 15 to 20 knots with 5 to 6 people would be nice.

wv smoker

If it would run up to the governor before, you must have a developing engine problem, a dirty bottom , or maybe too much weight for your rear end ratio(prop size and pitch). I think I would fix the problem before trying to step up the power? Hope this helps............

Fishinghaoliboy

The bottom is clean prop is the same and just running the boat out of fuel 2 or 3 times is all I know has changed. The people using the boat added a fuel bulb into the fuel line to pump fuel to injectors. I believe that to be a restriction, the only other thing I have not checked yet is whether is has taken some water into an unseen space. I think it is a fuel delivery problem, but the injectors are original and the motor has 2900 hrs or so, so thought if I were going to replace them I would go to larger ones if that would help at some point. I would guess that the 2650 rpm's was the governed speed for this motor but it won't come close to that at this time.

Dufrain

maybe you could check the air filter and fuel filter,there could be algae in the tank or rust or who knows what.,I wouldnt think the injectors would be anyway near worn out,unless you jst want to change them for more power.Im pretty sure 370s are marine injectors for a 370hp engine so I would think they would work when you get it running right.

gwhammy

Pulling a boat at speed is probably like pulling a loaded trailer up a hill that never ends. You would really have to watch the exhaust temps and oil temps real close.The positive thing thou is an abundance of cool water to cool the intake temps and engine heat. You probably could push the motor up to the 370 hp range and be safe at factory ratings if the components are the same. Do you know if the cam, pistons, or any other parts are the same. I think the timing on a 370 marine is 18.5 which probably works good on a motor that runs at a constant rpm. Compression might be different to. There's alot to think about on a motor that runs at a constant load.

winner172

less pitch in your props and your engine will turn up easier and last longer.
you will lose a couple of knots unloaded but it will be alot easier on it with a load

Fishinghaoliboy

So it sounds like if I want to change injectors I can use the same 210 injectors or could possibly go to a larger size with little or no problems. The engine runs a constant 150 degrees and has plenty of cooling. My thought was to change to a larger injector if it would basically run the same with the option of pushing it a little. I believe there is a problem with fuel delivery but also thought the injectors might be suspect as there was some water in the fuel tanks etc. That is all cleared now. I will do the filter stuff again as the fellow who has been running it said it was all changed but running the tanks out could easily have plugged the filter.

signature600

I punched your engine's serial # in my computer and found that it is a CAV rotary pump engine. Is this right?

Unless this pump is VASTLY different from a Bosch rotary pump, you won't get near 370 hp without A LOT of modification.

Good luck,
Chris

Fishinghaoliboy

Injection pump looks just like the one on my truck. I don't think it is a rotary pump. All I am asking as the owner is willing to buy new injectors is what I should put it for injectors. The same 210 injectors only new or can I gain a little hp by going to a different injector. I know and will check/change fuel filters, air filter, fuel line for leaks, etc.