I recently finished a new powerhead install on my 1997 merc 250EFI the motor seems to run fine however it seems to be lacking power.
I have twins so here is my comparison; with both motors in gear & at idle I go full throttle on one motor & on older power head, motor accelerates to about 2200 rpm and hits powerband and builds rpm from there, give a little time and can get on plane. on new powerhead go to full throttle(other motor in gear at idle) motor turns up 2000rpm and no more rpm. no chance of reaching plane(which was obtainable on old powerhead) bring both motors to 1500rpm, go full throttle on new powerhead and new powerhead will hit powerband @ aprox 2500 and build rpm can get on plane.
- I fired injectors when motor was disassembled and they all fired and spray patterns were consistant
- timing checked and advancing correctly
- throtle plates opening fully
- all cylinders firing under load(connected timing light to each coil while tied to dock at WOT)
- fuel pressure and flow check out OK
- low pressure pump swapped ouy-no change
- EFI and ignition computers swapped from engine to engine with no change
- spark plugs swapped from engine to engine-no change
- compression checks OK in all cyl
- reed valves inspected visually when motor was apart and one set replaced(this was the cyl that had previously failed on old powerhead, debris damaged cage)
- all fuel filters replaced
- squeze primer bulb while under load and no change
- swapped air temp sensor from motor to motor no change
When running both motors together the problem is not severly noticeable until WOT and new powerhead is about 300rpm short. I am afraid to push the boat as I do not want to cook the new power head (I am worried of a lean condition)
it seems as though I am lacking a little on the powerband. Any one have any suggestions on this one I am getting stumped.
I have twins so here is my comparison; with both motors in gear & at idle I go full throttle on one motor & on older power head, motor accelerates to about 2200 rpm and hits powerband and builds rpm from there, give a little time and can get on plane. on new powerhead go to full throttle(other motor in gear at idle) motor turns up 2000rpm and no more rpm. no chance of reaching plane(which was obtainable on old powerhead) bring both motors to 1500rpm, go full throttle on new powerhead and new powerhead will hit powerband @ aprox 2500 and build rpm can get on plane.
- I fired injectors when motor was disassembled and they all fired and spray patterns were consistant
- timing checked and advancing correctly
- throtle plates opening fully
- all cylinders firing under load(connected timing light to each coil while tied to dock at WOT)
- fuel pressure and flow check out OK
- low pressure pump swapped ouy-no change
- EFI and ignition computers swapped from engine to engine with no change
- spark plugs swapped from engine to engine-no change
- compression checks OK in all cyl
- reed valves inspected visually when motor was apart and one set replaced(this was the cyl that had previously failed on old powerhead, debris damaged cage)
- all fuel filters replaced
- squeze primer bulb while under load and no change
- swapped air temp sensor from motor to motor no change
When running both motors together the problem is not severly noticeable until WOT and new powerhead is about 300rpm short. I am afraid to push the boat as I do not want to cook the new power head (I am worried of a lean condition)
it seems as though I am lacking a little on the powerband. Any one have any suggestions on this one I am getting stumped.
