Yanmar 4lha-stp, lack of power

[Ellison s]

I’ll keep it short and to the point. I did a motor swap from a Volvo d3 to a yanmar 4lha-stp. I’m running a Volvo dps-m Outdrive with 195 gearing boat is 21’ and about 5500 loaded. problems- No power going up the trailer(rpm no higher then 1600). Lope between 900-1100 rpm, boat only gets 24knts wide open at 3500 plus. Put bigger props and lope is at idle(real bad) and 1k rpm going up trailer.  motor info. Injector pump rebuilt, injectors re-set, heat exchanger cleaned,  and after cooler cleaned. Turbo spins freely, clearance less then 10 thousands on both sides, props Volvo i6(small). smoke only little bit at 2500, wide open rpm around 3500. Will check later with certified tach Later.  My last motor pulled 22kts at WOT rated at 160hp. I don’t believe I’m getting the full potential from this motor. Injector timing off? Can that cause lack of power? 

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[Tony Athens]

What the past history of the motor?  Didn’t you run it before the install?

 

Why did it need a injection pump rebuild?.. Certified shop?  The loping could be a bumper spring issue ..

 

Get a 0-30 PSI accurate boost gauge on the engine, and get your tach accuracy verified at a steady 3000 RPM in neutral

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