3.0L Mercruiser - No Power Under Load

[‘89SeaRay160]

Hello all,
I purchased a 1989 Sea Ray 160 for the summer. It is in decent shape. The motor runs great on muffs, revs out just fine. However, as soon as it is under load it loses power. I’ve never gotten it to rev past 3.5k rpm on the water. My top speed is only 25 mph. I know I should be getting more out of this 130 hp 3.0L. I’ve worked on cars so I’m decently mechanically inclined. No matter what I’ve tried on this boat, I cannot get it to run any better under load. Carb has been replaced, has good even compression, better fuel, new fuel filter, plugs wires, etc. I just don’t have the experience with boats. Is there something I could be missing here? Open to any advice, this thing is starting to drive me crazy.
Thanks!

 

[Kola16]

So it revs in the water in neutral past 3500 RPMs correct? I wouldn't rev it past 2000 RPMs on a hose unless you have great water flow. What pitch prop do you have, how many blades, and what material is your prop?

 

[Scott Danforth]

Hello all,
I purchased a 1989 Sea Ray 160 for the summer. It is in decent shape. The motor runs great on muffs, revs out just fine. However, as soon as it is under load it loses power. I’ve never gotten it to rev past 3.5k rpm on the water. My top speed is only 25 mph. I know I should be getting more out of this 130 hp 3.0L. I’ve worked on cars so I’m decently mechanically inclined. No matter what I’ve tried on this boat, I cannot get it to run any better under load. Carb has been replaced, has good even compression, better fuel, new fuel filter, plugs wires, etc. I just don’t have the experience with boats. Is there something I could be missing here? Open to any advice, this thing is starting to drive me crazy.
Thanks!

why did you replace the carb. hopefully you didnt buy one of the amazon special carbs.

did you service the points? what was the dwell before you set timing?

 

[Scott06]

Would check if the ignition is advancing and more on what led you to replace the carb.