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89 mercury force 125 power and speed

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  • 89 mercury force 125 power and speed

    I recently bought a 1989 vip fish/ski with 125hp mercury force outboard. The only thing mechanically wrong was a tilt valve I had to rebuild. I replaced all four plug ( cus theyre cheap) and it sounds good. I have a 13*19 aluminum prop on. It gets out of the hole and planed out very fast but my top end is only about 38mph no matter what I have in the boat for weight. I am just wondering if this sounds right to you guys. I forgot the last time I took it out to watch the RPM,s at WOT. But Ill post that later. Its a pretty heavy boat but I guess I just figured it would be fastr than that since I have a 76 tri hull 16' ( VIP is 17'7") that goes almost 45 mph with a 90hp. Any suggestions or info would be appreciated. Im also wondering what other size prop I should try and what it would do I dont know much about them thanks.

  • #2
    Re: 89 mercury force 125 power and speed

    What size boat? RPM's? 38 is pretty good for a 125
    As for different props gotts know RPM's at WOT!!! J


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    • #3
      Re: 89 mercury force 125 power and speed

      Thanks for the reply, its a 17'7" fiberglass fish/ski.its pretty darn heavy. I just figured it would be a bit faster not that I need it to be. I am planning on going out today and will try to remember to watch the rpms at wot and get back to you.

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      • #4
        Re: 89 mercury force 125 power and speed

        you need the max pitch prop to put the WOT rpm in the range specified by the maker ...after that you only go faster with a bigger motor......a change of 2 in in pitch will change the revs by 400 rpm.
        Your speed sounds about right to me

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        • #5
          Re: 89 mercury force 125 power and speed

          my 19 ft bayliner does 42 mph at wot i have a 17 pitch prop on my 87 force 125 seems to me you are pretty close to where you should be again not knowing how heavy your boat is. i am suprised that it doesnt make a difference how loaded you are though. try using a gps boat gauges can be off by a fair amount.

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          • #6
            Re: 89 mercury force 125 power and speed

            forceproblem...42 mph really!?!?!

            that is awesome, on a good day when my motor runs right I get maybe 20 mph and it is the same boat with a 15" prop. In my head that is just awesome.

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            • #7
              Re: 89 mercury force 125 power and speed

              I get max 30 MPH on gps with my bayliner 19 feet and force 125 89.
              I would really like that mine goes good like that. But I think I need to set timing correct to get few more MPH

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              • #8
                Re: 89 mercury force 125 power and speed

                I get 44 MPH from a Force 125 ( 1988) on a 16ft custom bowrider, with a 19" prop. I changed to a 17" S/S, and get 42MPH at WOT. I don't like WOT though- she is 20 years old. I stick to the 30-35MPH range. Better for fuel, and the difference is getting to your fishing hole about 2 minutes before the next guy. I can live with that!
                Make sure you start with the simple things first.Ask yourself- " IS MY BATTERY CONNECTED"

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                • #9
                  Re: 89 mercury force 125 power and speed

                  Thanks for the replies guys! Its good to know that its running about where it should. I monitored last time I went out and was running about 33-34mph at 4500 rpm ( with no trim) when trimmed up i was getting about 38-40 mph at about 5000rpm. That book on my motor ( force outboards 85-125 hp) statet the optimal operating range at 4500-5500rpm. If that sounds good to everyone I wont even worry about it. The only other question I have is motor pulls me to the right. My exaust port is all the way in the opposite direction ( trust me the other way is MUCH WORSE). But still pulls. The only thing I see is the vert fin on the very bottom is slightly bent. Any ideas?

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                  • #10
                    Re: 89 mercury force 125 power and speed

                    And I thought 42 mph was just ok.
                    For what I hear I'm doing great. The only thing that improved my mph was the 17 pitch stainless prop got my wot at about 5300 rpm and a good hole shot . Other then that no extra weight.

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                    • #11
                      Re: 89 mercury force 125 power and speed

                      Ya thats actually what i was trying to find I just have not come across one yet. I was thinking that would do exactly what your describing. So if anyone knows where to find one that would work(17") or has one to sell Id like to give it a shot.

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                      • #12
                        My 89 Force 125 on my 21ft. Bayliner Arriva got 30 mph at WOT with a 15 pitch prop & 36 mph with a 19 pitch. A 17 would be perfect.

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                        • #13
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