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1993 40hp Classic Mercury

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Willie#34

New member
Just bought my 40 hp Classic.The man who had it said it has been setting for about 1 year.He said before he parked it he was getting 41 mph on a 16 ft War Eagle.I put it on my 15 ft and I can only get 26 mph with a good set up.Motor sounds as if I'm not turning any rpm.Has slight sound change at full throttle.Cleaned carbs,changed fuel lines and spark plugs.Any ideas or suggestions?
 
Get a Tiny Tach or something similar and see what your rpm are..what kind of boat are you running?...what pitch prop?
 
Did he get that speed with the speedometer or gps. My 16' starcraft with a hull weight of 650# and a 70 Hp Evinrude runs 38 with a light load. The same boat with a 50 Yamaha 3 cyl ran between 8and 10 MPH slower. I think the speed for your boat sounds right maybe a couple more mph. I don't know about getting to 40mph 30 might be in reach.
 
I ran a couple 50 mercs in the late 60's and early 70's..both were on 80 gauge 15 foot john boats with a wheel etc..30 is a ballpark wot with a 15 inch prop....maybe 32 under perfect conditions...if the prior owner of this motor actually exceeded that he was over revving the motor with a wrong prop..
 
Don' get hung up on speed get the tach and do your set-up correctly. The only true way to get more speed is to put the max HP your boat. If you already have the max HP get a bigger boat and motor. Sorry my last post cut off on me.
 
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