1972 65 hp seems like low power

[UncleBuck81]

I finally got my boat on the water. It idled a little rough at first but now it is driveable. The problem is, even with the lever all the way foward it seems like it should have more power. I have a 15' alum boat that weighs prob less than 3 hundred pounds before the motor. I can only go about 15-18 mph. It seems like it should go faster. Any ideas??? Thanks

 

[davidf5252]

Re: 1972 65 hp seems like low power

umm with that size boat and motor you should be going 40+ mph... i have a 30hp on a 14 ft and she runs 25+

Clean the carbs? check the plugs?

 

[UncleBuck81]

Re: 1972 65 hp seems like low power

Oh yeah, I forgot to mention what I did as I didn't know the history too well. I rebuilt the carbs, replaced the rectifier, t-stat, impeller, and fuel lines. I also did the head gasket since I had the water jacket off.

 

[jtexas]

Re: 1972 65 hp seems like low power

then I guess you've got even compression on all cylinders and spark that jumps a 7/16" gap?

set the timing, adjusted the slow speed needle valves, and link & sync per the manual?

choke plates & throttle valves all fully open at WOT?

What did you do to correct the rough idle?

What do your spark plugs look like after idling? Wet? Dry? Fouled? Any difference in appearance between the 3? Are they champions?

Have a tachometer? Whats your WOT RPMs? Idle RPMs, in neutral and in gear?

 

[UncleBuck81]

Re: 1972 65 hp seems like low power

Yes the throttle/choke plates are WOT matching the throttle lever. To fix the rough idle I gave the slow speed needles about an 1/8th of a turn in. Haven't checked the plugs yet. They are new, only that one day on the lake with them. They are NGK's. Thanks for the tip, I'll check them out.