Re: 1978 35 hp Johnson performance question: guesstimate is fine
My best guesstimate:
The larger motor, combined with the larger prop(pushin more water), should allow you to push the same amount of weight at the same speed, but use less throttle. Even though that motor uses more fuel, you shouldn't have to buy any more or less fuel....IMHO.
Also, I think the points style ignition systems went away in '76.
Scanman, thank you very much for your insight. I agree with you. My desire to upgrade drew "oh, my goodnesses" from a few buddies who believed fuel would increase dramatically. I disagreed along the same line of reasoning as you. Further, the difference in weights between the two isn't too much: about 74 pounds versus 120 pounds. The bracket is rated for 160 pounds so I'm not overly concerned in that regard either. My gut feeling was unless the larger motor is asked to produce it's greater horsepower, which is a function of adding fuel into it's potential, and as long as the forward speed is satisfactory (or equivalent to the 15 hp optimally speaking), then the additional consumption, if very much from the 35 hp, would be somewhat negligible -- perhaps in the 10-15% range. I wanted another objective opinion and I thank you. The true test is compare them in the real world, which I will. And, if memory serves me correctly, the 15 hp under the described conditions consumes no more than about half to three-quarters of a gallon per hour. Also, thanks for the help on the electronic ignition question. I, too, thought that was pre-1978 and tomorrow I'll call a parts department and ask about a replacement coil/electronic ignition component and let them tell me it's price, or that it ain't got one. My Best Regards, Jezebel.
