Re: 15HP JOHNSON-HOW TO MAKE IT FASTER

Posted by Ed Mc. (67.250.176.144) on January 10, 2004 at 10:01:01:

In Reply to: 15HP JOHNSON-HOW TO MAKE IT FASTER posted by BEN on January 09, 2004 at 13:42:25:

If it were possible, you wouldn't like the power band.

You'd have to grind out the intake and exhaust ports, to get more fuel charge in. While giving more top end power, it would ruin your motor's low speed characteristics. Also you could make exhaust mods which would make your motor very loud and obnoxious.

If you can find a stainless prop for your motor, it might make a slight improvement. But that's a pretty spendy addition in itself.

Making sure the motor is set up properly on the boat is another way of assuring the best performance out of what' you've got. If the motor is too far down in the water it'll cause extra drag which will slow you down. If the bottom of your boat is not straight, it'll reduce hull speed. Weight distribution on a small boat is important too, you might try moving the fuel tank to the front if possible.

Planing aids such as the Doel-Fin will greatly improve a small motor's ability to get a boat up on plane.

If it's a weight concern, the older (70's or so) Johnson/Evinrudes had a 20HP and 25HP which were based on the old 18HP block and are much lighter than the next generation motor which was available in 20, 25, 35 HP versions.

One of "Light" 25's would pack a lot of punch but be no heavier than an 18.

Of course, the later powerheads are much stouter but the old ones are still good motors and very serviceable.

HTH............ed