gogittum
Well-known member
I'm going to be shopping soon for a spare prop for my old Johnson 15 hp and would like to buy the best choice. If it's over or under propped now, the new prop will become #1 and the present prop will be the spare. I do realize it's only a 15 hp, but proper equipment is still important.
I'll be running a lot in the Crystal River to Cedar Key areas which are notorious for very shallow rocky flats. A spare prop will almost certainly be a necessity.
With that in mind, I recently bought a cheap digital tach that has a pickup that wraps around a spark plug wire and counts impulses.
It does work, sorta, but rpm readings jump around a lot and it cuts out frequently with no reading at all for just a blink, then comes back on. I've got 5 wraps around plug lead and wrapped them tightly with electrical tape to give the best possible contact, but no joy.
Actually, I think the present prop is close enuf to "right," since motor sounds good at full throttle, not lugging or screaming, and pushes a basic, open 16 ft Starcraft tin boat to a 20.5 mph GPS reading. Still.....?? Also, in not too distant future I'll be putting a bigger motor on it - 25 to 35 hp and propping will be even more important.
Thoughts or ideas would be welcome. Thanks.
I'll be running a lot in the Crystal River to Cedar Key areas which are notorious for very shallow rocky flats. A spare prop will almost certainly be a necessity.
With that in mind, I recently bought a cheap digital tach that has a pickup that wraps around a spark plug wire and counts impulses.
It does work, sorta, but rpm readings jump around a lot and it cuts out frequently with no reading at all for just a blink, then comes back on. I've got 5 wraps around plug lead and wrapped them tightly with electrical tape to give the best possible contact, but no joy.
Actually, I think the present prop is close enuf to "right," since motor sounds good at full throttle, not lugging or screaming, and pushes a basic, open 16 ft Starcraft tin boat to a 20.5 mph GPS reading. Still.....?? Also, in not too distant future I'll be putting a bigger motor on it - 25 to 35 hp and propping will be even more important.
Thoughts or ideas would be welcome. Thanks.