1999 Johnson 25HP - Power/Planing issue

[Tim Frank]

Re: 1999 Johnson 25HP - Power/Planing issue

if this is normal behavior for a boat that is under powered then okay...
( I've just never experienced this before... cause my boats were not under powered )

for the time being, i can't afford a bigger motor...
and this one will have to do...

1) Is the boat "stock" or have you customised it?
2) you can try stripping weight and play with distribution....get weight forward if possible.
3) Try adjusting trim one step at a time and careful;l;y observe results.

 

[Pecenje]

Re: 1999 Johnson 25HP - Power/Planing issue

the bow was leaking and i had it re-riveted...

the boat is otherwise stock, other then the addition of the bowmount trolling motor and the 2 additional batteries for the trolling motor (which were removed for the water test)

other then the 2 batteries i've removed not much else other then remove the trolling motor up front...

i need the kicker at the back...

i'll try adjusting the trim and record the results
pin 1 1000rpm __mph
2000rpm __mph
...
5400rpm __mph

pin 5 5400rpm __ mph

and will report back...

 

[Cofe]

Re: 1999 Johnson 25HP - Power/Planing issue

The pic posted is an old pic... there it had a 20 suzuki tiller and a 4.5 evinrude
now it has the 25 johnson and a 4hp 4stroke yammy on it...

How did the boat perform with the 20 Suzuki on it?
Makes me wonder if the 25 Johnson you have on it now, is a long shaft, and is just immersed to deep in the water.
Ideally the anticavitation plate above the prop, should be at water surface level at WOT.

 

[Tim Frank]

Re: 1999 Johnson 25HP - Power/Planing issue

How did the boat perform with the 20 Suzuki on it?
Makes me wonder if the 25 Johnson you have on it now, is a long shaft, and is just immersed to deep in the water.
Ideally the anticavitation plate above the prop, should be at water surface level at WOT.

Good thought. the other way would also be a possibility.
That sure looks like too deep a hull shape for a short shaft....so if you happened to repower from the 20 Suzuki to a S/S 25 HP, what might that do?

 

[Pecenje]

Re: 1999 Johnson 25HP - Power/Planing issue

the transom is a longshaft
the 20 suzuki is a short shaft
the 25 johnson is a long shaft
top speed with suzuki 6mph
top speed with johnson is 19mph