johnson seahorse 25hp problems

[skog]

Last night I took the boat out for a ride.  She has sat idle for 2 years. The motor ran good but every couple of minutes it would red line and the prop would slow down.   I would get off the throttle then back on it and it would be fine for about 5 minutes and we did this the whole way out and back(2.5 miles each way)  When it ran good we topped out at 12 to 13 mph wide open when it didnt slip.  The prop pin is not sheared and the boat is a 16.5 ft. sylvan.  The boat used to do mid 20s when we put her away.  The best i can decribe it as a clutch slipping in a vechile, I dont believe there are any clutches in it though.

Thanks
skog

[hillbill]

skog, check this, some of those moters had a rubber bushing in the prop. when it went bad and started to slip it would do what your describeing. take your prop off and look at it. is there a rubber bushing between the center of the prop where the shear pin goes and the outer part? if so ill almost bet a months beer yu need a new prop. let us know what happens.

[NOLA]

You do not have to buy a new prop .
you can have a new hub put in that one
check with any prop shop and they can do it

[hillbill]

nola, good call, i had plum fergot bout gettin prop rebuilt! :shock: was 25 or 30 buks las time i had one dun.

[Flash]

Your motor has a vacuum operated RPM limiter on it and when the motor redlines, the points from the bottom cylinder are shorted out and the RPM decreases. This saves the engine from damage.