Johnson 7.5 mods

[solomon]

I've got an early 80's? I think 7.5 SeaHorse. It runs good and gives my no trouble but it won't quite get me and a buddy on plane in a 12' jon. I've tried all the trim settings and it helps a little getting some boat out of the water but not quite enough. I know if I could break over on plane it would be fine. I'm not sure what pitch the prop is but I'm pretty sure it's the original. Can you swap carbs on a 7.5 or try a different prop? Any suggestions will be good.

 

[tx1961whaler]

Re: Johnson 7.5 mods

Moving more weight into the front of the boat sometimes helps.
I don't think there is a cheap, quick fix for your motor, but post the model number anyway.
The real answer is to get a bigger motor, if the boat can handle it. If there is a capacity/HP plate on the boat, it should have the max HP the hull is rated for. A good rule of thumb is to have at least 80 percent of the max HP rating in order for the boat to perform correctly.

 

[solomon]

Re: Johnson 7.5 mods

I think the boat is rated for a 15. I've tried putting some weight in the front but the motors just not pushing hard enough. The best results are with weight in the middle and the motor trimmed up.

 

[dkonrai]

Re: Johnson 7.5 mods

how old are the coils? is the motor getting the rpms?

 

[samo_ott]

Re: Johnson 7.5 mods

Sounds like a bigger engine is needed...

 

[solomon]

Re: Johnson 7.5 mods

I'm not sure how old the coils are, but it's getting good rpms. It runs fine. Just wondering if I could give it a little "boost", being that close to getting on plane. Hate to have to buy another motor.