1977 15hp johnson power problems

[swags]

Hello, i have a 14ft fiberglass boat with a 15hp johnson. The guy i bought the boat from said he had a 15hp on the boat and it would fly. So i went ahead and bought a 15hp, and it wont even get the boat on plane. I did a compression check when i bought the motor like 3 weeks ago and I got 110 on each cylinder. Can anyone tell me what i can do to fix this problem.
thanks,
Ron S.

 

[tashasdaddy]

Re: 1977 15hp johnson power problems

is it a long shaft on a short shaft transom? have you check spark? linc n sinc, is it getting to wot.

 

[tx1961whaler]

Re: 1977 15hp johnson power problems

What kind of boat? If there is a capacity/HP plate on the transom, what does it say? A 15 HP on my 13' whaler (pretty heavy..) certainly wouldn't make it fly.

 

[Patate]

Re: 1977 15hp johnson power problems

15 on my "fisherman" style 14' boat make it fly, like 39km/h, or 24 mph, not so bad

 

[Whoopbass]

Re: 1977 15hp johnson power problems

Even with a light 14' glass boat I doubt you would get much more then 20 mph out of it.
You have 5 height positions on that motor. Run it in the 3rd hole.
Find out what pitch prop you have and check here and see if its the one you should be running:
http://dansdiscountprops.com/BuyNow/propWizard.cfm

You would probably be better off selling your outboard and getting a larger motor. It's not going to cost you any more $ since 15hp are worth as much or more then a 25-35 hp motor.

 

[swags]

Re: 1977 15hp johnson power problems

The plate on the boat says it's maxed out at 20hp, so i would think 15hp would be plenty. The motor is a short shaft as well as the transom. I'll look at it to see what height position it is in and adjust acordingly. Thankyou all for your advise so far.

Ron S.

 

[crxess]

Re: 1977 15hp johnson power problems

Make it fly >is a relative statement. Dependent on one persons concept of fast.

Does the motor pull the boat up on plane in a reasonable amount of time?

Is the prop correct for hull design/load?

Have you fully serviced the motor?