nissan 2 stroke 15hp no power in gear

jimmyboy82

Cadet
Joined
Jan 3, 2010
Messages
9
Hello guys I have a 1992 nissan 2 stroke 15hp that starts fine and revs up in neutral fine but in gear has very little power. We are testing the motor in a 9 foot zodiac with 2 persons onboard. We are having a hard time trouble shooting it so I thought I'd post on this forum.

Any and all help will be greatly appreciated, Thanks guys :)
 

pvanv

Admiral
Joined
Apr 20, 2008
Messages
6,500
Re: nissan 2 stroke 15hp no power in gear

What symtoms, if any, aside from insufficient thrust? What prop are you running? Sounds like possibly too steep a pitch (over propped).
 

jimmyboy82

Cadet
Joined
Jan 3, 2010
Messages
9
Re: nissan 2 stroke 15hp no power in gear

The best word I could use for full throttle is "bogged' down. It really seems to be the old original prop. In neutral it revs like a dirt bike engine but in gear very low revs just enough power to go about as fast as allowed in a harbor. very very slow. Its using new gas.
 

Sea Rider

Supreme Mariner
Joined
Sep 20, 2008
Messages
12,345
Re: nissan 2 stroke 15hp no power in gear

The best word I could use for full throttle is "bogged' down. It really seems to be the old original prop. In neutral it revs like a dirt bike engine but in gear very low revs just enough power to go about as fast as allowed in a harbor. very very slow. Its using new gas.

Check propeller hub, maybe slipping on shaft, check gear oil in lower unit, if completely dry, pinions have wored off. Is it same problem in reverse gear ?

Happy Boating
 

jimmyboy82

Cadet
Joined
Jan 3, 2010
Messages
9
Re: nissan 2 stroke 15hp no power in gear

In reverseits the same. The lower unit is fine. Under full throttle in gear it deosint sound good. When I first tryed the motor it had a few very short moments where it would power up and I would actually let off the shrottle as I should after all its a 15hp in a 9' zodiac but after that it never picked up power again. My friend loaned me his 15 hp 2 stroke suzuki motor and it performs the same (very very little power) and his motor is as old as mine so I'm wondering if its something common that happens to 2 strokes that are 20 years old. My motor starts one pull and revs up high in neutral if it reved half that high in gear I would be skipping accross the water . I hope we can figure this one out we have been tinkering with it but no success. Thank you very much for the help :)
 

pvanv

Admiral
Joined
Apr 20, 2008
Messages
6,500
Re: nissan 2 stroke 15hp no power in gear

In Fresh Water (around here on the Great Lakes), 20-year-old OB's are very common, and they don't suffer that kind of degradation in power from age alone. Sounds again like a propping issue of one sort or another.
 
Top