Bigshannon56
Cadet
- Joined
- Apr 26, 2016
- Messages
- 8
Ok this is a lengthy story, but im going to give as much detail as i possibly can so maybe some of you more knowedgleable fellas can give me some insight as to what my problem is. Ok in 2008 i bought a brand new yamaha 70hp 2 stroke and had it mounted on an 88 model nitro fish and ski boat. Ive ran it every summer and never had a minutes trouble out of it. She starts every single time like clock work, and runs wide open jist like it should. Gps with by myself 41 mph going up stream on the river! Has a 13.5 x 15 prop on it and with no tach guage i never actually saw the exact rpms it ran. Having owned a few outboards, i could always tell it was prelly well wound up, but not to high. Compresseion is perfect. New plugs every 2 years and lower unit oil replaced every spring. But never any carb cleaning or anything major. We took it off and mounted it on a 2006 22' suncatcher pontoon boat that the previously had a 90hp yamaha on it so the controls were all there and our motor hooked right up. I drained the gas tank. Instaled a water/ fuel seperator, and filled it with fresh gas. In my drive way with the muffs on it starts and runs just as it always has. According to tach guage its idling at 700. And revs like it should. Goes into gear and throttles up like it should. We toook it to the river and all works well. Except for when opened up all the way im only getting 2200 rpms and 12 mph according to the guage. Im not sure if the tach is exactly right but to me it sounds like its half theottle and struggling when its wide open. Im convinced its a prop issue. Any feed back is much appreciated.