what pitch for my old boat? please help

[mikesatvsalvage]

ok i have a 1983 galaxy 2.0 120hp inboard mercruiser outdrive the prop i have on it now has no stamped numbers and it takes off good planes out well but after 3500 rpm it have half my throttle left and it will not go any faster full throttle then half throttle hope someone understnds what im saying and can help. my motor runs good the carburetor is clean points are new and set correctly and spark plugs are new.

[L&M]

length of boat for aprx. weight & total wide open throttle rpm's?

[mikesatvsalvage]

boat is 16 foot long maybe 7 foot wide in rear wot my rpm is 4000 but it will run the same speed at 2500 rpm

[L&M]

It sounds like the prop that's on it now is either cavitating for some reason or the hub is partly spun out. 120hp m/c 17' glass should be some where in the range between 15 & 17p prop as a rule if it's the original ratio drive. It should pull thru the rpm range and top out at about 4300 rpm at wot, cruise between 32 & 3400.

[ray koziatek]

yes to the cavation thing ,is the prop all pitted on the backside near the hub ? it could be spun like hank said too, but its hard to imagine that you would not notice irrugular rpms under power getting on plane and if it was slipping that bad ...cavation actually causes heat at the prop (hard to belive) and causes the pitting bottom line is if rpms are going faster so should the boat ,also use your gps for speed as some (most)water speedometers have issues as they get up in age (like us)

[mikesatvsalvage]

i took this boat trade in last month i cleaned it up it had what looked like a new prop on it not a nick scuff nothing well i pulled another boater in that broke down and it caused me to go far into docking area and i chipped it up so i get in yesterday took it off and it has no numbers once i got the paint stripped off it looks like someone sanded it alot maybe it was rebuilt from a bigger prop? anyway i have no way of knowing the size. the center looks new nothing spun

[L&M]

Mike ck your pm's & give a call.

[L&M]

Good talking to ya Mike. Good luck with the boat, hunting & the atv business down there.

Hank

[mikesatvsalvage]

yes hank thanks for the advice.. i myself only hunt wild hogs there is plenty of hunting in my area and that helps the atv salvage and repair business we have. if you need any atv parts let us know we ship daily all over the world. [email protected] 1-573-276-8228 i got me a 17 pitch on its way.