prop pitch

[b2krawler]

I have 17' runabout, with an 85hp Mercury Outboard, Im running a 17degree pitch, 3 blade, aluminum prop at 6000' elevation, I am having trouble getting on plane. What pitch do you reccomend, Do i also need to buy a new hub, does that come with new props?<br /><br />Do different brand props for my motor require different brand hubs or is it inter-changeable<br /><br />I used to run about 5000rpm at WOT, when lower unit was replaced, so was the prop, now I only get about 3800rpm, not sure what the orginal prop pitch was?<br /><br />Thanks

 

[Moody Blue]

Re: prop pitch

thats a big drop in rpm. Must be more too it than a change in prop pitch. The change in rpm would indicate about a 6 inch (not degrees) change in pitch would be required to bring the rpm's back up to 5000. Can't see an 85hp with an 11" pitch prop. What is the diameter of your prop now ? Have you recently moved to the higher elevation ? The carbs need to be re-jetted when running at high elevations. Have you checked for spark on all cyls ? Maybe only some are firing.

 

[Coolmaker]

Re: prop pitch

"Changed the lower unit", sounds like it could be a gear ratio change that caused the problems.....