Thread: speed vs rpm

Spun hub would greatly increase your rpms. You may have had a power pack drop out.

The hub slipping would be my first guess. I hope you have a good prop shop locally as that is the only way I would check. If you take it to a boat shop and have them check it you WILL be told that you need a new prop. If you do not have a spare prop, this would be the time to buy one. Swap it out and if your speed comes back, send the original out to be re-hubbed.

mrdux: all 4 cylinders firing good

Clint: there's a very good prop shop in Clarksville IN right across the river, and I also have a '77 johnny 85hp that has the same prop. I was going to switch them as you suggested and give that a try. I was just wondering if anyone else had the same thoughts as I did.
thanks to both of you for input.

Get you a indelible black marker. Make a mark on back of prop and one on housing that align. Put in water and just put in gear and goose it up while on trailer until rpm comes up and really dosnt push against trailer. Shut it off pull out and check marks. Bet they won't be aligned. Hub is slipping. Any good prop shop will replace your hub. Yes those 2 props will interchange.

Originally Posted by cray

Get you a indelible black marker. Make a mark on back of prop and one on housing that align. Put in water and just put in gear and goose it up while on trailer until rpm comes up and really dosnt push against trailer. Shut it off pull out and check marks. Bet they won't be aligned. Hub is slipping. Any good prop shop will replace your hub. Yes those 2 props will interchange.

would you believe that I had a prop sales person tell me that my 2 motors don't exist?? I even gave him the serial numbers off them, he couldn't find them listed in his book. I still laugh about that. I did find them but they were listed as commercial engines
thanks for your rely cray