Another prop question. . .

[eyewinder]

Last fall I tore up my outboard's prop and replaced it with the same prop (13.75 x 15 Merc. 3-blade aluminum). This prop is on my 115 h.p. 4-stroke Merc that powers my Ranger 690 VS (18-plus foot glass multi-species). While some would say that's not enough motor for the boat, it has performed well enough to please me and I have had no complaints.

Since this spring, though, when I installed the replacement prop, the motor accelerates to about 3000 RPM, hesitates, then continues to gain RPM, but no more speed. RPM will continue on past 5000, but speed won't exceed about 10 mph. Previous top end, with acceptable hole shot, was about 30 mph @ 5500 RPM.

I've taken it to an alleged mechanic, he took it out on the water, and he said it ran fine (I should have accompanied him). Later that day, when I resumed fishing, I had the same performance problems, and have had since.

I've resisted trying another propeller configuration, because the one I ruined worked so doggone well--but I'm kind of at wit's end.

Can anyone recommend a different prop (I'd like to stay with a 3-blade aluminum) that would get me back to where I was before I destroyed the one that worked so well last fall?

Thanks in advance,
eyewinder

[propmann]

Originally Posted by eyewinder

Last fall I tore up my outboard's prop and replaced it with the same prop (13.75 x 15 Merc. 3-blade aluminum). This prop is on my 115 h.p. 4-stroke Merc that powers my Ranger 690 VS (18-plus foot glass multi-species). While some would say that's not enough motor for the boat, it has performed well enough to please me and I have had no complaints.

Since this spring, though, when I installed the replacement prop, the motor accelerates to about 3000 RPM, hesitates, then continues to gain RPM, but no more speed. RPM will continue on past 5000, but speed won't exceed about 10 mph. Previous top end, with acceptable hole shot, was about 30 mph @ 5500 RPM.

I've taken it to an alleged mechanic, he took it out on the water, and he said it ran fine (I should have accompanied him). Later that day, when I resumed fishing, I had the same performance problems, and have had since.

I've resisted trying another propeller configuration, because the one I ruined worked so doggone well--but I'm kind of at wit's end.

Can anyone recommend a different prop (I'd like to stay with a 3-blade aluminum) that would get me back to where I was before I destroyed the one that worked so well last fall?

Thanks in advance,
eyewinder

Sounds like a bad hub, if prop has old style rubber hub on it put a mark on the prop and a mark on the hub near the nut and take it out again if it doenst line up when you get back your hub is shot. If its the never style with the plastic sleeve insert make sure you've installed the plastic sleeve.

[propmann]

Oh yah if you were happy with the 13.75 x 15 prop before stick with that on or the new quicksilver nemesis or the mercury spitfire in a 4 blade are performing very well also with better holeshot and cornering and some are even faster then the 3 blade.

[eyewinder]

Hub was suspected, but it's a new one that I purchased with the prop, and the mechanic pulled the prop and said the hub was good.

That sure would have been a quick & easy fix!

[wiredog]

Your saying that your motor turns 5000 rpms but you only go 10 mph??? You better find another Mechanic!!! No doubt you have a prop hub problem. Wiredog

[Tim_Kelly]

If the hub is OK, then I suppose it's possible that the lower unit it damaged from the initial accident and slipping under load. Would be unusual though. Hub or ventilation are the usual causes.