9.5 Johnson/Evinrude speeds

[dregsfan]

I took my 12' Gregor with the 1965 Evinrude 9.5 out for the first time yesterday. The 9.5 moved the boat pretty well. Judging from what my Sea Ray does (30-35MPH), the 9.5 seemed like 15-20MPH. I was wondering what speeds other 9.5 users have with similar hulls.

 

[ezeke]

Re: 9.5 Johnson/Evinrude speeds

The fastest theoretical speed would be with the highest stock propeller pitch (9) at maximum 5000 RPM and no slip - that would be 24 MPH.

Semi V 12' boats with much of a load are hard to get on plane with a 9 pitch prop using a 9.5. I use a 6.5 or even a 5 pitch on mine which puts you at around 17 MPH or 13 MPH maximum theoretical speed, respectively.

Use 1.769 for gear ratio (23/13): http://go-fast.com/Prop_Slip_Calculator.htm

 

[kbait]

Re: 9.5 Johnson/Evinrude speeds

Nice running motors.. but if you want power, a late 50's-early '60s 10hp sportwin is gonna mash any 9.5. They're way more like a 7.5 than a 10. But they sure run sweet.

 

[dregsfan]

Re: 9.5 Johnson/Evinrude speeds

The 9.5 is just fine. Especially when I only paid $40 for it at a garage sale with two extra props!

My prop is OMC P/N 387334 which is a 8x7.

 

[ezeke]

Re: 9.5 Johnson/Evinrude speeds

That's a good propeller for your boat. It should put you around 18 MPH on plane if you can reach 5,000 RPM, but a little slow coming out of the hole.

387334 was a 6HP prop like the 5 pitch prop that I use #386587.

 

[dregsfan]

Re: 9.5 Johnson/Evinrude speeds

Thanks for the info. No idea what the WOT RPM is. I've got a portable Tiny Tach on my Sea Ray's 3-cylinder MercJet, but I don't think it will work on a twin.

 

[ezeke]

Re: 9.5 Johnson/Evinrude speeds

Thanks for the info. No idea what the WOT RPM is. I've got a portable Tiny Tach on my Sea Ray's 3-cylinder MercJet, but I don't think it will work on a twin.

TinyTac will work, but call them first to get the correct one.

 

[dregsfan]

Re: 9.5 Johnson/Evinrude speeds

I like the pull handle. Mucho better than the tiny stock unit. I have an old rubber toggle handle from a sea kayak laying around. It would be any easy swap. Thanks for the idea!

 

[Kobie]

Re: 9.5 Johnson/Evinrude speeds

My friends 1968 9.5 Evinrude on a 14ft flat bottom aluminum runs 21 on the gps. The boat weighs about 130, him about 140, and 3 gallons of gas.

Now if you want some speed, get a 80's model 9.9-15hp Evinrude. Here's a video I just took of mine. Runs 29.6 gps with a 9.5x10 prop. Im getting a 9.5x13 made to push past the thirty mark.

http://www.youtube.com/watch?v=cNe87kDEF1U

 

[ezeke]

Re: 9.5 Johnson/Evinrude speeds

My friends 1968 9.5 Evinrude on a 14ft flat bottom aluminum runs 21 on the gps. The boat weighs about 130, him about 140, and 3 gallons of gas.

Now if you want some speed, get a 80's model 9.9-15hp Evinrude. Here's a video I just took of mine. Runs 29.6 gps with a 9.5x10 prop. Im getting a 9.5x13 made to push past the thirty mark.

http://www.youtube.com/watch?v=cNe87kDEF1U

29.6 mph is not theoretically possible with a 10 pitch propeller unless you are over the rated top RPM (6,500) for the 15HP. You would have to be turning over 7,500 RPM to reach that speed.

 

[Kobie]

Re: 9.5 Johnson/Evinrude speeds

29.6 mph is not theoretically possible with a 10 pitch propeller unless you are over the rated top RPM (6,500) for the 15HP. You would have to be turning over 7,500 RPM to reach that speed.

How much weight did you put into the equation? My boat weighs 100, me 115, had 2 gallons of gas, and just the required safety gear. My rpms are at 6000.

 

[ezeke]

Re: 9.5 Johnson/Evinrude speeds

No weight, no slip, that's absolute theoretical maximum speed unless you are flying with a 30 mph tail wind.

Do the math. http://go-fast.com/Prop_Slip_Calculator.htm

 

[1946Zephyr]

Re: 9.5 Johnson/Evinrude speeds

The 9.5 is just fine. Especially when I only paid $40 for it at a garage sale with two extra props!

My prop is OMC P/N 387334 which is a 8x7.

Excellent deal. You'll never beat that price. Well.........I did...I had a 25 and a 6 given to me on an old P-14 boat

Enjoy that little motor. It'll give you lots of good service if they're taken care of properly. Welcome to iBoats, BTW

 

[Kobie]

Re: 9.5 Johnson/Evinrude speeds

No weight, no slip, that's absolute theoretical maximum speed unless you are flying with a 30 mph tail wind.

Do the math. http://go-fast.com/Prop_Slip_Calculator.htm

Ok I'm not gonna argue over a prop calculator, I know what I saw on my gps, next time I will take a picture of the screen. As seen in my video, a 15 pushes that boat quite nicely, as will a 9.5 because that's what this thread is about.