1964 Mercury 650 propeller and tachometer.

Fregata

Fregata

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Got a vintage Mercury 650 motor 2 weeks ago and "forgot" to check if the propeller was tighten right, so I had an accident and lost my propeller yesterday!
It was the org. propeller...anyone knows what diam. and pich I should be looking for (15 splines)?

Anyone knows what kind of tahcometer i need?

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chrome dome

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Re: 1964 Mercury 650 propeller.

Re: 1964 Mercury 650 propeller.

the only number l can see on my son's '64 650 is 17"
that is one good looking donk... the boats not bad either lol

we were hoping to get his looking that good...but..alas..it has a rather ghastly crack in the block now..
such is life,
 
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steelespike

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Re: 1964 Mercury 650 propeller.

Re: 1964 Mercury 650 propeller.

The guys at Johns Old Mercury Site.com may be able to help.
I'm sure they will need details on the size and weight of the boat
I assume it is a soft chined boat.
 
Fregata

Fregata

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Re: 1964 Mercury 650 propeller.

Re: 1964 Mercury 650 propeller.

Thanks, guys!

My little rare norwegian mahogny boat is a 15 footer with a weight of 250 kilos. I have no idea what diam. and pitch my former propeller was, but I was quite happy with it`s performance. Since my boat ain`t got a tach I don`t know what my WOT rpm was, but my top speed was aprox. 40 miles.
 
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steelespike

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Re: 1964 Mercury 650 propeller.

Re: 1964 Mercury 650 propeller.

Is the speed by gps? seems a little optimistic.
Assuming 40 is right gear ratio is 2.00 guessing slip at 7% and assuming motor at 5300 rated rpm the prop size would be 17".Thats a lot of guessing but a 17 is right in the middle of the chart.9" being smallest and 26 the largest. Consider that a starting point not a final selection.
 
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chrome dome

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Re: 1964 Mercury 650 propeller.

Re: 1964 Mercury 650 propeller.

Fregata said:
Got a vintage Mercury 650 motor 2 weeks ago and "forgot" to check if the propeller was tighten right, so I had an accident and lost my propeller yesterday!
It was the org. propeller...anyone knows what diam. and pich I should be looking for (15 splines)?

[]
Click to expand...

just went outside...beaut day btw.. and measured it..a tad over 13" so 13 x 17"
didn't take it off to check splines but it DOES look old lol
 
Fregata

Fregata

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Messages
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Re: 1964 Mercury 650 propeller.

Re: 1964 Mercury 650 propeller.

Thanks again, guys!

I got an offer from Sweden for a 2 blade 13 x 15"...maybe I`ll try it just for fun while I`m looking for a 3 blade 13 x 17"!
 
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steelespike

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Re: 1964 Mercury 650 propeller.

Re: 1964 Mercury 650 propeller.

Thanks for the help; but
no need to worry about diameter. If the prop is intended for the motor the diameter will be correct.If you check the chart you will see that to a degree generally as pitch goes up diameter goes down and manufacturers diameters may vary slightly brand to brand.
A 10" pitch has a 14" diameter and the 17 about 13.
 
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steelespike

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Re: 1964 Mercury 650 propeller.

Re: 1964 Mercury 650 propeller.

Fregata said:
Thanks again, guys!

I got an offer from Sweden for a 2 blade 13 x 15"...maybe I`ll try it just for fun while I`m looking for a 3 blade 13 x 17"!
Click to expand...
The 15" should get up quicker than the 17" and the pitch and 2 blade style will probably increase rpm.Usually a 3 blade will have better overall performance. Could be a fun trial.
But be aware it could over rev.You should add a tach For best performance and the health of your motor a tach is important. An induction tach like the Tinytach is reasonable and will
work on almost any motor.Also some use an optical tach for testing.
 
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chrome dome

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Re: 1964 Mercury 650 propeller.

Re: 1964 Mercury 650 propeller.

attachment's not working here
 
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steelespike

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Re: 1964 Mercury 650 propeller.

Re: 1964 Mercury 650 propeller.

Again the guys at Johns Old Mercury Site.com may be able to help.
Tachs can become inaccurate with age and I don't know if its from outside influence or age.
I believe the tinytach can be used like a hand held and can be set to work on a vast number of different motors.
 
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