Having real problems figuring out what to get

Raven Blayde

Cadet
Joined
May 28, 2008
Messages
9
My prop is shot on my Mercury 650hp outboard. So, I'm looking at these props and trying to decide what to get. Problem #1- I'm trying to run down the year of motor I have, but I'm finding lots of things that don't match up. The serial number on the motor is 2017585. I've been to 4 different websites where you can look up the serial numbers for Mecurys and according to what I've found, there are NO serial numbers like this on any 650hp mercurys!! ???? What the heck? I also found a sticker on the motor that says "Ohio 1979", but this must be a licensing number or something. The prop I took off has 15 teeth on the spline and "through prop exhaust". From what I've read, a 79' should be a 13 spline shaft, not 15. The prop I just took off has these numbers on it 698099-1
Anyway, the boat itself is a 16ft fiberglass thats going to be used for river fishing (not racing or going fast). Thinking of going with a Solas 21' pitch 3 blade prop (once I can verify what year this thing is) lol... Would a 21' pitch blade be good for what I have here, or should I go smaller? Thanks in advance. :D
 

steelespike

Supreme Mariner
Joined
Apr 26, 2002
Messages
19,069
Re: Having real problems figuring out what to get

You shouldn't make a change without your present prop size, max rpm and speed.Sticking a prop on without knowing specific info is a crapshoot both for performance and and motor health.My guess is the 21 is way too much prop.
A prop shop can size your prop, repair it and probably ID it. Then get your specs and you can figure if a prop change is in order.
 

Silvertip

Supreme Mariner
Joined
Sep 22, 2003
Messages
28,771
Re: Having real problems figuring out what to get

From what I can determine the part number you listed is a thrust washer for a 70 HP Force motor -- not a prop part number. I agree that 21P is way to much prop.
 

Raven Blayde

Cadet
Joined
May 28, 2008
Messages
9
Re: Having real problems figuring out what to get

Thanks very much for the replies! I'm betting this poor old motor has been peiced together in the past with who knows what. lol... I'll try doing more research (wish me luck).
 

Raven Blayde

Cadet
Joined
May 28, 2008
Messages
9
Re: Having real problems figuring out what to get

Okay, I think I've nailed it down to being a 66' 65hp motor. Has 15 spline shaft and "Through Prop" exhaust. Now I need to know what pitch I should go with. The boat is 15' fiberglass and will be used for fishing rivers and small lakes. I don't know what the rpm range is (boat doesn't have a tach), and I don't plan on running the daylights out of it. lol... Any pitch suggestions? Thanks in advance
 
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