shaft extension 20hp johnson

[rbyrum]

i have a johnson 20 hp (R8545205)short shaft and want to change tolong shaft.any help would be appreciated.<br /> steve

 

[Joe Reeves]

Re: shaft extension 20hp johnson

The model number, not the serial number, will be needed so that we can determine the exact year.

 

[rbyrum]

Re: shaft extension 20hp johnson

the only other numbers i can find are on the transom mount,they are 188054and 01101

 

[Joe Reeves]

Re: shaft extension 20hp johnson

The plate on the transom bracket is the correct area. However, take a closer look at the number you list as 188054 which would be the model number.<br /><br />There is no such number in the book I have. Is it possible that the number is actually 18305 or 18503 ?

 

[rbyrum]

Re: shaft extension 20hp johnson

joe those numbers are stamped into the top of the transom mount.I see a place on the side where a plate could have been but its gone.

 

[rodbolt]

Re: shaft extension 20hp johnson

is it through hub exhaust with a splined prop shaft or a pin drive prop with an above the prop exhaust snout ?

 

[rbyrum]

Re: shaft extension 20hp johnson

it is through hub exhaust with a splined prop shaft

 

[Joe Reeves]

Re: shaft extension 20hp johnson

I understand the number problem. If that initial number you listed isn't from a core plug (looks like a small quarter size freeze out plug) on the powerhead, look for that core plug.<br /><br />If the number(s) on the core plug are different from what you stated initially, what are they?

 

[rbyrum]

Re: shaft extension 20hp johnson

the number on the core is R8545205

 

[Chinewalker]

Re: shaft extension 20hp johnson

If I'm not mistaken, the "R" prefix usually means that it's a rebuilt or remanufactured powerhead. The model number may be lost to the sands of time on this one. The thru-hub exhaust narrows it down a little bit. Possibly late 1980s? If that's the case, pretty much all of the kits for the 20-35hp 2-cylinder thru hub exhaust motors from about 1985 upwards should work...<br /><br />- Scott

 

[rbyrum]

Re: shaft extension 20hp johnson

thanks for all the info guys.I guess ill call around and see if i can locate one.anyone have a part number?<br /><br /><br /> thanks again,<br /> steve

 

[MarkCz]

Re: shaft extension 20hp johnson

I bought a long shaft conversion kit for a 1985 20 hp outboard from this guy on ebay. email ariotti@tampabay.rr.com or call 727-442-4479 I understand that he had a few of these and a friend of mine purchases one from him a month ago.

 

[rbyrum]

Re: shaft extension 20hp johnson

thanks MarkCz,I'll give him a try

 

[rodbolt]

Re: shaft extension 20hp johnson

the 99 accesories manual lists part 396707 for 20 to 35 from 85 thru 99.list in 99 was 232.74 dollars comes with everything you need except oxy/acetylyne to get the old stuff apart. try Ron's marine in portsmouth VA and tell him a guy in kitty hawk refered ya.

 

[rbyrum]

Re: shaft extension 20hp johnson

thanks rodbolt,i've already got it apart.i'll give him a call

 

[rodbolt]

Re: shaft extension 20hp johnson

the kit comes with new upper and lower mounts. the long shaft needs stiffer mounts than the factory short shaft. the mounts are sometimes difficult to remove.