Gear ratio

[johnmark]

I have a 1983 Johnson 50 hp (J50BELCT) what would the lower gear ratio be? and what should the RPMs be @ WOT? Thank You, John

 

[TN-25]

Re: Gear ratio

According to the 1983 brochure, the gear ratio is 12:29 (.414). It was rated at 50 h.p. @ 5000 rpm. Full throttle operating range is 4500 - 5500 rpm.

Curiously they also offered a 60 horse version of that very engine (44.99 c.i. or 737 cc; same as the 50) the same year (1983) that was apporoved for operating from 5000 - 6000 rpm at full throttle (it made 60 horses @ 5500 rpm.)

 

[Faztbullet]

Re: Gear ratio

12:29 or .414 comes out to 2.07 to 1 ratio

 

[ezeke]

Re: Gear ratio

12:29 or .414 comes out to 2.07 to 1 ratio

The factory service manuals and owners manuals express propeller gear ratios as TN-25 has shown.

It takes 29 engine revolutions to turn the propeller shaft 12 revolutions, I believe that would be a ratio of 2.416667 to 1.

 

[johnmark]

Re: Gear ratio

Thanks Guys I looking at getting a new prop. I'm going to fool with trying without the hydrofoil and diff. trim holes (Settings) to see if the rpms change any. maybe more weight to the bow.