Johnson 140hp Gear Ratio?

Havis

Recruit
Joined
Sep 26, 2004
Messages
4
I have no idea what my gear ration is. I'd like to have it for prop selection. The engines are Johnson 140hp 1989 & 1990 loopersw/ 25" shafts. Also, while we're at it: weight? Max RPM?<br /><br />Thanks!<br />Scott
 

Dhadley

Supreme Mariner
Joined
Feb 4, 2001
Messages
16,978
Re: Johnson 140hp Gear Ratio?

If you have the V6 "style" gearcase the ratio is 12:27 or .44 or 2.25:1. Basically youll have 14 1/4" diameter props. <br /><br />If you have the V4 style cases it'll be 13:26 or .5 or 2:1. Youll have props in the 13 1/4" diameter range.<br /><br />The rev limiter is at either 6200 or 6700. Probably 6200 but it depends on which pack you have. Target 6000 rpm with an average load.<br /><br />The motors weigh about 380 lbs each.
 

Havis

Recruit
Joined
Sep 26, 2004
Messages
4
Re: Johnson 140hp Gear Ratio?

My current props say 14.5 x 19, but I've got the V-4 engine. Could the previous owner have done that? The props are a little beat up, but I get 5800-6000 rpm WOT, depending on load. So I guess the pitch is right. right?
 

Dhadley

Supreme Mariner
Joined
Feb 4, 2001
Messages
16,978
Re: Johnson 140hp Gear Ratio?

Youve got the V6 "style" gearcases. Same size but different ratios. Thats what 25" V4 loopers came with then. <br /><br />Sounds like youre right on as far as the set up goes. If youre so inclined, play with the set up and see if you gain rpm. Maybe you could go to 20 or 21's.
 
Top