OIl Mixture in 1987 OB Motor

Status
Not open for further replies.
Tsatzsue

Tsatzsue

.
May 16, 2011
556
Macgregor V-25 Charlton, MA- Trailer
I am mainly looking for advise. I have a Johnson Sea Horse 9.9 longshaft on my V25. The decal on the motor states to run a 100/1 oil to gas ratio. This seemed awfully lean to me so I ran it at 50/1 like every other motor that I have had mainly because I didn't want to blow up the motor. I seem to get a brown milky ooze out of the exhaust ports on the lower unit. Unburned oil sludge. I have read Leroy's Ramblings, a very informative link on these motors and am still not sure what the right mix is. I do know that at 50/1 I have had a couple hairy "no start" experiences. I sail in the ocean and it has happened too far from shore for comfort. Plug fouling is not acceptable. Last year I ran 75/1. Does any one have any good first hand knowledge on what is right? Any info is appreciated.
 
J

jimg

.
Jun 5, 2004
175
catalina 27 dana point
Use 50:1. They put 100:1 decals on those for a few years and went back to 50:1. The leaner mixture will work for commercial use, where motors are run for long continuous periods, but for the stop and start infrequent use that a sailboat would have, definitely 50:1. It won't blow up on the leaner mixture, but it will wear out faster. If you are having starting issues it is unrelated to the gas oil mixture.
 
T

tommays

.
Oct 2, 2006
1,517
Jboat J24 commack
jimg said:
Use 50:1. They put 100:1 decals on those for a few years and went back to 50:1. The leaner mixture will work for commercial use, where motors are run for long continuous periods, but for the stop and start infrequent use that a sailboat would have, definitely 50:1. It won't blow up on the leaner mixture, but it will wear out faster. If you are having starting issues it is unrelated to the gas oil mixture.
Click to expand

Yes the 100:1 was a short BAD experiment with the biggest issues during off season corrosion
 
THECUSCUS

THECUSCUS

.
Sep 25, 2008
961
Macgregor & Island Packet VENTURE 25 & IP-38 NORTH EAST, MD
I have the exact same motor. I ran it at 100:1 for afew years until I read a lot of others were running 50:1. Now I use a mix in between. I look at the mixing ratio chart on the oil container and round up to the nearest whole number or so, and go alittle over that line on the measuring cup. It's kinda like mom's cooking, a splash of this and a pinch of that. BTW, I too have that brown milky crap coming out the lower exhaust, an it's there regardless of the mix. I just wipe it off when I can. I also keep the motor mount all the "up" and the motor tilted when ever it's not running. I found with mine that it won't start if the choke is even a hair open. Make sure your choke lever isn't put on 180 degrees off ( it will go on and work and look right, but the choke plate will not close 100%). Check on Leroy's site about the choke. I had to use ether to get mine started until I figured it out. Now she fires up on the first or second pull.
 
W

Winkfish

.
Jul 28, 2010
914
Boston Whaler Montauk New Orleans
Just wondering, cuz I have a large outboard for my fishing boat. If there was brown milky ooze coming out, that would tell me I have water in the lower unit gear oil. Would it not be the same for smaller outboards?
 
caguy

caguy

.
Sep 22, 2006
4,004
Catalina, Luger C-27, Adventure 30 Marina del Rey
Winkfish said:
Just wondering, cuz I have a large outboard for my fishing boat. If there was brown milky ooze coming out, that would tell me I have water in the lower unit gear oil. Would it not be the same for smaller outboards?
Click to expand
Yeppers. I have the same motor in a 15hp long shaft and had the same question. The guy I bought it from, a ob mechanic, suggested 50:1. Adjusting the air/gas mixture is a real pita on this motor. I was constanly concerned about running it too lean and burning the motor up that way. I switched to a 18 hp 2 cycle Tohatsu and love it.
 
Status
Not open for further replies.

Top Bottom