Johnson/Evinrude carbs-What is the difference?

[sktr180]

I have a 1984 Johnson 140hp outboard. The numbers on the carbs are "393771 & 393772". From looking at a parts list I found out these are carbs for a 1984 115hp and have a 1 3/16" throat. What is the difference between the 115 carbs and the 140 carbs, and how will/could this effect performance?

 

[mnw001]

Re: Johnson/Evinrude carbs-What is the difference?

I have a 1973 ev 135 its carbs are 1 5/16<br />I also have a 1979 jo 140 its carbs are 1 3/8<br />I'm not sure but it sounds like it could affect your motor

 

[jimmbo]

Re: Johnson/Evinrude carbs-What is the difference?

Bigger venturies mean greater air flow, great air flow means more power.<br /><br />1 3/16 used on 85hp, 88hp, 90hp, and early(pre 1973) 115hp.<br /><br />1 5/16 used on 1973 - thru 115hp, 1973 -76 135hp, 1977 140hp. also on 1980 - 84 140hp, and 1985 - thru 110hp <br /><br />1 3/8 used on 1978 - 79 140hp

 

[sktr180]

Re: Johnson/Evinrude carbs-What is the difference?

Fishslayer and jimmbo, thanks. Sounds like I have the wrong carbs and could gain better performance form my motor. Do either of you have any part numbers for the carbs for a 1980-1984 Johnson 140 hp carbs? My motor is set up for electric primer choke.

 

[mnw001]

Re: Johnson/Evinrude carbs-What is the difference?

do you have performance problems with the present carbs<br />I'm not sure that you want to change them if not.

 

[jimmbo]

Re: Johnson/Evinrude carbs-What is the difference?

get a partsman to look up what the part #s for an 84 140hp. Next ?, if these are not the stock carbs, any idea when and why they were changed?

 

[sktr180]

Re: Johnson/Evinrude carbs-What is the difference?

The motor seems to run fine under normal conditions, but receintly had developed a rough idle and a slight drop in RPM. I had a mechanic check it over. Everything checked out, including compression. I purchased the motor used (did not think about its history) mounted on an older boat. Later upgraded boats and put this motor on the newer boat. (The motor on the newer boat---blown). After changing it to the newer boat seemed to be running fine. Not knowing if the carbs had been rebuilt, I got the kits to do just that, thinking that would solve the problem. While waiting on the kits to arrive (ordered), the mechanic fired it up and in checking noticed the throttle shaft was loose on both carbs. He said that it seemed to smooth out when he covered the holes. While taking the carbs off, I noticed the tags on each carb with the numbers I gave before, along with the numbers 115. Thats where I am today.

 

[G DANE]

Re: Johnson/Evinrude carbs-What is the difference?

The effect of worn throttle shafts can often be cured by jumping to next lower # iddle jets WHEN AIRJETS - if FUEL JETS of coarse next higher #. You will only nitice the bigger carbs if your motor/prop/boat combo is set up so that motor reach its maximum RPM with an average load. The holeshot is better with the smaller carbs, they have better flow at low rpm.