Updated OEM carb jet specifications?

Theoutdoorsman

Senior Chief Petty Officer
Joined
Mar 6, 2003
Messages
669
I'm about to rebuild the carbs for my 1979 Evinrude 140 and was wondering if anyone has heard of any updated OEM carb jetting specifications. The reason I ask is because I inquired, before deciding to do this overhaul work myself, about a powerhead whereas the mechanic spoke of updated OEM carb jet specs. Just curious as to whether or not there have been any that I'm not aware of. New one on me. Thanks a bunch.............ALAN
 

Captain Jeff

Petty Officer 2nd Class
Joined
Jun 15, 2005
Messages
159
Re: Updated OEM carb jet specifications?

I'm not sure of the exact specs on your carbs but I have heard from several people who recommend re-jetting one to two sizes larger due to gasoline with 10% ethanol. I'm not sure what gas mix you have in your part of the country but this may be why you've heard about new jet specs. Good luck
 

Theoutdoorsman

Senior Chief Petty Officer
Joined
Mar 6, 2003
Messages
669
Re: Updated OEM carb jet specifications?

Where can I find this information on the percentage here in central Kentycky? Just curious if others would recommend this change in jetting. Thanks...........ALAN
 

ezeke

Supreme Mariner
Joined
Sep 19, 2003
Messages
12,532
Re: Updated OEM carb jet specifications?

Do you think the current jets leave the engine running lean?
 

Theoutdoorsman

Senior Chief Petty Officer
Joined
Mar 6, 2003
Messages
669
Re: Updated OEM carb jet specifications?

I'm not really sure. I am in the process of rebuilding this motor and am trying to take every precaution I can to ensure a nice long life out of her afterwards. In breaking it down, I did notice a LOT of build-up throughout the exhaust area of the motor. However, after talking to the folks at Mar-Fab, I have learned that this is common trait for this engine to begin with. Especially after the poor fuel issues hit the scene several years back. Coupled with this, the build up issue only got worse for these motors. But in my case here, I believe, build up this bad was likely the result of poor maintanace and some ignorance on my part as well. I'm only trying to prevent any problems in the future and trying to gain a little knowledge along the way. Steps I plan to take from here on out include: Decarbing with Sea Foam periodically to clean this build-up out BEFORE it has a chance to ruin another summer of mine, adding a fuel stabilizer with every tank of fuel, and basically keeping my engine well maintained. Overhauling this engine is NOT something I want to do every year or two.......LOL. I was leaning towards leaving everything in the carbs as is. As far as the jetting is concerned. I'm just curious as to what other opinions might be out there concerning this issue. Thanks............ALAN
 
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