1979 Johnson 115 Acceleration

[redraider08]

I have a 79 Johnson 115 on a 17' ranger boat. When pulling a skier out of the water i have to give it a little throttle before gunning it or the engine will dye. I think when i attemp to accelerate quickly the carburetor may be flooding. Is there any adjustment i need to make that could fix this problem? Thanks!

 

[ryguy1101]

Re: 1979 Johnson 115 Acceleration

If I understand carb mechanics accurately I'm pretty sure you can't flood the system that quickly. When you throw the throttle forward the engine at first is feeding off the fuel in the bowl of the carbs, and then the fuel pump catches up to the increased RPM and adds fuel to the carb as consumed by the engine. Have you checked your plugs yet to try and diagnose any air/fuel mixture or delivery problems?

 

[fireman57]

Re: 1979 Johnson 115 Acceleration

you might do a quick link n sync on your carbs. Sounds like your air/fuel mix is off.

 

[emdsapmgr]

Re: 1979 Johnson 115 Acceleration

Is your idle set too low? Possible the engine is running on the lean side at idle until you throttle slightly and it starts to suck from the main jets. Overhauled the carbs lately?

 

[redraider08]

Re: 1979 Johnson 115 Acceleration

I have not looked at anything to diagnose the problem yet. The carbs haven't been overhauled in a few years but i went ahead and got the overhaul kits for both of the carbs and the fuel pump. I will check the plugs and most likely replace the plugs as i have not replaced them this year then speed up the idle a little and see if that helps. Is there something on the carb to adjust the air/fuel mixture? Thanks!

 

[emoney]

Re: 1979 Johnson 115 Acceleration

I think you'll be happiest with that decision. These older outboards weren't built with ethanol in mind, so a bi-annual cleaning in fresh water is a great idea. There's definitely a mixture screw, but I'd have to be at home in front of my manual to tell you exactly where it is. I'm assuming it's similiar to my '79 140. If no one jumps in today, I'll look at it tonight and repost. I'd take a close look at the fuel line all the way from the carbs to the fuel tank while I was at it, just in case. Nothing more frustrating than to rebuild the carbs only to find a piece of delaminating fuel line clogging the jets up in a week or two.

By the way, here's a good video of a guy rebuilding 'Jonnyrude carbs;
http://www.youtube.com/watch?v=o5cxBMDezuU