Won't idel unless I keep throttled up. 1972 Johnson 50 hp

[RandyJ]

I've had this to happen on many old outboards. I've cleaned the carbs, put in new spark plugs and fiddled with all the linkage, idle screws, etc. And I've read everything Joe Reeves posted on adjusting carbs. Still, it runs pretty smooth, has equal tho I wouldn't say great spark. When I try to back down the warm up lever (neutral throttle) it dies unless I keep the carb throttles open with my hand. I can adjust the throttle cable and throttle on the engine pretty much all the way out and it will stay running long enough for me to slam down the warm up lever and throw it into gear. I'm not sure what to suspect since there's not all that much to these engines. The carb is clean, good compression and good spark.... of course, I'm trying to do this with as little work as possible and it will be a few days before I can get carb kits but after cleaning the carbs there was little noticible change in the way this motor runs. It had been sitting for 5 years with me occassionally turning it over. The inside of the carbs had a little "green" and some corrosion on the high speed jet but all is VERY clean now. I can squeeze the primer bulb really hard and tell the float is doing its job. When I check the plugs they appear to be wet and black.... but sometimes when it decides to be difficult to start I have to squirt gas/mix in the carbs then it starts right up. Tho' most of the time it starts right up. It will crank and run on either cylinder, one at a time. Since it has a power pack I assume there is little I can clean/adjust to improve spark...????

[brainkandy]

what ratio mix are you running? check manual or online for correct mix ratio, i believe most are 50/1, but dont quote me on that.
have you messed with the mix screw? check the manual for factory setting
what plugs are you running? possibly try running a set thats one step hotter than current

have you opend it up a bit to burn off some of the fuel? 2strokes are pron to loadup when at low rpm for a length of time, and there could be many reasons for the idle issues. but i would look into these simple fixes first.

[RandyJ]

I've got the correct spark plugs according to Champions site. Idle mixture screws have been set and adjusted to best performing settings and according to Joe Reeves recommendations. I'm a bit busy for the next few days but plan to FINALLY get around to building a good spark checker since I've got several old outboards I need to get running and find homes for. For some reason I feel this motor has weak spark tho' it does run and gets what appears to be good spark on both cylinders. I want a GOOD spark checker just to prove it to myself and to confirm one way or the other.... then I'll know which direction to go. I just don't feel this is a carbureator issue since carbs have been very well cleaned and adjusted.... I could still be wrong but the needle valve looks good and cleaning the carbs made no difference in performance.