Plug colour

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dwarfy

dwarfy

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How many people check plug colour to get an idea of your tuning? Its not something I have really done Ive just tuned it by ear and by how well it runs and at the minute its absolutely flying :D

Out of curiosity I just looked at the plug in the bug as the primer bulb is constantly full and, remembering what was said on here somewhere about it should be half full as a guide for optimum running, thought it would be running very rich but its a nice dark brown so very slightly on the rich (safe!) side but not excessively.

Soooooo, regardless of the bulb being full and the plug being slightly darker than is regarded optimum Im leaving well alone!!

Just wondering how many take the plug colour and primer bulb status into consideration when tuning and how many do it by ear and performance alone??
 
i tune by plug colour and carb bubble and also by ear im happy doing it this way and haven't had any issues i look for a tan to choc brown colour and half bubble to 3/4 full bubble plus you can tell by performance,,a lot of people don't get the full from there engines thinking there going to blow them up by going to lean but if you go by plug colour and carb bubble you should be ok its more the petrol mix and running not enough oil that will do the damage
 
dwarfy said:
How many people check plug colour to get an idea of your tuning? Its not something I have really done Ive just tuned it by ear and by how well it runs and at the minute its absolutely flying :D

Out of curiosity I just looked at the plug in the bug as the primer bulb is constantly full and, remembering what was said on here somewhere about it should be half full as a guide for optimum running, thought it would be running very rich but its a nice dark brown so very slightly on the rich (safe!) side but not excessively.

Soooooo, regardless of the bulb being full and the plug being slightly darker than is regarded optimum Im leaving well alone!!

Just wondering how many take the plug colour and primer bulb status into consideration when tuning and how many do it by ear and performance alone??
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You want the fuel bulb to be full, half full is a lean mixture and will run hot
 
i don't think bubble means anything as far as tuning goes. it may be an indicator as to the popoff pressure in the carb but the needles still turn in and out and will adjust mixture accordingly no matter if bulb is full or half full. no fuel in bulb is bad, but only then. that usually is an indicator of vapor lock occuring.
 
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