87 y-150 plug fouling & breaking up

[John Koniewicz]

87 yamaha ,rebuilt carbs, yamahalube oil,good gas ... Constantly fouling plugs after 18 gal of gas ,plugs are all carboned up solid deposits. when first underway gets up to 5200 rpms 40 mph after 5min when gets at right temp breakes up bad, under load or above 3600 rpm ,whith new plugs same problem , it smokes like hell at idle could be a oil injector problem but I'm leaning toward an ign. module . Any thoughts appriciated

 

[Ray Neudecker]

Re: 87 y-150 plug fouling & breaking up

Much more likely to be a fuel problem. I would go back through the carbs again and retest the fuel pumps.

 

[John Koniewicz]

Re: 87 y-150 plug fouling & breaking up

fuel pumps checked out carbs fine.. dosent break up till warmed up

 

[jk1162]

Re: 87 y-150 plug fouling & breaking up

Is the electric choke staying open? Perhaps one of the heat sensors.

 

[jk1162]

Re: 87 y-150 plug fouling & breaking up

I ment electric choke staying closed.

 

[Ray Neudecker]

Re: 87 y-150 plug fouling & breaking up

Have you checked the link and sycn on the carbs or the adjustment for the choke? Be sure when you release the choke switch that the chokes all return to full open position.