Re: QL 78YC or L78YC ?? {timing 140 rude 86)
About increasing your idle air jet size, it takes about 4 or 5 sizes just to notice a slight difference, because we are talking air here, not fuel. On some motors, going up 10 or more sizes is not unheard of.<br /><br />Years back there was a fix for certain early looper V4's that consisted of drilling a vent hole and installing a hose to eliminate fuel-oil buildup under the lower crank bearing. A problem engine would idle fine for a short time, them blubber and emit a puff of blue smoke, then idle fine again for a time. The fix was thru the factory where they sent the fitting and a template, but I doubt its available any more.<br /><br />Is your water line close to the exhaust ports meaning the engine is deep in the water with a lot of backpressure?