Trying to fix neighbor's 351 in a well- maintained 1979 Nautique. Holly 4600 series carb professionally rebuilt for this problem a year ago - only about 10 hours on the rebuild and problem is back. It looks like too much gas dripping out the primary venturis at idle, but idles pretty good, but when shut off, gas pours out the primary venturis for 10 to 15 seconds flooding the engine. It will not start until it cools off unless you open the throttle all the way and crank for 10 seconds to deflood. Some gas even came out bowl vent. I've rebuilt over 100 carbs over the years, so I took a look. Everything looked fine but I replaced float and float valve needle and seat anyway with genuine Holly parts - problem seems slightly better (no gas out bowl vent) but still definitely there. Economizer valve appears to be OK. The secondaries are behaving OK. Float assist spring appears OK. Float level OK. Float not binding - that formed brass metal part that partially shields the bowl's vent outlet passage is mounted properly - not hanging down to hit the float. When carb is apart, I can turn the float chamber/float valve assembly upside down so the float closes the valve by gravity and I can't blow into the gas line, so valve is working. I'm thinking the float is somehow not cutting off gas and bowl is overfilling but don't know that for sure. Choke wide open.
Has anyone else had this problem? and how was it fixed?
Thx,
Dave
Has anyone else had this problem? and how was it fixed?
Thx,
Dave