Re: Mercruiser Quadrajet epoxy??
to seal the machining holes on the Q-jet, and most other crbs, they used a steel plug with an oring set in lead. over time they leaked.
most times it was simply annoying as the secondary jet plugs would drain the fuel bowl causing very hard starting due to no fuel in the bowl.
the foam gasket thing is worthless at best.
I use JB weld and epoxy ALL plugs at rebuild as some carb cleaners will cause a leak.
did my first Rochester carb school about 1978 in hayward CA, been doing Q-jets since I was about 16 and I am 47 now. in fact I did another yesterday.
the Q-jet was and is a dead reliable design that was first introduced about 1966.
however it can be rather touchy especially if there is any other issues than a dirty carb.
for automotive use the leaking main wells usually were not an issue as most cars did not sit for weeks between starts, boats dop and thats when you will find a dry fuel bowl. engine then must crank until the bowl is refilled and after that they will run flawless until they sit again.
if the primary passage plugs leak it can do all kinds of crazy low speed things, thats why I simply epoxy them all at rebuild.
but the triple venturi primary bores and the design of the secondary airvalve made it a very efficient carb for a 4bbl.
