Quadrajet Rebuild
05-07-2003, 12:08 PM
#1
Guest
Posts: n/a
Quadrajet Rebuild
Help!
1983 Crusader 350/270 hp Chevys. Split-Fire Plugs in port engine, look great.
Ran Split-Fire plugs in Starboard engine, and fouled them out in 30 hours, and replaced them with Champions, shown.
It would appear the starboard engine is running way too rich.
I have taken apart the starboard carb, see following pictures for clarification.
1983 Crusader 350/270 hp Chevys. Split-Fire Plugs in port engine, look great.
Ran Split-Fire plugs in Starboard engine, and fouled them out in 30 hours, and replaced them with Champions, shown.
It would appear the starboard engine is running way too rich.
I have taken apart the starboard carb, see following pictures for clarification.
05-07-2003, 02:27 PM
#9
Gold Member
Gold Member
The rods maked "AV" are the secondary metering rods which are controlled by the large rear air doors.
The others are the primary metering rods. Controlled by vacum.
The jets only control WOT fuel flow, metering rods take care of all part throttle fuel flow. Secondary jets are not removeable.
The parts shown look real dirty. Could use a good cleaning.
As for the over rich condition, the float could be saturated with fuel, debris could stop the inlet needle valve from closing. Either one could cause excess fuel to dump into the mainfold. Maybe a clogged air bleed could do it too.
I'd be looking into a rebuild kit, Merc part number 823436A 1.
I have the same engine (only a 1988 version) and that's the number for the kit to rebuild mine. Check with Mercury to be sure.
If you have Dennis Moore's book "SMALL-BLOCK CHEVY Marine Performance" good, if not, get it. Also pick up HP Book's "ROCHESTER CARBURETORS". Both are "must haves" if you need information.
The others are the primary metering rods. Controlled by vacum.
The jets only control WOT fuel flow, metering rods take care of all part throttle fuel flow. Secondary jets are not removeable.
The parts shown look real dirty. Could use a good cleaning.
As for the over rich condition, the float could be saturated with fuel, debris could stop the inlet needle valve from closing. Either one could cause excess fuel to dump into the mainfold. Maybe a clogged air bleed could do it too.
I'd be looking into a rebuild kit, Merc part number 823436A 1.
I have the same engine (only a 1988 version) and that's the number for the kit to rebuild mine. Check with Mercury to be sure.
If you have Dennis Moore's book "SMALL-BLOCK CHEVY Marine Performance" good, if not, get it. Also pick up HP Book's "ROCHESTER CARBURETORS". Both are "must haves" if you need information.
Last edited by Iggy; 05-07-2003 at 02:32 PM.
05-07-2003, 02:41 PM
#10
Gold Member
Gold Member
If you do decide to rebuild it yourself pickup the carburetor soaking chemical and two or three cans of spray carb cleaner. Make sure the cans come with the little tube (like WD40 has) so it'll spray in small places.
Spray the cleaner through all passages before soaking and do it again after soaking to be sure they're all clear. Squirt it through every hole you can find. If you have compressed air, use that too. It can't be too clean.
I've always done it that way and never had trouble afterward.
Spray the cleaner through all passages before soaking and do it again after soaking to be sure they're all clear. Squirt it through every hole you can find. If you have compressed air, use that too. It can't be too clean.
I've always done it that way and never had trouble afterward.
