Rebuilding a spare carb to replace the one that's there

[JoLin]

I'll try to keep this short. Replaced one vortec engine in 2014 with a complete Merc Gen + 4.3 reman. The 4V Carter/Weber carb supplied with the engine was faulty, so I put on the old one until Merc replaced it, then I swapped them out and boxed up the old one.

Recently having flooding issues with the newer carb, so want to rebuild the old one and swap it on. The carb I have on hand is a Merc # 3361 9600s. That carb has a manifold choke rather than the electric choke on the newer carb.

1. Can I swap the electric choke onto the old carb? Is it just a matter of unbolting the old and bolting on the new, or is it more complicated than that?

2. I plan to rebuild the carb with an Edelbrock (1409) rebuild kit, and change jets and metering rods as follows:

.095 (part#1426) primary jets
.092 (part#1425) secondary jets
.065" x .057" (part number 1461) meter rods
7" pink step up springs

The above list is from the forum here, based on input from a few people who've tuned these things for a 4.3 vortec.

Am I approaching this right? I'm trying for minimal downtime on the boat. I want to be able to bolt on the rebuilt carb and go. I'm obsessing only because I haven't rebuilt a carb in 40 years.

My .02

 

[harringtondav]

My question is why the newer carb is flooding? Forum wisdom tends to point to float needle seating and/or float height. You can check these w/o sacrificing the newer air horn gasket.

 

[JoLin]

I'd rather disassemble that carb later, do a rebuild and change the jets and metering rods on that one, too. Since it'll be "optimized" (I think) for my 4.3, I can swap that one to the other motor.

My .02

 

[Bondo]

1. Can I swap the electric choke onto the old carb? Is it just a matter of unbolting the old and bolting on the new, or is it more complicated than that?

2. I plan to rebuild the carb with an Edelbrock (1409) rebuild kit, and change jets and metering rods as follows:

.095 (part#1426) primary jets
.092 (part#1425) secondary jets
.065" x .057" (part number 1461) meter rods
7" pink step up springs

Ayuh,...... I'd just buy the electric choke conversion for yer ole carb, 'n be done with it,......

Ya, the Edlebrock is Exactly the same carb,.....
At their website in the resources link is the Bible for those carbs,....
Everything you could ever wanta know 'bout 'em,....

They also sell a Street/ Strip tunin' kit that has a full assortment of needles, springs, 'n jets,....

I did mine the old fashion way,.... Change something, try it, 'n read the spark plugs,......
Ended up with the stock jets, with different needles, 'n springs,.....

 

[JoLin]

Ayuh,...... I'd just buy the electric choke conversion for yer ole carb, 'n be done with it,.....

I did mine the old fashion way,.... Change something, try it, 'n read the spark plugs,......
Ended up with the stock jets, with different needles, 'n springs,.....

I would if I could, but removing and reinstalling the plugs multiple times is physically more than I can manage. I copied the jet/metering rod specs from posts by 2 of the experts here who posted the same conclusions from their tests with 4.3 vortecs. Unfortuantely, I didn't note which members they are. I figured I'd follow their lead. If I nobody confirms, I can just buy the standard rebuild kit and go with that. The engine did/does run well with the stock setup.

My .02

 

[achris]

My question is why the newer carb is flooding? Forum wisdom tends to point to float needle seating and/or float height. You can check these w/o sacrificing the newer air horn gasket.

Weber 9600 and 9666S carbs are well known to flood on shutdown. The internal passages as small enough to allow for a 'capillary action' for the fuel to continue flowing and then drip down into the intake.

It was one of the reasons I sold my old 4.3LX and put the MPI in... Couldn't stop it doing it. I once pulled the top off a spare Weber I had and filled the float chambers. I then blow some air down one venturi until I had fuel flow, refilled the float chamber and watch as it drained without any air flow... The other stayed full. I talked to carb 'experts' about it, and all they could say was that what I was seeing can't happen.... So obviously my eyes were playing tricks on me, or I was asleep and dreaming... But that didn't stop the boat engine from being a nuisance to start after shutdown... Merc sort of acknowledged the problem by sending me a new carb. That one did the same.... And if you search here, you'll find a LOT of threads with the same thing....

And on merc's advice, I set the float level a couple of millimetres low, still did it...

Chris...........