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4.3LX & Weber Carb Service

Swedefj40

Swedefj40

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So I'm trying to dial in some issues on my 1996 Mercruiser 4.3LX 4bbl Weber carburetor. The motor has about 800hrs on it but not sure about the carb. I have a new Fuel/water filter, and recently a new fuel pump installed.

So what I'm experiencing is that it runs a little rough at 1st start up. Almost like it's missing a cylinder and I have to wait a good 5 minutes of about 2000 to 2500 rpm before I can punch the throttle to get up on plane. If it's a little cold it'll bog down slightly however, if I gradually push the throttle, she'll go. Not a big deal, just annoying. When it's warm, it's fine, no problems.
Now that I have the boat home, I made up a VIDEO of a cold start. If you have any expertise on a Weber/Edelbrock 4bbl Carb and 6 minutes to kill, let me know your opinions on how it looks/sounds etc. I'm curious to know about the choke position as it gets warm and what (or why) the little fuel squirting nozzle thing on top of the carb is doing?

I plan on adding a 1" phenolic spacer and I'll also do a carb rebuild at some point this winter.

Thanks in advance peeps.
 
The choke appears to be very sluggish....could be the coil is old and tired or it could be marginal (dirty) electrical connections to the choke...

I'd say doing the carb adjustments by the book would be a good thing...the various settings usually need to be done in the proper order to get things dialed in...I'd expect the choke adjustments to be significant contributors to your current conditions...

As far as the fuel squirting up - that is not normal...and I can't tell exactly when it is getting launched from (I'd guess one of the bowl vents). If you are going to overhaul the carb, I'd expect the new parts in the rebuild kit will mitigate this (assuming proper adjustments)...
 
My experience with Weber carbs used on Mercruisers is they get dirty on the insides and do seem to require a disaasembly and clean and rebuild with new parts. How long of time is dependent on how many hrs of use....

I think it would be best to plan on a complete rebuild and see what the results are after.
 
Yeah, a rebuild is in the works. I'm also tossing around the idea of switching to an electric choke instead of the divorced choke. Thoughts?
 
My thoughts/opinion would be to purchase a Marine Edlebrock carb and you will never look back.
The fuel line fits so no issues there.
May need a adaptor plate so a bit more research is needed.

I believe the intake manifold used was originally designed for Rochester Quadrajet spread bore where as the Edlebrock is a square bore. This is true for V8's not sure about the V6

I have done this change on V8' s only but the difference is day and night in the way it runs.
My opinion!
 
It is the Marine version of the Weber\Edelbrock carb. The manifold is a square bore designed for the carb. The reason for adding the spacer is to help prevent heat transfer to the carb which, theoretically, helps reduce the evaporation of fuel in the float bowls.
 
The Weber is different than the Edlebrock.

The Weber is a marginal carb. Works good but also has lots of issues over time from what I have seen.

Replacing it with a marine Holley or Edlebrock can be a game changer.....
 
Weber carbs are just plain different. They need lots of love and if they don't get it they go on strike. That said, most carb problems are in the distributor. Be sure that you have all good everything...cap rotor wires plugs timing...before throwing hate at the fueling.
 
The whole Ignition side of things were replaced 2 years ago (Cap, Rotor, Coil, Wires, Plugs Etc.)

The number on the side of the carb says it was manufactured in July 2005, would this still be made by Weber or now Edelbrock? I always thought they were identical anyway. They look identical. What are the differences?
 
Swedefj40 said:
So what are the differences between the Weber and Edelbrock? They look identical.
Click to expand...
Ayuh,.... That's what I want to know too,.....

I've been servicing Merc/ Weber carbs with edlebrock parts for well over 20 years, without any issues,....
My experience says they're exact carbon copies of each other,....
 
being as Weber made the casting for Edelbrock ages ago, I'd suspect the main pieces are identical...at least between the 1409/1410 and the WFBs.

Like Bondo, I don't know of any issues using the edelbrock service parts on the WFBs...
 
bondo said:
Ayuh,.... That's what I want to know too,.....

I've been servicing Merc/ Weber carbs with edlebrock parts for well over 20 years, without any issues,....
My experience says they're exact carbon copies of each other,....
Click to expand...
My eddy 1409 has Weber cast into the body. Pretty sure the 1409/1410 are the same as the weber 4 bbl merc used. Only parts exception are the units that use 2 stage step up rods. Also pretty sure the street 1406 I have on my Pontiac says weber in it as well. I have found that floats, needle and seat, jets and step up rods fit from my old Ferdeal Mogul era AFB "Strip Kit" Fit my modern edelbrock carbs.

The newer Edlebrock AVS and AVS 2 have some changes to adjust the secondary air door and on the AVS2 they use annular booster vs the down leg standard booster on the weber /1409/1410
 
Dieter said:
I have found that floats, needle and seat, jets and step up rods fit from my old Ferdeal Mogul era AFB "Strip Kit" Fit my modern edelbrock carbs.
Click to expand...
Ayuh,..... I've been using the same kit to tune webers for decades too,.....
'n when I have a question, I go to the edelbrock website, 'n look up the answer in their AFB Bible in the resources section,....
 
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