Merc 4.3LX Weber carb choke questions

Hi guys, this is my first post although I've already learned quite a bit just searching the posts, so thanks for being so smart about boats and passing the knowledge on.

I've been out of boating for 20 years and just recently bought a 93 Regal with the 4.3LX/Alpha1/TBolt IV setup. It had been neglected but I've got it running really well by just doing the basic tune up stuff (dist, rotor, coil, wires, plugs, timing, fuel filter/separator, oil & filter, etc.) and running some Seafoam through to clean out the carbon.

Really the only other tuning issue I have is that it's hard to start when cold. The problem is that the choke won't close. If I manually close it, it starts right up. It's got what I guess is called the "Automatic Choke" with a rod running from the choke butterfly shaft down into a little box on the intake manifold that houses a metal coil. It doesn't seem to be electric so I guess it's activated by engine heat? Is that right?

I bought both the Seloc and Mercruiser factory manuals and amazingly, neither one has anything on this choke. They have info on the electric choke that is used on other carbs, with the black plastic housing on the side, but not on this Weber setup.

So here are my questions:

Is there a common problem with these chokes that I need to check?

The choke rod is hooked up on the butterfly rod, but I can't see down into the coil housing to see if it's come off there. Do I have to remove the carb to get it off? There's a screw holding it to the manifold but removing it does not allow the housing to come off easily. It might just be the seal to the manifold is stuck, but I didn't really want to start cranking on it until I knew the proper procedure.

I looked at a lot of Merc parts places (including iBoats), and either these choke parts are not listed, or they're shown as discontinued. Anyone know of a source if I need new parts?

Has anyone converted one of these to a manual choke? If so, where did you get your parts and what parts did you use?

Thanks for the help.

Re: Merc 4.3LX Weber carb choke questions

if the manuals you have don't mention the type of choke you have, then you have the wrong manuals - and get rid of the seloc, its garbage

the choke coil you have is operated by engine heat, its called a stove - it contains a coiled bimetal strip that will "unravel" when heated thus pushing on the rod to open the choke plate

chances are the metal strip has broken or come unattached at either end, remove the metal cover and inspect it for damage or otherwise

usually the screw holding it down is quite rusted so some penetrating oil will help dislodge it

Re: Merc 4.3LX Weber carb choke questions

Thanks dubs. It does seem weird that the choke isn't covered. I work on all my cars and have gotten factory manuals for every car I've bought, and have never had a factory manual that missed much. The Merc manual is the right one for my serial number and it has an entire section covering the Weber. But the only mention of choke is of the choke pull off and disconnecting the choke rod when removing the carb. Strange.

I didn't have a problem getting the screw out. The problem was dislodging the choke housing (or whatever the thing is called that the coil is in) from the manifold. It sits sort of under and against part of the carb body and on top of the manifold with little room to spare on any side, if any. I can't tell if the housing is attached to the carb or just the manifold. I was trying to get it out without having to remove the carb if possible. Does anyone know if the carb has to be removed to get it out?

Re: Merc 4.3LX Weber carb choke questions

The fact is all the 4bbl webers are harder to start than other setups. The thing is once they do get going they are much better performers and last alot longer than Quadrajunks. I have on in my 1993 4.3 lx and have been running it for 15 years and over 300 hours and haven't even touched it other than winterization and occasional cleaning.

Re: Merc 4.3LX Weber carb choke questions

I have a 4.3L that I converted to a 4 barrel Weber, so I'm familiar with the 'divorced choke' setup you have. The good news is the components are relatively cheap to replace. You really should only need a new choke coil and possibly rod to get it to adjust correctly. The coil should be tight when cold and uncoil as it heats up, so when the block is cold the coil and rod should be holding the choke plate completely closed. There's a slight amount of adjusting you can do by bending the rod, but not much. The rod linkage that the coil rod attaches to should also have another rod linked to the diaphragm that should pull the plate open 1/8 inch at idle via manifold vacuum if I remember correctly. I wasn't able to remove the choke coil housing without taking off the carb, but it's not that big a deal to do that (4 bolts plus the throttle linkage and fuel line). My guess is your coil is either broken or too weak to hold the plate closed.

Just as an aside I still prefer the divorced choke to the electric choke because the divorced choke will always reference the actual engine temperature whereas electric chokes are basically just heaters on a preset timer. Many an electric choke owner has complained that the chokes close off too quickly because they cool off too quickly after shutdown in a way that doesn't match engine temperature.

Re: Merc 4.3LX Weber carb choke questions

Kaplooi... if you happen to read this, nearly a year later, what's you're source for the choke coil? All last year I had a hard starting condition and I thought it was tied to my low WOT, but upon commissioning this year I found the choke not closing.

THanks,
Don