Choke Problem-4.3LX/ Weber 4-bbl

[Woody-jh]

1995 Regal. 4.3LX Mercruiser, Weber WFB 4-bbl. Diaphragm activated, Non-electric Choke.
Problem just started last week. The engine will not start until you manually close the choke plate. Then it starts immediately...starting is not supposed to be a 2-person job!!
I'm novice, but have checked in both Seloc Manual, Mercruiser Page 5C18 schematics and wiring diagrams in both manuals and can offer the following:
1) Choke plate is always open unless manually closed.
2) Diaphragm/ Choke Pull-off is extended out until the engine starts. Then it is pulled in (the side that faces the choke linkage)
3) All link parts on both starboard (diaphragm) side and port side are moving freely.
4) I found one purple wire with a female end and insulating boot that I can't find a home for- it has 12V when the ignition is on- I just taped over the insulating boot.
5) Also found 2 black wires with ring connectors that don't have a home either- no voltage on them. Possibly for the "old style" outdrive bottle? I have the "newer" square bottle.
6) What does the "Choke Pull Off Linkage Rod" do? The top end is secured into a connecting plate. The bottom end just floats in a "chamber" that I can't even find on the schematics.
7) Why is the choke plate not closed until the engine starts from "cold start-" ambient temp is only 60 degF right now. Funny thing is that I had no problem starting the boat on muffs at home, then I move it to a marina (stacking service) and it now takes two to start...

Thanks...good advice always on this site...I need it, cause that is what will keep me in boating...shops have their place, but I can't run there every time.

 

[Don S]

Re: Choke Problem-4.3LX/ Weber 4-bbl

Got a picture? There isn't any such thing as a diaphram operated choke. There is a pull off that open the choke about 1/8" or so when the engine starts, but it doesn't close the choke.
Sounds to me like you have the electric choke coil missing, not hooked up, or something.

 

[Woody-jh]

Re: Choke Problem-4.3LX/ Weber 4-bbl

Here is the link to the Merc Manual that I am referencing. Both Seloc and Merc state that the 2-bbl has an electric choke, but I am drawing blanks on the 4-bbl. I don't understand just what closes the choke plate
http://www.boatfix.com/merc/Techbk/95/95hgcv.pdf
I can take a photo tomorrow if that helps.
Thanks

 

[Don S]

Re: Choke Problem-4.3LX/ Weber 4-bbl

I can take a photo tomorrow if that helps

.

Yes, take a picture. Your pictures from the tech manual does't even show the choke coil. But we need to see what YOU have, not what's in the manual.

 

[Woody-jh]

Re: Choke Problem-4.3LX/ Weber 4-bbl

Don, here are the photos. Hopefully I got what you need to see- if not, I'll get more. Of course, it started to rain just as I was getting the pics. PS, engine was stone cold and as you can see the choke plate is open. I had not operated the throttle for these pics, but the choke plate was still wide open yesterday when I had the ignition on and pumped the throttle.

Thanks,
Woody-jh

 

[Don S]

Re: Choke Problem-4.3LX/ Weber 4-bbl

You forgot the pictures?????

 

[Woody-jh]

Re: Choke Problem-4.3LX/ Weber 4-bbl

The site rejected them due to size-I'll try to resize them, else I will have to reshoot with less resolution.

 

[Woody-jh]

Re: Choke Problem-4.3LX/ Weber 4-bbl

2nd attempt after resizing...hope I didn't make them too small.
Woody-jh

 

[Woody-jh]

Re: Choke Problem-4.3LX/ Weber 4-bbl

Attached is the wiring diagram from the Seloc manual. It says electric choke for 2-bbl only. That's what is confusing me- just what operates the choke on the 4-bbl?
Woody-jh

 

[Don S]

Re: Choke Problem-4.3LX/ Weber 4-bbl

Your pictures are too small to see any detail, but in the one second from the left I see you don't have an electric choke. You probably have the choke coil mounted to the intake manifold with a piece of linkage to the choke.
Go to the Merc OEM manual and look at pages 5C-17

 

[Woody-jh]

Re: Choke Problem-4.3LX/ Weber 4-bbl

Don,
Check out Page 3A-20 in Manual 18 that talks about an "automatic choke" for V6-GM engines like mine. This section talks about the choke staying on too long, but not about what makes the choke "automatic" to begin with. I'm not sure what an automatic choke is as they describe it. If it requires a special gasket and I don't have it, there's not much that I can do without doing a partial teardown(ouch!)
http://www-alt.mercurymarine.com/mnetdata/SERVICE/CRUISER/Servmanl/18/18covr2.pdf

 

[Woody-jh]

Re: Choke Problem-4.3LX/ Weber 4-bbl

Last year when I had "poor cold-start" saga, it turned out to be a small piece of dirt in the anti-siphon valve on the tank. I have been focusing on the choke this year, because the boat starts well when you manually choke it- found that out by accident. If I have an automatic choke and don't want to do the teardown, then maybe I need to recheck the anti-siphon valve and perhaps change the fuel-water separator. Could my problem be that I am not getting enough fuel to the carb for a cold start? Am I "artificially" enriching the fuel that is there by manually applying the choke to make it richer?

 

[Don S]

Re: Choke Problem-4.3LX/ Weber 4-bbl

Your biggest problem now, is you won't listen.
You don't have to take the manifold off. You have to get the choke coil (mounts on the manifold) and linkage hooked up. Page 3A-20 has nothing to do with your problem,
Go to http://photobucket.com/ start an account and post a picture big enough to see. If you go to the page I told you about in the oem manual, it will show you where the linkage hooks up. And from what I see in your little pictures, there isn't an linkage there. ........... YOU have missing parts.

 

[Bondo]

Re: Choke Problem-4.3LX/ Weber 4-bbl

Your biggest problem now, is you won't listen.

Ayuh,.....

 

[Woody-jh]

Re: Choke Problem-4.3LX/ Weber 4-bbl

Lesson learned- my apologies.
Today I got my head back in there again, took more photos and added to the sketch that Don S sent from Merc Manual (Weber 5C16)
It looks like the starboard side choke linkage is detached from the choke coil located at the base of the carb. I can clearly see the choke coil and the linkage runs freely up and down on the outside of the coil. The bottom of the linkage has a nice 90 degree leg that looks like it should be attached to something to pull the choke closed. Photo and sketch attached. I tried to remove the choke coil housing- 1 screw that I could see, but couldn't get anything to even think of moving. Put the housing screw back in.
Can the choke coil housing be removed independent of the carb?
Can I re-attach the linkage to the coil, or does it leave the factory attached already to the coil, ready for attachment to the upper mounting plate?
A non-operative choke sure makes the engine a bear to start and keep running, unless you manually close it...

 

[Don S]

Re: Choke Problem-4.3LX/ Weber 4-bbl

You should be able to lift the cover off the choke coil enough to see the hole in the spring where the linkage fits (UNLESS it's broken) then. if you can't get the choke coil out of there, pull the carb. The fuel line, linkage and 4 nuts and it's off (get a new gasket to put it back on.

 

[Don S]

Re: Choke Problem-4.3LX/ Weber 4-bbl

One other note in case you have a broken choke coil and want to use the boat. WIRE THE CHOKE OPEN !!!
The boat will run fine, you may need to pump the throttle a couple of extra times to get it started, but it will start. Then keep the rpm up around 1200 rpm for a few minutes for the engine to warm up. After that you shouldn't need to pump the throttle more than once to start it within the same day of running. IF it doesn't start right off, give it a pump or 2.

 

[Woody-jh]

Re: Choke Problem-4.3LX/ Weber 4-bbl

What I am finding is that it will not start unless I manually close it. Once running...at 1200 RPM min as you note, it will run fine after warm-up. If it stalls, then I have to manually choke it again.
I will try to open the choke coil housing- I haven't seen them in the manuals, so I have been running a bit blind. Yes, it is Canada Day/ Independence Day time, but perhaps one of our dealers might have a new choke coil that I can use to figure out if I can repair the one I have.
Thanks for the advice...

 

[MikDee]

Re: Choke Problem-4.3LX/ Weber 4-bbl

Yes, the choke coil has a small loop in it on the outside end, the rod just slips into it, with the choke coil cover holding it in place.

 

[Maclin]

Re: Choke Problem-4.3LX/ Weber 4-bbl

I hope you can get the choke working, but it should start with just pumping the throttle a few times then leaving it open some for a fast idle to warm up.

It is called an automatic choke because it works with no intervention required from the operator. The choke plate is linked to the choke coil in the manifold, this coil winds up tight when cold and unwinds as it warms up. It is a bi-metal coil, one side heats faster than the other and this difference in reaction to heat is what makes the coil wind or unwind. The choke coil sits down in a well in the intake manifold, this well is also called the choke stove. The intake manifold has exhaust crossover passages that heat up from the exhaust, this heats up the stove and the choke coil reacts and pulls the choke plate open in a controlled manner.