2bbl carb problems

[fishingman220]

I have a 1996 5.7 2bbl, with the thunderbolt 4 ignition, well it has a electric choke, and it is not working, it never closes. what do i need to test to see if it getting power, and if it is, what do i need to replace?????

 

[Polar_Bus]

Re: 2bbl carb problems

I have a 1996 5.7 2bbl, with the thunderbolt 4 ignition, well it has a electric choke, and it is not working, it never closes. what do i need to test to see if it getting power, and if it is, what do i need to replace?????

1st simple check is open the throttle to 1/2, and move the choke butterfly. Does it move nice and free? If yes, move to next step.

The choke might just be out of adjustmernt. Loosen the 3 screws that hold the plastic housing and slightly rotate the plastic housing ( with the throttle open to 1/2 ). I can't remember exactly which way you rotate to get the choke plate to close (I believe its clockwise). If nothing is happening, completely remove the plastic housing and verify that the choke linkage is fitting into the metal coil hole eye. Try adjusting the close again. Might just be a corroded siezed choke coil.

 

[Maclin]

Re: 2bbl carb problems

It may help to keep in mind that the choke plate closes when cold via the mecahnical linkage from the choke's bimetal coil. The "electric" part is a heater that heats the choke coil causing it to open at a controlled rate once the ignition is on.

 

[Bondo]

Re: 2bbl carb problems

Ayuh,...

When doing a Cold Start,...
The Choke should set when the throttle is moved to WOT,+ returned to maybe 1/2, 1/4 travel....
The wire at the Choke should be Hot, whenever the key is "On"... It helps to pull the Choke, Off,...

The Manual, found Here, explains it all...

 

[fishingman220]

Re: 2bbl carb problems

so if it was working correctly, then when the motor is cold, it should close when you turn the key on, right???

 

[Bondo]

Re: 2bbl carb problems

so if it was working correctly, then when the motor is cold, it should close when you turn the key on, right???

Noooo,.... The Electrical Power is used to Pull the Choke OFF.....

When doing a Cold Start,...
The Choke should set when the throttle is moved to WOT,+ returned to maybe 1/2, 1/4 travel....

 

[fishingman220]

Re: 2bbl carb problems

so if i turn the key to on and pump the gas to wot, then back it to 1/2, the choke should be on??? right??

 

[Maclin]

Re: 2bbl carb problems

"so if i turn the key to on and pump the gas to wot, then back it to 1/2, the choke should be on"


Leave out the "turn the key to on".

When engine is cold push the throttle past half way then return to zero. Choke plate should be closed then. Key on or off makes no difference if the engine is cold. Well, it can make a difference if you leave the key on too long because the choke can heat up and open.

Some marine carbs do no even need you to move the throttle, the choke plate linkage can allow it to close anytime the bimetal choke coil is cold enough.

Adjust the choke linkage when the engine is cold to "almost" closed. Once the engine has run for a bit or the key has been on for a bit you will have to wait until it is all cold again.

 

[fishingman220]

Re: 2bbl carb problems

i will try that in the morning. thanks alot

 

[WizeOne]

Re: 2bbl carb problems

You didn't say what carb you have. Holley marine carbs do not have a fast idle cam, as the automotive versions do. As such, the choke plate closes, as things cool down, without having to open the throttle.

 

[fishingman220]

Re: 2bbl carb problems

i dont know what carb i have, all i know is its a 2bbl, and elec choke, and it is a pain to start, in the summer when its hot outside, it takes a good min or 2 of cranking, and pumping to get it started, once started, runs fine and restarts fine. any help????

 

[Don S]

Re: 2bbl carb problems

I suggest you find yourself a Merc dealer and get your boat fixed. Bondo gave you a link to the OEM service manual. Did you download it? If you can't ID your carb with that manual, then you really shouldn't be messing with it at all. It's the fuel system on an engine and you really don't sound like you have any mechanical experience at all, and I would really hate to see you get either you or your family hurt over trying to fix the fuel system (carb) and cause a fire due to leaks or whatever.

Don't want to see something like this from your next post.

 

[WizeOne]

Re: 2bbl carb problems

Ooh, that's hard Don!

 

[fishingman220]

Re: 2bbl carb problems

i am very mechanically inclined, i just do not know anything about carbs, i know that it is the fuel system, and i know how almost everything works except carbs, you dont have to dumb it down for me, i just seriously dont know anything about carbs, i have always messed with efi and that is just new to me

 

[Bondo]

Re: 2bbl carb problems

i am very mechanically inclined, i just do not know anything about carbs,

Ayuh,... So,.. Did you download the Manual,..??

It explains Everything you need to Know,.. With Pictures....

 

[fishingman220]

Re: 2bbl carb problems

the only thing i see for my boat is the front page and table of contents

 

[Don S]

Re: 2bbl carb problems

Obviously you never tried to use the link earlier, when it was first posted. Proves the old addage.
You can lead a horse to water, but you can't make him drink.

You must be looking at manual #17. You will have to open the first link, then scroll down to the outline and download each section seperatly. There are no blue or red, underlined links, just move your cursor and see it change over the links.

 

[fishingman220]

Re: 2bbl carb problems

i have opened the #17 manu. and then gone down to merc 2bbl and the mouse does change, but when i click on it it does nothing, i have a mac computer i dont know if that makes a diff