Mercury carburetor question..

[darin99]

Hi guys, I have a 1990 mercury 90 horse 3 cylinder outboard. I was wondering if somebody could tell me what the piece is on the carb of the picture that I attached called? The piece runs right in the middle of the carb, and goes from the mixing chamber down to the bottom. Dumb me thought the piece was cracked, so I took it out of the carb, and when I went to put it back in I butchered the bottom of it up. I had to cut just a tad bit of it off, but it is back open up now. What exactly does this piece do?

Sorry for the dumb question, but I didn't know if I would be ok keeping it in the way it is now. I'd hate to have to buy a carb for just that one little piece. Any help would be appreciated. Thanks

 

[merc850]

Re: Mercury carburetor question..

That looks like the idle tube, does it screw into the top?

 

[flyinbryan]

Re: Mercury carburetor question..

it looks like the fuel stem.

is it from a wme carb? was it press fitted?

i think its the fuel stem. it goes down into the chamber of the carb where fuel is drawn in through the high speed main jet.

this is all assuming its the wme carb. mine are pressed in and are not removable (nor would i ever need to)

im no expert but there are a few here that truly are that you will hear from im sure.

 

[darin99]

Re: Mercury carburetor question..

Sorry about that, I should have given a better photo of what I was talking about.

 

[flyinbryan]

Re: Mercury carburetor question..

yep, i think that is the idle tube like merc850 suggested.

how did you get it out? is it pressed in?

 

[merc850]

Re: Mercury carburetor question..

Before you try to run it with that installed I would check to see if a factory replacement is available. If not you could try a boat engine wrecker, I think it might make your engine hard to tune or worse, being damaged like it is.

 

[darin99]

Re: Mercury carburetor question..

Thanks for the info guys. Yeah I don't have any boat salvage yards around here really though, can't seem to find a carb like that. It shouldn't be that hard, I just don't know where to look at. I don't think you can get a replacement for that part, you have to buy the whole carb I believe.

If you guys know of any good online boat salvage yards or anything like that where I can check, I would appreciate it. Thanks

 

[Solomon Shaffer]

Re: Mercury carburetor question..

That looks like the idle tube to me...
My manual says that you can remove them, but when I pulled my carb apart I couldn't get the screw-cap to come out....so I left it in there.
What exactly DOES the idle tube do, anyways?

 

[darin99]

Re: Mercury carburetor question..

Ok guys, just wondering something here.

I have a set of late 80's 75 hp mercury carbs with the same casting # as my 1990 90 horse carbs. Maybe a question for you carb experts, do you think the stem out of those carbs would work in my 90 horse? I noticed the 75 horse stem was a little longer and goes down farther, but didn't know if that mattered or not.

Having a hard time coming up with a 90 horse 1990 carb, so needing to figure something out that would work.

 

[Bradmph]

Re: Mercury carburetor question..

Have a machine shop in your area? maybe they can make one or modify one for you? just a thought.