75 Mercury 850 Carb

[BOBBYC454]

Ok mercury gurus, need a little help. My project for this winter was rebuilding an 850 inline my dad had sitting around. All has went well until I've got into the carbs. They are the WMK-17, unfortunately I broke the idle air tube. I thought it wouldn't be difficult to find a replacement, boy was I wrong! In all the parts diagrams I have found, it is drawn, however doesn't have a referenced number. I'm pretty sure I'm going to have to find a whole used carb just to scavenge that part, but does anyone know where else I might try?

 

[Chris1956]

Re: 75 Mercury 850 Carb

It is likely that idle tube is cast into the carb body. You have sidebowl carbs right? I have a pair of them laying around from a '73 Merc 850. What part of the country are you in?

There may be a salvage yard around also.

 

[BOBBYC454]

Re: 75 Mercury 850 Carb

I'm located in Kentucky. Yes, they are the side bowl design, After I removed the plug screw the tube screwed in just like a jet, but is more nozzle like. One carb it came out easy, the other carb, well not so much lol Another question is, although its a wmk-17 carb, would the idle air tube from another wmk series carb be the same?

 

[Chris1956]

Re: 75 Mercury 850 Carb

That sounds like the idle restrictor tube. Is it totally destroyed, or just impossible to remove? Can you straighten it out? The part site I looked at didn't seem to sell the idle restrictor, so I cannot tell if there are different sizes. The idle on those motors is not real good anyhow. I would just get one from a salvage yard, as close to the same year as possible and install it.