1977 850 merc carbie (wm5) question

[wrxcobra]

Hi all I have a question that I hope someone can help me with; I am putting a carbie kit in a 1976-1977 850, 85 HP blueband merc.
I m not sure what you call it but in the main part of the carbie were the butterfly (disc) is that tilts as you give it power. There are some little holes. I was using a carbie cleaner to check that all the holes were not blocked up, and the holes at the middle there was no carbie cleaner coming out. It has three holes near the top in a triangle pattern smaller at the top and then they get bigger as they go down, they are fine. Then further down there are another two holes towards the side 90 deg, they are the ones that appear blocked. Then finally there is a larger hole even further down that is fine also. I hope this makes sense.
The engine has two carbie and they are both the same (holes blocked) are they meant to be open or are they for a larger motor (115 HP).
I know that I can pull out the Welsh plug and have a look but didn?t want to do that unless I really have to.
Can anyone help?

 

[Chris1956]

Re: 1977 850 merc carbie (wm5) question

Cobra, It sounds like you are trying to clean out the idle passage. If so, there is a brass tube on the outside of the butterfly. if you spray carb cleaner into it, it should exit thru those holes in the side of the carb throat. In addition, if you remove the idle sdjuatment needle and spray in its hole, the cleaner will come out those same holes. There is a small brass plug next to the adjustment needle. Remove it and spray the idle restrictor as well.

 

[wrxcobra]

Re: 1977 850 merc carbie (wm5) question

Chris, here is a photo of ( not actual carbie but the same) when i put carbie cleaner in hole C it comes out of three holes A near the top but not out of two holes B that are down further. It s the same on both carbies there is a larger hole even further down and it does come out of that hole also.

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[wrxcobra]

Re: 1977 850 merc carbie (wm5) question

I removed the need and set, idle adjustment needle, and anything else that looked easy to remove.
I sprayed the carbie cleaner in all the holes and passages every thing else looked fine, it was just these holes in the side of the carbie throat that were not working are these the are these the idle passage holes?
Are they meant to be open or not, like I said I know if I remove the Welsh plugs I can see if the are blocked with crap or meant to be blocked, but I really don?t want to take out the plugs.
and if they are meant to be open how do I clear them?
Thank you
Daniel

 

[wrxcobra]

Re: 1977 850 merc carbie (wm5) question

dont want to be a pain but if someone can help it would be great as i would like to get it going asap, I NEED TO GO FISHING.

 

[Chris1956]

Re: 1977 850 merc carbie (wm5) question

Daniel, Your photo would not resize, and it was a bit hard to see. Generally, all the carb passages can be blown out after removing the threaded brass covers. You should be able to leave the welsh plug alone.

That carb appears to be a little different than the ones on my '77 1500. I do not have holes c or B. A is where my idle jets are, and there is a tube and a hole on the choke side of the carb that feeds them air, allowing fuel-air mix to come out holes A.