3120XP carburetor Walbro WG6 VS. WG8 *asking the experts*

[Benwa]

Let me start this off by saying thank you to @Mastermind, @huskihl, & I'm sure there are others, for being willing to share your knowledge and experience with getting a high jet into these carbs. I know a lot of time, energy, & money have gone into getting them figured out and dialed in. It doesn't go over lightly on me. So sincerely, thank you.

Now, because I already have it, I'm doing this to a WG6. @davidwyby was nice enough to mark the location of the high jet ( +.020" lower per Randy) based off of his WG8 that already has a high jet. The WG6 doesn't have the factory existing "pilot hole" for location like the WG8. So, I've got all pertinent info I need to do this, thanks to the help of people previously listed.

WG8


WG6

 

[Benwa]

I've looked extensively at diagrams & parts lists and there is one thing with this carb I can not identify. I'm hoping those of you, "in the know," might be able to shed some light. The WG8 has a welch plug, where the WG6 has what looks like a jet possibly and a star washer to hold it in. I'm curious if you guys have seen this before. Is there supposed to be a welch plug here? Is this factory or has somebody been into it before? I can't find any info regarding it. Maybe I'm just not looking in the right places. At any rate, thanks in advance for any insight.

 

[Mastermind]

Let me start this off by saying thank you to @Mastermind, @huskihl, & I'm sure there are others, for being willing to share your knowledge and experience with getting a high jet into these carbs. I know a lot of time, energy, & money have gone into getting them figured out and dialed in. It doesn't go over lightly on me. So sincerely, thank you.

Now, because I already have it, I'm doing this to a WG6. @davidwyby was nice enough to mark the location of the high jet ( +.020" lower per Randy) based off of his WG8 that already has a high jet. The WG6 doesn't have the factory existing "pilot hole" for location like the WG8. So, I've got all pertinent info I need to do this, thanks to the help of people previously listed.

WG8
View attachment 314812

WG6
View attachment 314813

When I said .020 lower.....I meant toward the center of the carb. Not closer to the edge.

 

[Benwa]

When I said .020 lower.....I meant toward the center of the carb. Not closer to the edge.

@davidwyby marked everything for me referenced off of the WG8 he has. Then after talking with you, he did make another scribe mark .020" lower, closer to center of carb, that puts it in the proper location. Of course camera angles are wierd & it didn't show up in that picture, nor did I catch it. I was just trying to show that the WG6 didn't have the pilot hole. (I edited the post to a different picture, to avoid confusion on hole Location for anyone else) I also have your drawing that you so graciously shared with us. I will reference that and double check measurements when I get it.

Thank you for looking out. Again, thank you for all that you've shared previously & the input along the way as I go through this. Can't thank you enough.

 

[srcarr52]

The adjustable WG8 has all the high side fuel that is supplied to the nozzle going through the needle screw. Where the WG6 and other fixed jet carbs have a brass jet at the feeding the nozzle fuel. When modifying the fixed jet carbs the brass jet is either blocked off or reduced in size to limit the fuel supplied by it to make the needle less sensitive to adjustment. I usually solder them shut and drill a 0.025" hole. If you don't reduce the size of this jet your adjustable circuit will only add extra fuel on top of the stock amount, which in even very modified gas saws would leave you less than 1/4 turn out of the needle and even 1/16 of a turn makes a large difference in the turn.

 

[davidwyby]

@Mastermind should I be concerned about my '8 not having the channel you grind into it? Or if it works it works - besides the inconsistent 4 stroke? EC saws finger ported. I did notice the tip of my needle doesn't look perfect and it's very sensitive to adjustment. I might try another.

 

[Mastermind]

I've looked extensively at diagrams & parts lists and there is one thing with this carb I can not identify. I'm hoping those of you, "in the know," might be able to shed some light. The WG8 has a welch plug, where the WG6 has what looks like a jet possibly and a star washer to hold it in. I'm curious if you guys have seen this before. Is there supposed to be a welch plug here? Is this factory or has somebody been into it before? I can't find any info regarding it. Maybe I'm just not looking in the right places. At any rate, thanks in advance for any insight.
View attachment 314814

View attachment 314816

Someone has modified the WG-8 already. It had a screw in jet where that welch plug is.....and they added a hold to feed the low side too.

@Mastermind should I be concerned about my '8 not having the channel you grind into it? Or if it works it works - besides the inconsistent 4 stroke? EC saws finger ported. I did notice the tip of my needle doesn't look perfect and it's very sensitive to adjustment. I might try another.

If it works, it works. A blunt needle works better for me.

 

[Mastermind]

Also.....don't drill that low speed hole unless you block off the passage between the main nozzle and the low side.

 

[Benwa]

The adjustable WG8 has all the high side fuel that is supplied to the nozzle going through the needle screw. Where the WG6 and other fixed jet carbs have a brass jet at the feeding the nozzle fuel. When modifying the fixed jet carbs the brass jet is either blocked off or reduced in size to limit the fuel supplied by it to make the needle less sensitive to adjustment. I usually solder them shut and drill a 0.025" hole. If you don't reduce the size of this jet your adjustable circuit will only add extra fuel on top of the stock amount, which in even very modified gas saws would leave you less than 1/4 turn out of the needle and even 1/16 of a turn makes a large difference in the turn.

You guys are the best. It all makes total sense. Thank you for being so patient. Do you redrill the main jet .025 even on a stock saw or just when ported?

 

[Benwa]

Also.....don't drill that low speed hole unless you block off the passage between the main nozzle and the low side.

10-4. Thanks to all your help, all the information "clicks" now. Much appreciated, it means the world to me.

 

[srcarr52]

You guys are the best. It all makes total sense. Thank you for being so patient. Do you redrill the main jet .025 even on a stock saw or just when ported?

I redrill to 0.025" on a muffler modded or ported saw, it would probably be fine even for a stock muffler but who wants one of those?

 

[Benwa]

I redrill to 0.025" on a muffler modded or ported saw, it would probably be fine even for a stock muffler but who wants one of those?

Not me, that's for damn sure! Wide f%@%in' open! Haha

Thank you