Carb problem but need wrenching expert

[Guest]

I have my carbs off and will be dipping them in cleaner. Unfortunately, I don't know what to do about carb #4. The mixture screw has a problem. The top 1/8 of an inch of the screw hole is shaved off and it looks like they dremeled into it to get or work on some type of plug? Well, check out the picture. Not sure how to go about fixing this or figuring out what to do next? New carbs, drill it out, leave it alone, any ideas?

[hikermikem]

Need a better pic, can't really see what it looks like... what are the other carbs like?? Is the factory plug removed?

[tom203]

The mixture screw got stuck and someone attempted ( or succeeded) in removing it and then replugged it.Can you see any brass? Compare it to other carbs and you can figure out how far down the mixture screw is. Drill out plug CAREFULLY and get at the screw.

[Mop Bucket]

I took some more pictures with a real camera. This is a comparison of both good and bad air flow screws. Tom, thanks again, after seeing more evidence do you still think I can drill it out? I am hesitant because I don't know what I am doing.

Good Screw




Bad Screw



Top comparison



Side comparison

[spyug]

Man that is too weird. Never seen that before. Looks like they tried to cut a bigger slot in the screw top possibly for more leverage to get a stuck screw out.

While it really should come out and be replaced, I think I'd be tempted to leave it and clean the carb as best I could without dipping (in case of destroying the o-ring on the airscrew).

The best solution would likely be to replace the carb set. I had a similar problem. One of my airscrews would not come out no how. I cleaned the other three properly but just "squirted" the last one. Ran them that way for a month or so until I was able to get a replacement set from another member.

That is a real pain in the patoot my friend.

Good luck with it and let us know what you decide to do.

cheers,
Spyug

[tkent02]

Is that the mixture screw or just a plug?
Can't tell from the pic. The screw should be a lot farther down in there, like the other pic. If it's just a plug, pull it out with a drill bit.

[hikermikem]

Is that the mixture screw or just a plug?
Can't tell from the pic. The screw should be a lot farther down in there, like the other pic. If it's just a plug, pull it out with a drill bit.

I'm with Tom, it almost appears that what's left is still the old factory plug ( they are about .200" or so thick).

Try to do some depth measurements between the two carbs & see if you can verify it's still just the alum plug (or what's left of it...).

In any event, it doesn't look like you've ruined the threads yet so all is not lost. If it's the plug, drill a small hole in it and thread in a small sheet metal screw & pull it out. Use the depth measurment from the good carb to judge how deep you can go before hitting the screw head (don't want to do that).

Good luck - certainly a weird one!

mike

[Nessism]

Looks like someone took a hack saw and took the top half of the tower off, then turned the hack saw and butchered a super wide slot into the mixture screw. I suggest getting a wide blade screwdriver, might have to grind one yourself if you have a grinder, and see if the screw turns. If not, use heat on the carb body, and some sort of pent. oil, before it will come out. After the screw is out you should be able to decide if you need a new carb body or just a mixture screw.

Good luck.

[posplayr]

looking at the forensic evidence (gee this is getting to be fun ), looks like what Ed described however by close inspection of the cut slot in the mixture screw you can see how it is rounded. The PO after cutting the slot did use a large flat head and was able to round the groove but not loosen the screw. He probably stopped at the point which was a probably the best move he made.

It looks like if after hear and penetrating oil I would just use a reverse LEFT HAND drill and get it out and put in a new replacement. Those threads have not seen the light of day in 30 years and after drilling and replacement a new mixture screw should work fine.

Of course if you come across a replacement carb now would be the Best time to swap it out.

[raistian77]

I would try a new carb first. That one is pretty jacked up. It looks like the mix screw that is cut up not the plug. If they cut the threads up bad a new screw may not thread in and you would have to resort to tapping the hole. 80+ CV carbs seem easier to find than the old VMs, get another one clean it and swap the guts in.

[Mop Bucket]

Glad we are all having fun

I think I will drill it and hope its a plug. The PO has done some questionable stuff so I am hoping its a plug. I will let you know what happens.

[tom203]

Glad we are all having fun

I think I will drill it and hope its a plug. The PO has done some questionable stuff so I am hoping its a plug. I will let you know what happens.

Yeah, why not! as mentioned try a left-handed drill bit carefully. The PO definitely had some novel approaches- what fun he has left you!

[Mop Bucket]

I have good news, bad news and noob news.

Good news is that right now I think the threads are ok. Most bolts or screws are stripped on my GS. The PO was all grip and rip. He needs an impact driver. My impact driver is my favorite tool now especially since I started working on the GS. I have loosened tones of screws I would have given up on without it.

Bad news is that I drilled a hole through the thingy in the picture, it is the mixture screw that has been butchered. Going to be tuff to get it out. I will try a left hand bit and screw extractor.

Noob news is that I didn't understand left handed drill at the time of the suggested and decided to drill anyways. On a good note, the bit jumped and is not centered in the screw. This helped me confirm it is the mixture screw and that the threads are probably good. I could see threads through the drill hole because of the large head and I drilled to the empty space after the head, if that makes sense.

So, if I can find my smaller screw extractor I will give that a try. If not... Shrug, drill a second or third hole, break the screw, or something. Other suggestions welcome.

[hikermikem]

Dip the carb body for 24hrs, then try to get the mixture screw out with a left handed bit... the dip may loosen up all the crud holding it in & make it easier to remove.

Screw extractors can be a PITA if you break it off in the scew - they are very hard & brittle.

Start looking for a new carb body just in case.

good luck

[old_chopper]

Dip overnight then rinse the carb thoroughly. As mentioned use some heat as the aluminum will expand and help free up the screw. Be very cautious with an extractor, you will not be able to drill a broken extractor out.