Small Aisan carb leak - odd place?

[Last Flight Out]

Had my factory carb rebuilt by a reputable shop here in Atlanta, but I’m experiencing now a very small collection of what I believe is just fuel and grime - it’s only around these two bolts/plugs and not coming from fuel window or under the carb. Everything else is dry except in this area and below on heat plate.

I’m just trying to understand what these two bolts are and if anyone thinks that the O-rings or crush washers may not have been done correctly. I’m not sure what the torque spec is on these two bolts and if I can pull these out and replace the O-ring behind them without too much fuss. Marked them with paint pen last year to see if they simply are working loose.

Also been watching @Pin_Head ‘s amazing carb videos and he did show these in his rebuild.

 

[vfrer]

Those are access holes for the jets. The bolts use copper washers that do need to be replaced during a rebuild. Can easily replace them but just be ready for some gas to come out when you remove them.

 

[CloudForestCruise]

Looks like it might be coming from the site bowl. There is an o-ring that hardens. If the rebuilder didn't replace it, that could be the culprit. Also, if @vfrer is correct, and the copper washers are leaking, you can re-anneal them by heating them with a torch till they glow and letting them cool.

 

[Last Flight Out]

Thanks guys - the site glass is not leaking and dry under. Not sure on the size of the copper washers....maybe same as clutch slave? Just need to find MUD vendor that can sell me both site glass gasket as well as those two brass washers. Or match them up at local NAPA etc.

 

[Last Flight Out]

Anyone know the torque specs on those bolt/plugs?

 

[charliemeyer007]

The screw heads on the the bat window look 1/2 stripped - a good shop would have replaced them

 

[charliemeyer007]

You want copper washers. Heat old ones, if not to mangled, to red heat in propane torch, air cool is fine. You can make that gasket easy enough.

 

[Last Flight Out]

Those are access holes for the jets. The bolts use copper washers that do need to be replaced during a rebuild. Can easily replace them but just be ready for some gas to come out when you remove them.

Shouldn't be too much fuel, right? Assume its just some fuel that is sitting at the bottom of the bowl/chamber?

 

[rlong]

The volume equals one “full” fuel bowl (less what it leaks), I usually catch in a disposable drink cup etc. I don’t think there is a torque spec; tighten them up till it resists against the copper washer and just a tiny bit more. Inspect the fuel bowl sealing surface and the bolts to make sure there’s no scratches or ridges that might impact sealing.

 

[bhsdriller]

Both the sight glass o-ring and those copper gaskets should come with a rebuild kit. Reputable shop would have changed those...

Did they use that yellow marker? If so looks like they were at least removed but could have just taken out to pull the jets

 

[Last Flight Out]

Both the sight glass o-ring and those copper gaskets should come with a rebuild kit. Reputable shop would have changed those...

Did they use that yellow marker? If so looks like they were at least removed but could have just taken out to pull the jets

No I marked with yellow marker to see last year if the boots were coming loose.

 

[mattressking]

Just remove the drain bolts (14mm) inspect gasket, if clean and not damaged, reinstall and tighten. There isn't a torque spec for it, just snug so it doesn't leak, I've done about 600 of those and they only leak if they aren't snug or the gasket is damaged.

 

[Last Flight Out]

Just remove the drain bolts (14mm) inspect gasket, if clean and not damaged, reinstall and tighten. There isn't a torque spec for it, just snug so it doesn't leak, I've done about 600 of those and they only leak if they aren't snug or the gasket is damaged.

Thanks bud. Clear and simple. Exactly what I was looking for.

 

[Last Flight Out]

OK once again thanks to everybody for chiming in and here’s a small update for today.

Clearly, these bolts were somewhat loose and didn’t require much from a socket to get them going so that to me might be the problem I was having. Turns out the crush washers themselves are actually a nylon or a plastic material and not brass so I wasn’t going to heat them up.

I wiped them down, checked them over for any damage (bolts and washers) flipped the washers over for a better seal and then tightened back down a bit more than where they were. I didn’t want to overdo it because these seem like just very delicate bolts/washers - maybe I used 10-18 foot pounds on them or less.

If leak persists, will replace crush washers an then the sight glass seal.

 

[65swb45]

OK once again thanks to everybody for chiming in and here’s a small update for today.

Clearly, these bolts were somewhat loose and didn’t require much from a socket to get them going so that to me might be the problem I was having. Turns out the crush washers themselves are actually a nylon or a plastic material and not brass so I wasn’t going to heat them up.

I wiped them down, checked them over for any damage (bolts and washers) flipped the washers over for a better seal and then tightened back down a bit more than where they were. I didn’t want to overdo it because these seem like just very delicate bolts/washers - maybe I used 10-18 foot pounds on them or less.

If leak persists, will replace crush washers an then the sight glass seal.

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Those look like the ones in the Standard 791 kit everyone on the forum likes to recommend. Never particularly liked them myself. Even the aluminum ones in the Keyster kit are better IMO.

 

[Last Flight Out]

Those look like the ones in the Standard 791 kit everyone on the forum likes to recommend. Never particularly liked them myself. Even the aluminum ones in the Keyster kit are better IMO.

Yeah they are fairly delicate an can see you don’t want to torque these down too much. Would prefer something more “stout”