The check valve was gone completely? Yeah that would flood it i think.
Need some serious help on a finicky Mac 10-10
- Thread starter Gaspowered
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Gaspowered
ArboristSite Member
Yeah, when I took it apart nothing was in there. Do you know the size of the welch plug? I might have another one and I don't want to wait and get a new one.
Conquistador3
Le Comte de Frou Frou
Those SDC carburetors came with two welch plugs if I remember correctly: a 3/8" and a 5/16", both OD.
The 3/8" is a pretty common item (used on Tillotson, Zama etc), the 5/16" less so but t's still easy to find.
Gaspowered
ArboristSite Member
Yeah, they have 2 welch plugs. I think you can get assorted freeze plug/welch plug kits like the ones you see on water cooled outboards and other carburetors. Last night I took the carb off again and after learning that it does in fact use a check valve, I stamped one out roughly to size with a gasket punch and fuel pump material and unbelievably, it fit inside the little recess where it sits. I put it back together and it sorta ran. It stopped flooding, and it ran for about 3 more seconds. I don't have the one out of the kit, probably because I threw the kit and its unused parts in my toolbox and it went bye-bye. I bought two carbs off of eBay so i'll wait on those and see what happens. I actually took the carb off of my 6-10 Auto and it ran, but it was out of tune. There's no way i'm putting a working SDC on this saw so that's why I bought some spare carbs. I almost never mess with check valves but now I know. Only other ones i've seen use a little rubber "ball."
Gaspowered
ArboristSite Member
Well, found out what it was. I bought two carbs off eBay and built one good one, WITH a check valve, threw it on the saw, and started then stopped. At that point I ruled out the carb. I took the tank and handle apart, split the crankcase and the large flywheel end oil seal had a ton of sawdust and crap behind it, and where the sealant would have gone for the crankcase halves must have disintegrated, because there was nothing on the cylinder base and there was a puddle of gas in between the left part of the lower case. Simple induction leak. I ordered oil seals and I will use sealant on the halves.
Razor6niner
ArboristSite Lurker
I'm having Problems with an od ball right hand pull 10-10. Checking the impulse hole with carb removed. It seems to have never been drilled out in the handle or the cylinder. I thought it was clogged so in the handle I started with a tiny drill bit and metal started come up it has a walburo SDC 3 on it. I could drill the handle out but it makes no sense and if I have to drill the cylinder I'll end up with metal shavings in the cylinder which I do not want. And the two holes line up. So they don't turn like in the metal gasket. Any ideas?
The hole in the insulator under the carburetor does not line up with the hole in the cylinder, the insulator between the air box and the cylinder has a passage to align with the hole in the cylinder.
Mark
Mark
tom maslar
ArboristSite Lurker
100 compression is low. That's your issue. 150, 140-- that's good compression on a 10-10
