tecumseh carb with plastic main jet and orings

[38racing]

I was wondering what performance is affected if the oring(s) need replaced. I have a snowblower carb which is surging a bit on full noload rpm. A bit of choke improves it. I have only cleaned the bowl nut holes and the fixed idle jet. And did a run on seafoam. I am now going to check/clean the part of idle circuit in the centre leg and at the throttle plate edge. I don't usually remove the welch plug or the main jet. Not sure how often orings get damaged in main jet removal.

[bgsengine]

Part number 632547 you will need two each and they are *always* replaced (one on each end of the nozzle) - Often enough they are already falling apart and you'll find flakes of rubber , if not entirely turned into almost liquid - they will be damaged when removing them and they'll be almost impossible to re-install afterwards. Also, the nozzles are cheap enough, may as well replace that too (usually they are just a buck or two) - and the plastic nozzles are easily cracked or broken trying to get them out so you might just want to have a replacement handy anyway.

[Skywatcher]

Hi 38

Life of the O-rings depends on the type and quality of the fuel being used and how long the fuel has been sitting in the carburetor. The surging you describe either indicates a restriction in the low speed circuit or an air leak between the carburetor and the intake port of the engine. If the carburetor is still on the machine, a quick back flush of the idle circuit is often all it takes to cure this problem. remove the bowl nut so the crap can exit the carburetor. Next, remove the idle, pilot or low speed jet and insert the straw of a can of carb cleaner as far as possible into the hole and back flush the passage way in the center post.

If the carburetor is already off the unit, removing and checking the O-rings is usually easy. With the bowl nut off, the bowl and float removed and the carburetor separated from the intake elbow, take a small flat blade screw driver and gently press the plastic nozzle down into the center post. You may need to make a special tool from a length of 1/8" acetylene filler rod to get the nozzle the rest of the way out. To make the tool, grind the end of the rod flat then round off the edge. Now make a 90º bend about 3/8" from the cleaned end and cut the rod to about 6" total length so you have enough to hold onto without the tool being awkwardly long.

Once the nozzle has been pushed down to flush with the venturi, use the bent end of the tool to push the nozzle far enough so you can get ahold of the bottom end. The upper O-ring will usually stay in the carburetor housing but can easily be extracted using an O-ring pick unless it has gone to mush due to old fuel. Hope this helps,

Sky

[38racing]

Finally got back to this. I removed carb and sprayed carb cleaner into rest of idle passages. Good flow from fixed jet port to hole in the centre post. When I first restarted it the surging at full speed was actually worse. But then I set it to lower rpm and it ran good. I went back to full rpm and it ran fine. At least for a few minutes test run. Hoping it is going to stay that way. I am now taking auger box off to clean up and repaint some rusting areas. I did order some o-rings and nozzles.

[Mek-a-nik]

I guess we're talking about the emulsion tube and its o-rings?
Tecumseh 632760B is a carb kit that I use for a lot of Tec carbs. It has the o-rings and they aren't used all the time. I keep them for when I need an extra or two.
I've run into several different emulsion tubes. When I come across one I don't have, I order one in, as said, they're cheap.

[38racing]

I guess we're talking about the emulsion tube and its o-rings?
Tecumseh 632760B is a carb kit that I use for a lot of Tec carbs. It has the o-rings and they aren't used all the time. I keep them for when I need an extra or two.
I've run into several different emulsion tubes. When I come across one I don't have, I order one in, as said, they're cheap.

Thanks for the reminder. I may have one of those kits in stuff.