When I wrote vent tube I meant same as "hose". Welch plugs are sheet metal plugs that you remove with a tiny pick. The carb rebuild kit will usually include new welch plugs. You need to take them out before cleaning the carb because often there is dirt under them, and the cleaning fluid can't get in there to remove the crud if the plugs are still in place. There will be two plugs, one larger than the other. The carb kit should also include a new screen and retaining split ring. It's a good idea to remove that screen along with the welch plugs, that way all the small passages and holes in there get the carb cleaning fluid treatment. Tiny particles of dirt and sawdust can still get in these areas and build up, they are small enough to get past the fuel filter in the gas tank and build up into a deposit that can reduce or block fuel flow in the carb.
Crank seals aren't easy with the L65 points ignition crankshaft. On the flywheel side, there is a cam on the end of the crankshaft that is almost impossible to get the new seal to slide over without tearing up the seal. What I did was carefully cut some electricians tape to the width I needed, and I built up layers of tape on the crankshaft so the seal could slide over the obstruction. Down at the bottom, where the new seal will fit, there is a square "shoulder" on the shaft that the new seal will once again have to slide over in order to get to its final position. You'll have to put some tape in there as well so the seal can move down the shaft smoothly during installation. If you force it here, you can tear up the seal and have to start over. There is another similar shoulder on the clutch side of the crankshaft as well. I've included a pic here of what the flywheel side of the crank will look like with the obstructions on it you'll have to deal with during the new seal procedure. I had a tough time with mine getting the flywheel off, but I did it with some help from you tube videos showing various procedures to use. I was unable to figure out any way to use a puller on the L65 flywheel. With the Stihls I've done, I used a simple puller tool I bought on ebay that made it easy.
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