SteveSr
Addicted to ArboristSite
Tom,
Good video with a couple of caveats for the uninitiated...
1. Walbro fuel elbows, especially the white ones, are known to crack and leak. They are NOT made to snap-on and off or rotate for that matter. However, cracked/leaking ones can be replaced. They are press-fit in and the brass stub can be removed with a pair of vice-grips. I use a drill press to press in a new one.
2. Main nozzle check valves can stick and leak. I have had much more issues with Zama than Walbro. Luis (retired from Walbro) recommends always pulling them out from the metering chamber side to preserve the soft aluminum bore (and seal for the new one) in the carb body. Walbro has a slide hammer in their repair kit for this purpose.
3. Avoid removing welch plugs unless it can be proven that the passages beneath are clogged. Re-sealing a new one can be problematic. Even the factory can't do it consistently with their high-dollar custom tooling. They resort to a proprietary secondary sealing material, likely some kind of filled cyanoacrylate. I have found older Pre-E gas carbs with the (green) factory sealing material flaking off in the metering chamber, likely due to ethanol gas.
4. Sealing main nozzles and welch plugs can be problematic as nail polish, seal-all, and similar products are NOT at all resistant to ethanol and will quickly disintegrate. Even non-E gas can still have a small percentage of ethanol in it. One brand in the U.S. had 0.5% listed on one of their non-E pumps. I have successfully used water thin cyanoacrylic (super glue) but you need to let it cure for a couple of days before reassembly.
Good video with a couple of caveats for the uninitiated...
1. Walbro fuel elbows, especially the white ones, are known to crack and leak. They are NOT made to snap-on and off or rotate for that matter. However, cracked/leaking ones can be replaced. They are press-fit in and the brass stub can be removed with a pair of vice-grips. I use a drill press to press in a new one.
2. Main nozzle check valves can stick and leak. I have had much more issues with Zama than Walbro. Luis (retired from Walbro) recommends always pulling them out from the metering chamber side to preserve the soft aluminum bore (and seal for the new one) in the carb body. Walbro has a slide hammer in their repair kit for this purpose.
3. Avoid removing welch plugs unless it can be proven that the passages beneath are clogged. Re-sealing a new one can be problematic. Even the factory can't do it consistently with their high-dollar custom tooling. They resort to a proprietary secondary sealing material, likely some kind of filled cyanoacrylate. I have found older Pre-E gas carbs with the (green) factory sealing material flaking off in the metering chamber, likely due to ethanol gas.
4. Sealing main nozzles and welch plugs can be problematic as nail polish, seal-all, and similar products are NOT at all resistant to ethanol and will quickly disintegrate. Even non-E gas can still have a small percentage of ethanol in it. One brand in the U.S. had 0.5% listed on one of their non-E pumps. I have successfully used water thin cyanoacrylic (super glue) but you need to let it cure for a couple of days before reassembly.
nice to be able to help others out as I have been myself over the years.
