So I have this SXLAO that I picked up a few months ago. It came to me running, but not well. Previous owner replaced the fuel line, filter, duckbill valve, and if I remember correctly, did a carb refresh. Since then I found the p+c was scored and the flywheel side seal failed a vacuum test (passed pressure interestingly). I swapped the p+c with an aftermarket set from Traverse Creek, changed the seal, and did my own carb kit.
I got it running yesterday but it idled erratically. Coming down from WOT it would get stuck at a high idle for a few seconds (enough that the clutch engaged), and then come down. It also raced when tilted to the flywheel side, and shut down tilted forward. After I changed the flywheel seal it passed a pressure and vac test so I was fairly certain it wasn't that, but sprayed some brake cleaner on both sides anyway. It didn't shut down with that. Then I thought maybe the fuel line is too short or leaking and it's sucking air, but both seemed fine. But I did find the carb wasn't holding pressure, a really slow leak existed, which is weird since it held when I installed my carb kit.
I thought maybe the inlet needle was leaking, but when I took the metering side apart the needle looked fine. I took apart the pump side, and found the pump diaphragm looking like this:
View attachment 1161174
View attachment 1161175
This diaphragm came from a brand new OEM carb kit from Zama, and after less than a tank of fuel through it. I run ethanol free VP fuel with Amsoil Saber at 40:1. Is this just a factory defect or did something cause this?
Now to my second question. The Zama IPL shows a "pump diaphragm retainer", on top of the diaphragm:
View attachment 1161178
Which I'm guessing is this:
View attachment 1161177
I don't see it being used in either the Homelite SXLAO IPL or service manual.
I just want to confirm that I don't need to use it and also to ask when these are used (I've seen them in carb kits for my other saws).