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I picked up this XL-500 from a fellow Homelite enthusiast in Oregon last month.He sent the saw with it's 24 in.bar & chain in a wooden crate that he made especially for this saw,the put the crate in a cardboard box.It was well made & well thought out.I fueled it up part way yesterday & put the bar & chain on & fired it up.The saw has a bit of a "bite" to it when pulling it over.It runs great & has fantastic compression.This is a 74cc engine on an XL-12 chassis.
 

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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:
IMG20240311112028.jpg
IMG20240311112042.jpg
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:
1000006880.jpg
Which I'm guessing is this:
1000006879.jpg

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).
 
sxl-123.

Don’t see them up here. But, the Terry 76/130’s were what we were offered. Hot rods when running well. About as strong a sub 60cc reed design I’ve ever run. Same piston as the sxl. Gobs of torque and good chain speed.



I see you have the SDC with the additional accelerator pump. I’ve only have one Terry equipped with that and it was a very early 76. All the others came with a Tillotson.
 
I've had this XL-12 for about a month now.I had a mishap with the coil/stator plate after cleaning it & ended up putting another coil/stator plate in it from an old blue & white SXL.Then I had to send the carb to Leon for him to fix because I couldn't get it to hold pressure after a rebuild.I got the carb back yesterday & installed it & I finished up on the saw today.It's a darn nice running saw!
 

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Yes it it, I replaced it with a worn out SEZ. I will go through it and give it a thorough cleaning and see if it can be made into a runner. In any case, it is likely to end up in the display.

Mark
Nice. It looks like it will clean up pretty good. I agree with @Hoggwood about these.
 
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).
I'd appreciate some help with this Super XL.

This saw is beyond frustrating. I had some cleanup work after a 70 foot piece of pine decided to split from the main trunk. Figured it would be a perfect time to finalize the tune and run this thing. Well, I had the same symptoms as last I described in the original post, but also developed some concerning things. Erratic idle, idling high coming down from WOT, shutting down when tilted down, racing when tilted sideways, and then at WOT it would come to about 9500-10k RPM, and suddenly race to 11K.

So I figured I must have a vacuum leak. So frustratingly (seriously taking the carb is huge PITA, curse those engineers), I took it apart AGAIN expecting a leak, and tested. Nada. Zilch. Passed with flying colors, and I even kept it pressurized/vacuumed over 30 minutes. Needle didn't budge at 10 or 5 psi pressure or 15 mmHg vacuum. I had it sealed between the reed valve and the carb, so it must be the carb, I think. But I changed the diaphragm in the pictures, and it passed a pressure test.

Could this be a bad check valve (it held vacuum when tested for what it's worth)? What other carb specific issues could cause these symptoms? Am I missing something?
 
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