Walbro SDC question

[JonCraig]

The fuel pump side... this IPL shows a gasket, check valve diaphragm, and fuel pump diaphragm--part numbers 22, 25, and 24 respectively.

Because one is off the the side, I'm assuming that means you use either 25 or 24... not both, correct?

So how do I know which one to use, assuming that I don't trust whoever was in here before me?

Thanks in advance for the help!

--JC

 

[hotshot]

Correct, usually either callout 24 or 25, but not both unless both part numbers are listed.
If 24 is called out, and has the two "flappers", then 25 would be a backer gasket w/o flappers.

What's the SDC-XX carb # & the application?, as the saw service manuals do
occasionally show carb details LOL. If you look up the carb on Walbro's website, it
will only show a part number for the call outs the bill of material on the side bar,
meaning its for that specific carb, even though the picture is all inclusive/generic.

You can also match the fuel pump diphragm to the holes in the carb body, if the diaphragm is gone.

 

[JonCraig]

Looks like SDC-77, tho there's also a "1" stamped in it, too. Or maybe it's an SDC-1 that's from 1977?

Here's a pic:



And here's what might actually be my culprit. Seems to be called an accelerator pump. It's another pump diaphragm and gasket. I've never seen this before and was not in my genuine K10-SDC kit. Guess I'll have to go hunting for it, lol!

 

[HarleyT]

What saw is it off of? Are there any numbers on the side of the fuel inlet?

 

[JonCraig]

I can't see any numbers by the fuel inlet.

It's off a Homelite XL101.

 

[AVB]

According to IPL for the XL-101 it is a SDC-1. Item 25 not used just 24 (Walbro 95-21)

 

[hotshot]

Now you have the right info to work with. It's an easy find on Walbro's website, it's an SDC-1, first of the series.

Item 24 only, and the accelerator diaphragm part number 95-44 is there too. Yours is fricken smoked! I would call VE Petersen in the great state of Ohio, 1-800-537-6212, for that one.

If it's NLA, I would get ahold of Joyce who goes by the "chainsawlady". I can also send you a piece of the material to make one yourself, if it's close to .015" thickness. If it's thinner material, you'll have to find some or cut up another carb's diaphragm to make it

 

[AVB]

Or you could just the D10-SDC kit. Its one of those rare instances where the GND kit has it and fully carb kit doesn't.

 

[JonCraig]

Awesome--thank you guys so much!

Now--what's that thing do? (Don't say pumps fuel; gimme a more nerdy response)

 

[AVB]

But that what it actually does. Its a boost shot of fuel much like the 4 barrel Holleys did years ago. When it fails on those carbs there was one heck of flat spot in sudden acceleration needs. Those engine even died when you put your foot to floor board or at least it did on my Chrysler 300's 440 high performance engine.

 

[backhoelover]

i have the acc pumps need one