Ok, so as some of you may have read I ran into some problems attempting sterlings accelerator pump mod. I made an initial thread about it here:

https://www.rx7club.com/1st-generation-specific-1979-1985-18/question-sterling-anyone-else-who-has-done-ap-mod-their-carb-610194/

Taking Sterlings advice I went out and picked up a fresh new diaphragm:






Today I attempted to give it a bit of strech but was faced with the same issues as the 2 old diaphragms I had tried.

This time, however the harder shell that was on the diaphragm fell right off after i tried streching the diaphragms throw.





At this point I realized that there really is no way of getting enough throw with the hard shell on there to make the 3/32" added on each side worth even being there.

I decided that I am just going to have to forget it even had a shell piece on it and make do without. Here I have shown what I have left.

3- 1/32" gaskets on either side of the diaphragm (which no longer has the hard shell)




Now, my biggest worry is that Im gonna go way crazier than sterling intended by installing it like so, without the hard shells structure to limit its throw.



This way I can get all the throw that the gaskets permit, with only a small bit of wrinkling that should just get squished into the gaskets I cut. Now is this way more throw than on a sterling carb, or that sterling intended? I dont know but it really seems overboard. I have tried so hard, but now I just dont know what to do.
Any help would be great.

 

bumperooni

 

bump for the man

 

I think you misunderstood my previous instructions regarding stretching out the diaphragm. What I meant was that when the carb is assembled, when the diaphragm gets worked back and forth, it will begin to stretch.
The other thing is that you have to study the linkage a bit, and you will see that the spring on the accelerator pump lever rod will be the only thing actually "pushing" on the diaphragm in the output stroke, and the only thing "pushing" on the diaphragm on the intake stroke will be the spring that sits behind it in the housing.
IMO, you're spending way too much time on this bit of it. Unfortunatley, I think that diaphragm may be hosed now. You might try to 'glue' it back onto the paper backing with some kind of sealant, but it really should have that support because I don't feel confident that the gasket material will keep it from pulling in as the edges, and then leaking.
If supported, over time it will stretch on it's own to a point.

 

ok, thanks for the help sterling.