Starting troubles

[ChevyPete]

Hello all, I'm just new to this forum and I'm looking for some ideas/answers to help me get my truck running. I have a chevy 350 with a vff30 lock off and a model e impco vapourizer with a impco 425 mixer and the trouble I'm having is it seems like the vapourizer is not flowing fuel when the lock off is activated,(the lock off is functioning with both me sucking on the hose or cranking vacuum) I can get my truck to run for a few seconds if I hit the primer button but then it dies almost immediately, I'm not sure what else to try to keep this thing running any help would be appreciated

Thanks in advance

[Steptoe]

Is the converter new?
If not, is it one of the old ECI unit with the 2 square boxes on the front cover?
If not new, has all the oil/ grease crap been cleaned out inside?
The 'hook' that connects to the diaphragm at the corect height... 1/32" make a big difference
And are u 100% sure the diaphragm doesnt have a hole in it?

[ChevyPete]

Thanks for getting back to me, it does not have the eci setup I just got a rebuild kit for my model e today and I did set the height of the pin with a straight edge I also put two new diaphragms into the 425 mixer and I'm just about to try it so fingers crossed!

[Steptoe]

Over 200,000 miles , rand the unit was 2nd hand before I got it.. I have never had to replace a converter or mixer diaphragm... except the idle diaphragm on the side of the 425.. and that was my carelessness yrs ago winding the mixture screw in and out...
Just a lot of caution pulling covers and diaphragm edges off slowly... and torquing those screws down slowly and correctly

Hope all works for u

Have u had the unit running in the past?.