3.5 hp diaphragm carb rebuild questions

[longlongtimeago]

Today I attempted to rebuild the original diaphrarm carb on my 1970 Rupp scrambler.

I ran into a couple questions..

I removed the carb with the intake manifold still attached and noticed there was no gasket between the manifold and the block...is that right?

Second question, the diaphragm I am replacing had no gasket [or it was part of the diaphragm] the kit supplied a gasket as well as the diaphragm, where does it go? above or below the diaphragm?

Third issue, the new needle and seat was different that the one in the carb. I installed it anyway and found that the needle never seated. Fuel poured right thru it. I can reinstall the original so that isn't a giant issue but can one of you guys point me in the right directions on the gasket questions? Thanks, Jim

 

[Minimichael]

Not knowing any particulars about the rupp set up, I'll venture these guesses: I would use a gasket at the manifold/block; the carb gasket position over/under diaphram might depend on 4-stroke vs 2-stroke (I wanna say where 2-stroke fuel requires more room on exit/venturi side of diaphragm?); and, ya gotta find correct screw or put old one back.
My two cents.

 

[creia]

Yes, there MUST be a separate gasket in addition to the diaphragm. As far as which order it is installed depends on which diaphragm carb you have. Do you have the Tecumseh service manual? If not (suspected) go back to the Tecumseh home page on this forum and download/view it for free- it is provided as a link the third post from the top. Page 23 will educate you on how to determine which way the gasket goes. Yes, there should be a gasket between the intake manifold and the block. It sounds like you have the wrong rebuild kit for your carb if the needle and seat are incorrect.
Michael