New carb socket fits loose

We will never find out, because there is no way I will proceed without resolving this. Every time I start wavering on that, I go stick one finger on it and rotate it to remind myself of how bad it is. 😀

Kelsie,

Now that you have established its the carburettor, not the manifold socket, it seems that your only course is to replace the carburettor - a good condition second hand unit?

A short term (not ideal) solution may be to shorten/reduce the spacer on the clamp, allowing it to tighten down on the carburettor.

I do not believe it is the carburetors. I measured the 1/3 carb (which is quite snug in its socket) and the 2/4 carb with a micrometer and got the same reading for both.

My current theory is that the drip tray or the manifold on the 2/4 side is not completely flat and its pulling the socket open a bit. The drip trays are fabricated from sheet aluminum according to Vans' kit assembly instructions, and there is some fuel tank sealant that goes between the main piece and a doubler that is attached to it. Maybe there is too much fuel tank sealant in there and its causing some bowing outward of the metal. Just a theory for now.

I’ve never seen one of these lose.
 Time  to trouble shoot.

Check the spacer on the clamp. It should be 7mm. Make sure the carb neck goes all the way in. There should only be about 1/4” between the carb body and the rubber edge of the socket. Sometimes these are hard to push in and take a little force to seat them all the ay in. You should feel the carb snap into place if pressed in far enough. Make sure the screw on the socket clamp bottoms out tight against the clamp spacer.

Just for grins measure both car throats outside diameter. Then measure both carb socket inside diameters. Both sets of measurements should be the same.

Hi Roger, I've done all of these things. At this point I believe I've ruled out the carbs themselves and the sockets. #1 suspect is the non-Rotax drip tray (as described in the RV-12 KAI - Engine Installation). I'll post back here when I make any progress or learn anything new.