It's Alive!

[Cess32cw]

Big day yesterday as I started my CAMit 3300 with the Bing carb for the first time. I am using a one gallon gas can as the main tank has not been installed. It fired right up and ran like a top. That is until I turned off the aux pump. After 30 seconds it died and would only restart with the aux pump on. Obviously something going on with my mechanical pump I would think. A little background: when the engine was delivered the crate was damaged and a nipple on the mechanical pump was slightly bent. Jack at CAMit said that he had an extra one and offered to trade it out at OSH. I removed the original pump, traded for the replacement and installed when I returned from OSH. Now a year and a half later I run the engine for the first time and this issue arises. I am guessing that it is an error on my part but thought that I would put this out to the group before I start taking things apart. Has anyone else had any issues with the mechanical pump or any experience reinstalling a pump that had been removed? Would head pressure have anything to do with this?

[Rick524]

Congratulations on the first start, its a big milestone! Is your fuel tank above the mechanical pump? I think it
needs some head pressure to get primed and start pumping. Hopefully you put the plunger and the spacer in
when you mounted the new pump? Don't ask me why I'm saying this, lol.


Rick

[DCASonex]

Early Camit engines (mine is #0004) were supplied with very weak springs in the mechanical fuel pump, intended to ovoid over pressure with tank in high wing planes which are what Ian bent had most experience with. For a Sonex you need the spring that Jabiru's use. ( I was in the air on first flight when found this out.) With many folks using AeroCarbs, would bet someone on this forum will have a stock Jabiru pump lying about that you can get cheap, and then when you find another spring, you will have a spare pump. If your CAMit is a later one, the pumps spring is probably not be the problem , and should check its mechanical actuation.

David A.

[Cess32cw]

Thanks David. My engine was the last one delivered to my knowledge. I will pull it off this weekend and see if anything looks suspicious.

[sonex892.]

Can check fuel flow by disconnecting the fuel inlet to the carb, then measure and time the fuel whilst winding the motor with the starter. In fact its the only way I know of, to verify the fuel flow of the mechanical pump.