Hi, I have a CRRC Pro GF26 (the older machined crankcase version).

Anyhow, it was running fine and then the top end started giving problems. At WOT, it would run erractically as if fuel feed is intermittent (but there do not appear to be any bubbles in the fuel line) and just wouldn't rev up. Idle and mid range seem to be ok. Thought there was a problem with the carb/HS circuit, so I cleaned it out and reset the needles, but the problem's still there.

I would like to eliminate the EI as a source of the problem. On hand, I have a SPE26 EI that I know is working for sure. Can I just hooked it up to test using the CRRC Pro sensor? I understand that the curves may not be optimised, but at least I'll be able to take the EI out of the equation.

If the SPE EI is ok to swap in, the next question would be how do I tell the polarity of the sensor? Or does the sensor have any polarity? Both EI units/sensors appear to have polarity specific connectors. Or would it be better just to stick with the matching sensor. (Which I'll have to remove from the SPE engine)

Thanks.