flyrotary@lancaironline.net Mailing List Archive

Bill,

Today I spent some time in my plane trying all the permutations and combinations of applying power to the primary injectors, secondary injectors, and grounding EC2 pin 30 with the cold switch.

It turns out that my statement in the message below concerning the effect of grounding EC2 pin 30 when cutting power to the secondary injectors when the MAP is below the staging threshold MAP was not correct. When I did this today, the mixture went slightly richer just like you describe for your system.

As a result, my guess is that this behavior is most likely not an indication of a problem to be solved.

Steve Boese

From: Steven W. Boese
Sent: Monday, January 25, 2016 12:23 PM
To: Rotary motors in aircraft
Subject: Re: [FlyRotary] Re: parts upgrade; was: What do you think may be happening?

Bill,

Turning on the cold start switch is intended to give you a much richer mixture when both the primary and secondary injectors are enabled. So your system is working correctly in this regard.

Disabling the secondary injectors with the DPDT switch is intended to both cut the power to the secondary injectors and enable the cold start function (as if the cold switch was turned on). This should have no effect on the engine at MAP below the staging threshold since the engine would be running on only the primary injectors just like it was before flipping the secondary disable switch.

Your previous statement:

"With the engine idling at about 1400 rpm, and the mixture at about 14.7, I turned off the secondary and the engine ran a little differently and the mixture went to about 13.0."

is troubling since doing this should have had no effect whatsoever. Is the mixture change persistent and reproducible? If the mixture eventually (within a few seconds) returns to the original value, then your system is most likely working correctly in this regard too.

Steve Boese