Cold Weather Ops

[Dave S]

Hi Dick,

Like to think I am pretty good at freezing my tochous off trying to start things with gasoline engines up here

So here goes.

First off, I don't know that everyone has the same concept of "cold"

1) Anything down to 32-35 degrees F I do not preheat......a) do the rotax burp, b) close the throttle to the stops and then open it approximately 1/4 turn on the vernier (not much at all in case you are not using a vernier throttle....in any case, just enough to get it off the stops) c) Pull the choke & crank till it starts....usually starts right up within 2 -3 seconds. d) Modulate the choke for a few seconds, usually no more than 5 seconds when the temp is near freezing......if 50 or better, pretty much get off the choke right away e) adjust the throttle for 2000-2200 rpm to warm up.

2) Anthing colder than 32-35 F....I use a 1500 watt milk parlor electric heater rigged up with a plenum and 4" convoluted duct and plug that into the cowl below the prop. blanket on top of the cowl. Plug the side holes on each side of the prop and let that run for an hour +/- (if it's zero - runs an hour, if its 20-30 F run it half an hour to 45 minutes. After the preheat it starts like it would if 40-50 F outside).

I like to preheat when it is near freezing or colder just to be kind to the engine in the first place.

I have started the engine W/O preheat down to 15-20 F but it behaves much like you indicated (although I don't know what temp you are experiencing)

Any need to keep the choke out for quite a while after startup is not characteristic of my engine unless it is down to 15-20 F. With the preheat or warmer than freezing with no preheat...the choke does not need to be kept on hardly at all once it starts.

FYI - I have the rotax induction plenum installed with the air pickup in the NACA vent in front of the radiator - don't know if the induction plenum makes any difference on starting ot not....the airvalve provides an alternate air intake behind the engine but I start it on the normal cold air filtered intake in the NACA vent.

Sincerely,

Dave S
KF7 TRigear
912ULS, Warp Drive

[Slyfox]

this is what I have on mine. now I don't know what wattage I have, been to long. but I keep mine plugged in all the time. I go to fly, I unplug, fires right off. now the other day I didn't have it plugged in. was a little cold, like in the 30's and it farted and banged and broke my right side carb socket, oh and the throttle cable on the left side. learned my leason to keep it plugged in. it has a thermostate to shut it off when to a certain temp. you just need to read all the stuff. anyway this is what I have. I'm pretty sure I have the 150 watt.

http://www.reiffpreheat.com/Rotax912.htm

[DesertFox4]

The Reiff system is what John uses on the factory birds when pre-heating is needed.
My Arizona acclimated 912ULS does not enjoy starting much below 50 degrees. I do have the old style starter though and the newer high torque/speed starters might improve this.
There are days here that pre-heat on my particular engine would be beneficial. The Reiff system would be perfect. Problem at my over regulated airport is we can not leave anything plugged in and operating while not in the hangar. No heaters, appliances, tools, battery chargers ect.
Just the fridge.

[Dorsal]

Love my call ahead Aerotherm, call my plane a couple of hours before I fly and my oil temp is 90 at start.

[Dick B in KY]

Thanks for the replies, one and all. Seems like I'm going to have to get use to a cold natured engine and it's idiosyncrities, plus maybe install a heat system. By the way, my engine performs like this at any temp below about 65 degrees, must have something to do with the Kentucky air around here.

Dick B

[896tr]

Maybe give it a shot of Evan Williams.

[SkyPirate]

Hey Dick my engine starts really well in cold weather trade ya lol