Cold Weather Starting Difficulty

[Gary 40274]

Originally Posted by LettersFromFlyoverCountry

One trick that works well for me. After you try starting a few times (with a normal start routine and normal priming), just wait.... sit tight for about a minute... then try again.

I can't explain why this works (for me), but it works (for me)

Body heat and prayer

Gary

[LettersFromFlyoverCountry]

The words coming out of my mouth in those situations would never be described as "prayer".

[Flyingleap]

You know, the mag switch might be wired up "L" "R" in the wrong positions.
When you start it grounds the left mag. Just a thought...

[Mike Coady]

I installed a primer solenoid system from vans catalog. When it's really cold, I use it and it works well. I use it when temps are below freezing. This I believe is better than pumping the throttle. The front two cylinders on my O360 are the ones being primed. Marvel carb installed. Starts about like most other planes. All planes seem to have their own way. Just remember, too much fuel can be a problem. The solenoid is fitted/plumbed just past the gascolator on the firewall and is switched on/open, then run your boost pump several seconds to inject raw fuel to the front cylinders. Shut off solenoid and crank engine. Mine will start normally after a couple blades on the crank cycle.

[AndyRV7]

I have the same problem. It was bothering me more until this thread. I learned a thing or two here.

My first winter with the 0-375. It cold and hot starts quickly in the warm weather. But recently, it has given me trouble. I typically fuel with a single stroke of the throttle and then set the throttle about at the 1000 rpm position. Now, when it won't fire up, I don't know what to do. Typically, a little more advance on the throttle. That usually doesn't help so in fear of flooding the engine I pull the throttle back and try a quick shot with the primer. After that doesn't work, I shut it down and give the starter a rest. If I am lucky, the next go around will get it to fire, but twice I've had to get out and recharge the battery.

One thing I did notice this weekend is just how much more robustly the starter turned the prop with a full charge on the battery. That seemed to fire the engine right over but it may just have been the fact that I had already tried for a while. My gut feeling is that the battery had a lot to do with it. I try to fly my plane every weekend but it had been 5 weekends since I had a chance to start the engine this weekend. The battery still had enough power to turn the prop, but you could tell it was struggling. Even on successive weekends, the battery is not typically as strong as it was after a charge yesterday.

I am going to work the closed throttle start position into my procedure and see if that helps. I hate to use the primer though because I worry about wearing on the cylinder wall from the fuel. Also, I am never sure if it works like the rear wiper washer on my car...takes a few seconds to start flowing. I am never sure how much fuel I just injected into the cylinder. A frustrating process for sure. But I am glad to see we are not the only ones with this issue. For what it's worth, I preheat the engine with forced hot air for a good 1/2 to full hour. I still have all the issues above.

[JonJay]

In light of recent chats about spark plugs, by chance, are you using Champion plugs? Long shot....

[AndyRV7]

Interesting read. And another thing I have to worry about now.

[Doug]

I have had good results by completely closing the throttle during start. But the pre-requisite is that the carby's fuel bowl has fuel, so I run the electric pump for 20-30 seconds before and during start.

Also, consider pumping the throttle empties the fuel bowl.

I believe that the idle enrichment circuit works best when the butterfly valve is closed. Note the small hole in the side of the carby throat above the throttle plate is where the enrichment circuit emits the fuel (and air) mix. If the throttle is opened then there is insufficient pressure differential to get the fuel flowing through this secondary circuit plus the ventruri & main jet has insufficient airflow to draw fuel to start the engine.

I have no primer on my engine and rarely need to pump the throttle. This is on an O-320, not sure if the larger caby has the same features.

[AndyRV7]

One throttle stroke and back to closed and she started right up. And without that hi rpm burst from the extra fuel. Great tip. Thanks. Andy

[Smilin' Jack]

I am running an IO 360 in my RV so the follow is from what we use on a friends RV6, C 172 and a few others when it gets into the 20.

We preheat... Not a fancy preheater but one of those ceramic heaters which we fit with duct work from the aviation dept of Home dept. Usually for an hour.

The next step is one you might not do... but if you check the mags grounding out at idle rpm you have a pretty good confidence that with the mags off and the key hanging up.. we pull the prop through about 10 revolutions... ( If you do not check your mags grounding on a daily basis do not do this until you know your mags ground out with the key off.)
Use the same technique you would if you were propping the engine except
Mags. Off, Fuel OFF, Mixture idle cutoff, and throttle to idle and someone on brakes.

Starting.
Mixture rich, 3 pumps of the primer, we generally leave it out,
Throttle 1/4 open or less. Clear and engage starter. If the engine sputters
we slowly advance the primer. We do not pump the throttle...
99 percent of the time the engine just starts fine...let the engine idle near 800 rpm until the oil pressure comes up and the oil temp start to move. Don't get in a hurry.

Like I said.... as far as pulling the prop through I have done this most of my 45 years of flying in cold weather instructing in Angola Indiana or Ohio. Before I came down south. On radial engines I flew we had to pull the props every first start of a day... Assume the engine can fire and start.. so take precautions...

I see more damage done to engines by folks starting even in warm weather when they start and the engine revs up to about 2000 rpm instantly and blows everything and everyone around... and they start taxing almost immediately... a extra minute or two at idle will be pleasing to your engine.

Jack