PPRuNe Forums - Cold mornings

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- - Cold mornings (https://www.pprune.org/private-flying/157654-cold-mornings.html)

The last few weeks have been particularly cold and as such I have had a bit of trouble turning over the engine to fire up. Trawling round pprune I found the following:

Quote:

With regard to that cold battery and engine, think about this. Fuel doesn't vaporise well in cold carbys, and a cold battery has less cranking power. The combination often means lots of frustrating cranking, and often flooding the carby, and flattening the battery.

Again - hot water to the rescue. Pour warm/hot water over the carby of your engine. It results fuel vaporising for a near instant start, and only requires a bit of uncowling in most a/c.

I've successfully used this on Cessna 152,170,180,182, and a Supercub. The 170 is a dream job - just slosh the water thru the aircooling 'hole' in the front of the enginecowl, which leads under the crankcase, and aft to the carby. It's been foolproof for over 10 years with my old bird.

Supposing external power is not available has anyone else tried this and if not what techniques do you use?

I'd want to make sure I didn't get any water on the ignition circuit though. In cars this is one of the biggest causes of failure to start in cold damp weather.

Which reminds me, where's my WD40...? :*

What engine is it that you are trying to start in the cold mornings?

I have a few tips for this problem but it would help if we knew what a/c, what engine and the method you are using that isn't working.

aircraft = pa28 cherokee 140
engine = standard lycoming
method = crank it, if it doesn't start after a few tries then give up

I used to have a 1967 Cherokee 160. I found that the battery flattened quite quickly apparently due to the electricity supply from the battery to the starter being made of the wrong metal or something (I believed the person who told me anyway!)

I found myself jump starting it frequently so tried several different methods and ended up doing the following.

Fuel on, prime twice, check mags off and turn prop through four compressions. Jump in, prime two more times, set throttle at about one inch, mags on, brakes on and turn it over. I found that even on -7 degree mornings it would normally fire with this method but do be quick with bringing the power back as the engine is trying to turn treacle at this point.

Good luck.

P.S If the a/c is kept outside it might be worth keeping the nose out of the direct overnight cold winds and perhaps even blocking the nostrils of the cowl the night before? This might stop the cold really taking hold.

Hope I've been of help.

If your PA28 is ederly it could still have the original aluminium cables connecting the battery to the starter. These are poor conductors at best and age adds corrosion to the problem. There is a mod to replace these cables with copper ones. We had this done to our PA28 and believe me it makes a hell of a difference, the engine spins round a treat on even the coldest of mornings, while before it struggled to turn through compression.