Since the WX has started getting below 30 hand prop is becoming a chore. I have tried placing a small heater from walmart in the cowling and running it for 40 minutes and couldn't get it to start (OAT 5 degrees). I believe one fault i had with that was no blanket to cover the engine while running the heater and also possible not enough air flowing through it. any ideas for helping the preheat?

Secondly I have a C90 is there any tricks to getting it started when cold? I thought of hitting it with some ether in hopes that in would vaporize better then the 100LL. What I have been doing when about 30 is pulling the prop through 5 times after a shot of primmer mags hot and carb heat throttle cracked, pull another 5-6 times of no start mags off backwards 4 times forward 3 mag hot and usually 1-2 pulls it fires. From what I can tell the primer doesn't do much besides make fuel drip out?

GumpAir wrote:https://www.backcountrypilot.org/forum/makeshift-preheating-3124

And in addition to that one ^^, there's lots more!

https://www.google.com/search?aq=f&q=pr ... ypilot.org

cstolaircraft wrote:...Secondly I have a C90 is there any tricks to getting it started when cold?

Hand propping a King Air? Why? I know they have electrical systems and electric starters.

Sorry, couldn't resist. Yes, cover the entire engine cowl, all they way around. And if the prop is metal cover that as well, just a huge heatsink otherwise. Not familiar with the heater you are using but not sure 45 minutes is enough to get the core of the engine warm.

Cover the cowl with an old (or new) sleeping bag, then put the heat to it. Depending on the amount of heat, 40 minutes may or may not do the deed. Once it's heated, let it sit for a bit, covered....you want that heat to soak to the engine's core.

To start, I prime four to five shots, then mags hot, throttle cracked, and it'll fire every time on the third blade. If yours doesn't, have your mechanic check mag timing, impulse couplings, etc.

Are your impulse couplings firing? You should hear them snap when you pull it through. Most C 90s have two impulse couplings, but not all, so try a start with left mag only energized.

These engines should be easy, reliable starters.

MTV

Are you hangared and/or have electricity handy?
I used to cover the cowl with a blanket & hang a drop light with a 125W heat bulb under the engine of my C170 and C150/150 which did a pretty good job of keeping the engine luke-warm to the touch.
I put it under there when I came in from flying, so the engine never cooled way down. Once the engine is cold, it'd probably take a couple days for the heat lamp to do much good.

I'm unable to get the drop light under there with my 180, the cowl flaps are too small plus the mufflers & air box are in the way. I've tried the drop light through the oil door but putting the heat in from the side of the engine just doesn't work nearly as well as from below.

You can get an oil pan heater, I think you'd need to run it for at least a couple hours for it to do much good. Ditto any kind of forced air heat.

All good advice and I'll not repeat much. I flew a PA-11 with a C-90-8 year round for 14 years. Hand propping it down to -40F with pre-heat. Some things I learned:

Make sure you prime the cylinders (2 or more) and not the induction spider above the carb. Gets the gas where it does some good and not stuck to cool metal on the way to the combustion chambers. Stuck gas makes for a lean starting mixture.

Make sure your idle mixture is set to give you about +50 rpm rise at cutoff at cold temps. Ensures a rich fuel mixture in cold air.

Set your idle to about 700 rpm before propping. Mark the throttle or learn that position. Makes the engine catch and run faster than slow idle yet not too fast after it fires.

Use cold weather oil so the engine turn easily even with marginal preheat. Not an oil thread so it's your choice.

Make sure your ignition system is correct.

Preheat to normal temps like 70F throughout the engine including the inner parts. Pull the oil dipstick and note that the oil runs off like in summer.

If really cold tie the plane down and start it. Once warm, shut down and cover the engine again to let the heat soak through the engine. A restart should be easy even in the cold but will take less prime fuel.

Gary

Crack throttle less or none when cold, more when hot. You're probably doing that. I didn't always have a heater at Tohatchi but had access to my Guard unit's Herman Nelson heater at Santa Fe.

Gary is correct!! Be very carefull priming if it is not going to the cylinder!! It is a great way to have a runaway engine fire. Check your oil temp or shoot the block with a IR heat gun to see just how well your heating system is working. If you have slick mags I would check the internal timing. They are notorious for having intermittent and cold weather issues.
DENNY

Good point Denny about fires. I forgot to note that I carry a good size Halon extinguisher and kept it close when propping, especially before I had the primer outlet moved upstream to the cylinders. Had it happen once when I primed the induction spider too much and the engine fired but didn't start. A small backfire got to the foam Brackett air filter so I had to remove it before restarting.

Nasty business that gasoline. Aviation fuel doesn't want to fire as easily as winter blend auto fuel in a variety of equipment in my experience during cold.

I've also had a fuel injected C-185 fire in the exhaust outlet from too much prime. Noticed the orange colored flickering on the snow to the right of the plane on startup. Pulled the mixture off and kept cranking until it ran out of fuel. Smudged the cowl some but no permanent effects except a lesson learned.

Gary

Idle mixture was mentioned in a previous post and it is a factor.If it will only start with prime and then dies I would enrichen the idle mix and try it again.It does not take much adjustment to make a difference.

Bill

Just for grins!! I just received a couple of those dam TV add Handy heaters!!
350 watt, fan, has timer and thermostat!
Put a cover over the 310 engine (TIO-520) and stuffed it in the cowl flap! Temp in the Hangar is 40.
checked in 2 hours and temp on the crank, case, turbo, and everything I could shoot was at 69-70 degrees.
Was just a test but low powered heater takes awhile!
I have been looking for a slow even heater option rather than a burn it till it's hot enough!!
Should be able to keep them warm with 700 watts!!
Just a short test to see how they worked! 29.95 FREE SHIPPING HAHA!!

At the risk of repeating what's been said in the linked threads, the best solution is a Reiff or Tanis heater, which heats both the cylinders and the sump. Second best is a sump heater. Any of those should be run for a whole lot longer than 45 minutes; several hours works best.

If there's no electricity, then a Herman Nelson or some other hot air blower works (with the danger of cooking things inside the cowl, or even the cowl itself--but the average itty bitty Walmart special isn't going to do the job.

Cary

To the OP: Several here have discussed mixture. Does your C-90 even have a mixture control installed? Those engines with Stomberg carbs almost always have the mixture wired full rich, and some with the Marvel carbs do as well.

When I bought my 11 it was equipped with an MA-3 Marvel carb, with the mixture wired full rich. As soon as I got it home I installed a mixture control, and I'd do that again in a heartbeat.

If it had a Stromberg, I probably wouldn't bother.

MTV

So here's something I've been confused about.

Lots of people say "pre-heat and then let it sit a while to soak in". I get the soaking in part. What I don't get is, if you're going to be sitting there on the airstrip anyway, why wouldn't you keep applying heat?

Heating for an hour and then letting it sit for thirty minutes makes a lot less sense to me than heating it for 90 minutes and then firing up. Adjust times as necessary for heat source and OAT...

I agree with Marvel over Stromberg. I flew several different Stromberg equipped 65-90 HP Continentals before they started wiring them rich. It made no difference where the mixture was set. Same RPM, same fuel burn, same everything. I got to where I just left the mixture control alone. Also, most of those engines had no primer.That helped me learn how important the exact throttle position was in adjusting how rich the start mixture is.

Cstol put your tongue in the roof of your mouth and take a moderately strong breath. That is the sound you want. Huge breath, the sound of too rich. Normal breath, too lean. Keep pulling it through, with the mags Off, adjusting the throttle until you get the moderate breath slurping sound. The butterfly is your tongue.

The question was posed about heating longer versus heating and soaking. I agree that longer moderate heating is better, but only if components external to the engine core aren't overheated in the process...accessories, rubber mounts, hoses, electrical, fuel in the gascolator (can be seen boiling with a glass bowl), and the carb and its seals. Getting it all to normal room temps is the idea without excessive localized heat.

The reason I like to sometimes heat, start, run, then stop and let soak with the engine/prop covers on is to make sure after an hour or two of preheat the engine's internals are warm before applying normal full power (or even more in the cold dense air). If the preheat's longer then no need for any soak. But sometimes in mid-winter during short days at remote locations time is of the essence. The weather breaks or may get worse and we're trying to get going while pre-heating, breaking camp, loading, starting and flying without getting overheated and sweated up too much ourselves.

My indicator for a thorough pre-heat is to monitor oil temps after start-up. If they remain steady and increase I'll fly when the temp reaches recommended minimum for flight. If they drop due to the oil being cooled by internal engine components then it's either sit and wait for them to rise before leaving, or run a bit and let the heat from the cylinders and exhaust soak in while finishing chores. It's not a perfect method but it's been my drill.

Gary

Maybe it's worth asking the OP how cold it gets in Missouri?
Calif cold is different from Washington cold is different from Minnesota cold.

hotrod180 wrote:Maybe it's worth asking the OP how cold it gets in Missouri?
Calif cold is different from Washington cold is different from Minnesota cold.

He mentioned in his original post that the OAT was 5 degrees.

Absolutely nothing wrong with the Stromerg carbs on the A-65 through C-90 engines with the mixture. The issue is mechanics not knowing how the mixture work. The mixture plate and guts need to be in there to begin with, and the carburetor must be hermetically sealed. Very easy system and very easy to do by the maintenance book. The system works great out West when density altitude is higher, airports sit at 5,000 foot elevations and pretty much is a must. You won't see much with it at sea level airports of the East Coast as it really works good above 5,000 and up. I rebuilt mine in my 140 and I will tell you it works great. It's an old wives tale that they don't work, and I'm sick of hearing it.

The best way I pre heat is I put a ceramic heater in my cockpit and a fancy engine cylinder and oil tank heater at the engine STC. Put it on a timer so it kicks on 4 hrs before I head to preflight. Everything is nice and toasty. There is one guy that turns his on with his cellphone, he posted someplace I can't remember.