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Buckaroo

Won’t start??

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What is taking place when you ice the ignition module? It seems to me if icing it and it starts means a bad module than what happens in flight if it fails? I thought everything had a redundancy as backup?

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The starting circuit is separate from the normal running circuit. They don't fail in flight. If the ice trick works you are right about buying new modules.

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9 minutes ago, Roger Lee said:

The starting circuit is separate from the normal running circuit. They don't fail in flight. If the ice trick works you are right about buying new modules.

That’s good to know! What do new modules cost?

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4 hours ago, Buckaroo said:

I’m thinking with my Tannis on full time and the airplane sitting in a very cold hanger with temps in the 10’s etc. created the perfect storm for condensation. I can picture the carbs condensating from the heat beneath and very low temps on top. I probably have lots of water in the bowls. I’ll know tomorrow. 

You shouldn't leave it plugged in 24/7. Rotax are a lot less susceptible to corrosion, but there's still steel parts.

Put a couple gallons of avgas in, open the gascolator, discard the first sample, make sure the rest look good (they should not be cloudy and you shouldn't be seeing water), and keep draining until you smell the avgas. It shouldn't take long. Close the gascolator Filter and readd to tank if you want.

Pop a carb bowl, suck the fluid out and keep doing this until you smell avgas. DISCARD ALL OF THAT FLUID. Reassemble and pop the other one, this one won't take as long.

Now try to start.

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29 minutes ago, procharger said:

Don't you guys think he should see if it is firing first?

Back when I did Rotax training it was suggested that you not do as you described in your earlier post. You risk damaging the ignition module internally if you happen to not have the sparkplug grounded well.

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Great recommendations THANKS! 

Im curious no one mentions the fuel pump. How does the fuel pump enter into won’t start equation?

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It will start without the fuel pump.

As procharger was pointing out, checking to see if it's firing is a good idea too. However, use a timing light to do it.

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1 hour ago, Anticept said:

You shouldn't leave it plugged in 24/7. Rotax are a lot less susceptible to corrosion, but there's still steel parts.

Put a couple gallons of avgas in, open the gascolator, discard the first sample, make sure the rest look good (they should not be cloudy and you shouldn't be seeing water), and keep draining until you smell the avgas. It shouldn't take long. Close the gascolator Filter and readd to tank if you want.

Pop a carb bowl, suck the fluid out and keep doing this until you smell avgas. DISCARD ALL OF THAT FLUID. Reassemble and pop the other one, this one won't take as long.

Now try to start.

So if I pop the bowls then open the fuel valve will gas fill the bowls? That’s why I asked a question on how does the fuel pump enter into the equation. I know the planes gravity fed but it does have a fuel pump. :fainting-1344:

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2 minutes ago, Anticept said:

It will start without the fuel pump.

As procharger was pointing out, checking to see if it's firing is a good idea too. However, use a timing light to do it.

Will it fly if the fuel pump takes a dump?

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I strap plugs to cyl head with cable tie tight to ground trust me had

lots of experience. Timing light will work but I want to see a nice strong

blue spark. I've seen plugs fire but not strong enough or hot enough

to start engine. Just saying

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On 3/4/2018 at 5:52 PM, Buckaroo said:

So if I pop the bowls then open the fuel valve will gas fill the bowls? That’s why I asked a question on how does the fuel pump enter into the equation. I know the planes gravity fed but it does have a fuel pump. :fainting-1344:

Busy day for me, missed that.

The fuel pump has valves that don't completely close. There's always a little bit of bypass. Yes, you will see fuel dribble.

If it leaks, yes it will leak onto the exhaust, if you have the new pump. It's supposed to have a drain line run away from the exhaust.

I retract my statement about leaking onto the exhaust... it's not the fuel pump I am thinking of, it's the carb trays.

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If the fuel pump leaks it does not leak on a hot exhaust. The exhaust is off to the side. If it leaks it is on the air intake plenum for the older AC pumps and the new Corona pump has a drain tube. This new pump can have a drip or two occasionally. 

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The more I learn about the Rotax set up the more impressed in the simplicity of the design. No carb heat, fail safe fuel pump, gravity fed fueling, basically two separate motors in one, etc. 

I still am somewhat confused about the ignition system. Is it redundant as well?

 

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I retract my statement about leaking onto the exhaust... it's not the fuel pump I am thinking of, it's the carb trays.

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No problem these discussions are very cool and productive! Thanks for the support! :)

This forum keeps me going!

 

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So this morning I go out to the hanger armed with knowledge from this great forum on how to handle the no start problem. The only thing I added was a can of quick start spray to shoot in the air instake. Before my buddy shoots the spray I try a cold start and it immediately fires up. 

The no start day I had it on the Tanis and didn’t choke it. Then as I wrote it wouldn’t start in any condition. 

Could I of flooded it? At the time I thought that and tried a full power no choke start to no avail. She ran today like a rapped ape! 

 

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It's possible.

On the carb engines: if you crank with wide open throttle and no choke, it will purge the cylinders, but be warned: IT WILL FIRE RIGHT UP ON A HOT START LIKE THIS. First hand experience. Be ready to take that throttle right to 0 if the engine rotation starts to take off on you. Crank it a few seconds with WOT, then try starting with choke again.

Half choke is a thing as well! Sometimes half choke start is better!

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25 minutes ago, Anticept said:

It's possible.

On the carb engines: if you crank with wide open throttle and no choke, it will purge the cylinders, but be warned: IT WILL FIRE RIGHT UP ON A HOT START LIKE THIS. First hand experience. Be ready to take that throttle right to 0 if the engine rotation starts to take off on you. Crank it a few seconds with WOT, then try starting with choke again.

Half choke is a thing as well! Sometimes half choke start is better!

Thanks great tip! I’m thinking of abandoning the Tanis heat up and just pre warming up to temps in the 50’s with my big diesel jet heater :clap-3332:and using the choke like this morning. 

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I think there's a sweet spot for choke settings that is unique for every Rotax.  My sweet spot, on cold start, is a 3/4 choke with about 1/8" crack of the throttle.  I left my hair dryer plugged in the other day on a very cold day and got busy getting ready to fly and I forgot about it.  The engine was pretty much warmed up when I went to start with 3/4 choke.  Nope, no start.  I shut off the choke and it started.  I think each owner probably needs to find the correct choke setting for good starts.  The choke is pretty sensitive and I think it is easy to over choke (over enrichen) when starting.

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Has anyone had an occasion of a severally flooded engine? Mine was just dead no start the other day no matter what combination I tried. Then this morning semi cold she started full choke in one rotation of the prop. 

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Buckaroo

Do this a few times and do not deviate from it and let us know. 

All first starts should be full choke and crack the throttle 3/8"provided that your idle rpm is not over 1900 rpm after it is warm. Hold the key until it starts. Don't turn lose just because you think it might start.  The starter will automatically disengage at around 850 rpm. After it is at running temps then no choke just crack the throttle. None of my clients have issues.

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