ForeverHero

My Feedback: (1)

Greetings,

I have a DA-50 mounted in a BMW Yak that I purchased from a fellow pilot at my field. So far I have 8 flights on it but the previous owner flew it for several months before upgrading to 100cc planes. My question concerns starting the plane for the first time of the day. When I first flew the plane it would take 5-6 flips, with choke on, before it 'popped' and then I would shut off the choke and flip the prop once again and it would start right up. Recently, during the unusually hot weather here, it wouldn't start at all; kind of acted like it was flooded. So, I would let it sit for 15-20 minutes and then try cranking it over again with both the choke on and off but nothing happens. Each time I have had to use a high-torque starter to get it to finally turn over. Once it did this, it ran fine the rest of the day; it just seems to act like this on the first start of the day.
Is there anything that I should look at or adjust to correct this problem? Please let me know.

Thanks,

Mark

3d-aholic

My Feedback: (7)

Once you start using a starter, you probably will have to use one forever...thats been my experience with ALL motors. Maybe its superstition but I've only seen others confirm it.

bubbagates

My Feedback: (32)

Sounds like you may be a bit lean on the low needle. Other things to check is the pump diaphragm getting weak, dirty fine mesh screen in the carb, air leak and on the far fetched but possible side, is the choke closing all the way and has the throttle plate come loose...

I've started engines by hand that others swear need a starter. ZDZ comes first to my mind. I ran into this this past weekend on a ZDZ Super 80. Showed the owner the 5-5-1 rule and the engine responded just like it should. Magneto driven engines need to have the prop in the correct spot, Zenoah comes to mid as well. Using starters does work and I'll never say not to do it but if you run a very expensive tru-turn or CF or even fiberglass spinner I would think you would not want to run a starter on them.

GuyIncognito

What is the 5-5-1 rule ? New to gassers and very interested.

bubbagates

My Feedback: (32)

Basically it's for ZDZ engines and goes like this.

Ignition off, full throttle, closed choke...flip it five times
Ignition off, full throttle, open choke...flip it five times
Ignition on, close throttle to idle, open choke...flip it once and it's running....sometimes twice if you slip off the prop

All flips must be good ones, if you slip off the prop, do not count that flip....works every times unless there is a carb or ignition problem

pe reivers

That rule very much is like what zenoah wants.
I observed with a twin engined scale craft:
4 flips with choke on till first fire
8 flips with choke off till running
all this time and again, and very consistent over both engines.
This was the procedure the guy used. Mine is slightly different, but almost the same, and I use less flips. But then, I do not run zenoah's. Every engine has it's own procedure that works best.
The rear rotary ZDZ may be a bit different though. Not from experience, but from a technical vieuw, the procedure might differ a bit due to the added rotary drum, though I doubt it would meen a much different flip count.
Most of the time it is too lean idle settings and too little oil that cause hard starting, and the need for an electric starter.

raven7usa

My Feedback: (7)

While we're discussing the DA 50, Those of you that use a servo for the choke, do you remove the detent on the choke shaft?

bubbagates

My Feedback: (32)

Nope....

littlecrankshaf

My Feedback: (58)

Mark,

A couple of things to consider. First, DAs need to be "hand propped" more briskly than some other engines or electronic ignitions that use Hall Effect switches.

Secondly, it is possible that the reed valves are not closing as well as they once were causing fuel draw to be reduced. My DA 50 exhibited some of the same symptoms but after modifying my starting procedures I am satisfied now. One the first start of the day; insure the choke is fully closed and flip the prop aggressively until it pops(may take many more flips if you drain the fuel after each flying session) or runs for a bit. Open choke and flip until it starts. If it then dies, close choke and start over. Good luck.

Rush7

My Feedback: (74)

One other thing that I found to be effective with my DA this weekend was that I was having a problem getting it to start and it was quiting just about every time I would taxi in on low idle from a flight.
Cure was I changed the spark plug. Take the pulg out and if it is covered pretty good with carbon change it out and you will see an instant improvement in starting and engine performance.
One other thing is that my DA likes to be primed before I start for the first time evey day.
Steps:
1: Ignition off wide open throttle flip prop 4 to 5 times and its like you can hear it draw fuel
2: Ignition on high idle on choke on flip prop until she pops
3: turn choke off usually 5 flips and she is running on high idle

Also with the very hot weather that we had her it seemed that the motor liked to be riched up just a bit on the low end. Found this when testing the transition and my motor stumbled.

I use this procedure once motor is running and warmed up. Clear it out. Return to idle let motor idle low idle for 30 seconds. Transition briskly to full throttle and if motor stumbles it is to lean. If it bogs it is to rich. (All on the low end).
Set the high end needle by a tach and by making tempeture readings after flying.
Sounds a little crude but it has seemed to work out for me.

pe reivers

Ditto this, except for the temperature measurement AFTER flying. Measurement should be done during flight usin a peak sample/hold device like the Venom temperature gauge. In the landing approack the engine has been idle too long to get any valuable reading.