GUys,
When I first ran my DA50, it would idle forever, and I mean forever. However, I was slightly fouling plugs, so I slightly leaned out the low end, and this also got rid of all the burbling. THe engine runs great now, and the only problem is that its idling is funny.
If left on idle, it will SLOWLY, over a period of a couple minutes, begin to get lower and lower and lower, until finally, it will die.
After a couple minutes of idling, if I give it just 1 click of up throttle, it will also start to die. However, if it is left idling for a couple minutes, and I then kick it up to 1/4 or 1/2 throttle, it is fine.
THis seems to me that it is slowly loading up. What would you guys say?
Also, it appears that every time I go to the field, I have to take the plug out, and clean a little piece of carbon buildup from the plug. After I do that, it cranks right up. Is this just because I am running Lawnboy Ashless on break-in? I also thought this may be because the engine is stored inverted, and everything runs down to the plug and just sits there until I fly again.
Could someone please tell me if I am correct in these assumptions?

The only thing you changed was leaning the low end mixture. Then it started to idle funny. Hmmmm.



I don't know......maybe the the low end is too lean...

Diablo,
I had to lean the low needle because of a good bit of burbling, and also (mainly) the engine wanted to flood while attempting to crank. Maybe I shouldn't have done this, but it seemed like it was really flooding and I figured the low end was too rich?
It really sounds much better in the air after leaning the low end a little.

This is one of those things that can onle be answred by listening to the engine. If you don't know, get somebody that has messed with these gas engines to help you. You do not want to run it lean...especially during break-in. I could take a guess myself, but without listening to it that all it would be...a guess. Best thing to do is to get some help from somebody who can tell by listening. That is a good engine, and the reason I wrote this is to make sure nothing happens to it. I could tell what it's doing in 10 seconds, but I'd have to hear it, and see the way it was taking the throttle and what it sounded like at mid. It could be something as simple as you are idling it too low righ now. They will idle lower after the breakin process than they will when new and tight. Whatever you do end up doing though, make absolutly certain you don't run it too lean during the breakin. You wanna go easy on them when they're new, and they'll breakin and run like hell down the road! hehe

Paul:
Burbling at what throttle range?
Leaning the low needle leans the entire throttle range. If it started out too rich from 1/2 to full throttle, then leaning the low needle would fix the richness from 1/2 to full throttle, but would also make the mixture too lean from idle to 1/2 throttle. The high speed needle needed to be leaned (in this example) rather than the low speed needle.

I would return the low speed needle to its original setting and check acceleration from idle to about 1/2 throttle. Adjust the low needle for snappy acceleration.

Then set the high speed needle for max rpm with a tach at full throttle. Set the needle so it is as rich as possible and still at max revs with your particular prop. Test fly it.

This cannot possibly be a "DA" engine..................