I was breaking in my new DA-100 on test stand yesterday and run pretty good for 2 hours. Today I tried to run it another two hours on test stand, it start easily and run about 20 min then quit, I tried to re-start it but can't, flip it and it run about 7 or 8 sec. then stop, it can't run continuouly, I checked fuel line, there is no leakage, check spark of plug, it fire, I just can't find any error but it can't run, do know why, I am using 92 fuel with 1:32 and let engine running at 2000 rpm for breaking in. any thought about this problem, appreciate your help.

My guess is you fried it. I would never, never, never break in a gasser on a test stand especially for 2 hours.
Just my opinion.

There is really no need to break in a 100cc gas engine on a test stand. They break in just fine in the air with a lot more air cooling the engine. This may be more for future reference though, sorry to say but yours may be damaged. Send it to DA.

I agree with everything said in the other replies. However, before you send it back to DA, I'd remove the carburator and disassemble it and thourghly clean it. It's ppossible there could some residue in it from the machining process that is causing a restriction somewhere.

If it runs for 7 seconds and quits, it's likely a fuel delivery problem. Remove the carburetor and check for dirt blocking the screen under the cover. While it's not a good idea to run these engines on a test stand for a long time, I doubt you fried the motor letting it idle at 2000 rpm.

Also check your ignition battery for low voltage under a load.

I would check two things.
First, remove the cover plate (non-diaphram side) and see if you have crude on the screen. Blow it off with Carb Cleaner.
Second, make sure your ignition battery is charged and you have no loose connections.

If it still doesn't run, then send it back.
I think you already know not to run it on a stand.

Thank all for your reply, just check my battery, it is low voltage[>:]
Hope i didn't destroy my engine, will try it tommorow and post result.

Hi Gary, How you coming on the Sukhoi? You're the only one that assumed the obvious, "BATTERY VOLTAGE."

Nope Bob.
I won the quick diagnostic award.....check the time stamp on the message.....

Oh... I really hate to hear about people running these engines on a "test stand"... just put them in the plane and fly 'em there is really no benefit whatsoever of running them on the ground.

Besides... who wants to listen to a chainsaw drone for hours and hours....
DP

I stand corrected, I didn't read the edited portion of your message. Sorry..........you win the $64000.00

If that motor got fried running at 2000 rpm for 2 hours I would never buy a DA.

I agree with the fly to break in, but talk about making someone feel a little worried[&:]

Also check with the 3W engine manual, they say its not a harmful practice for there motors but recommend in the air as the best way to go.

Here is what 3W manual say

We strongly suggest to use following method:

Mount the engine onto a test stand with cylinder(s) being in free air to make sure that the air can flow propely over the cylinder(s). This is extremely important for good cooling.
As per our instructions use mineral based 2-stroke oil, mixture ratio 1:30
Start the engine, set RPM to 2000 - 2500 and let the engine run for 10 to 20 hrs.
We suggest not to use mufflers due to the rich mixture.
When breaking in period has been finished, follow our installation tips to mount the engine onto the motor-mount.
Use fully synthetic oil mixture 1:50
enjoy the power of your engine from the first flight on

Is there any difference between DA and 3W? I confuse

Just put it in a plane and fly it. How hard is that?

Don't follow the 3W instructions to break in a DA engine.

My engine did the same thing on my airplane. Flew fine through a gallon. Then it would crank and runn for a few seconds. I changed all of the lines and nothing fixed it. I finally let it run for a few second enough times that it fired and has run fine for the past 2 gallons. You may have a different problem since breking engines in on a test stand does cause more heat buildup. But if you have an hour or so, keep cranking it. If it does run, then good. If not, then you needed to send it back to DA anyway.

I was only using that as an example, you can't fry a motor doing this if the needles are set well, and there is good air flow. DA may not recommended it, and for there own reasons, the safest way to break in a motor is in the air.

However if done right I don't think it will even harm a DA, and will give it a chance to break in. When its winter out, like we get in some places, its nice to get a jump start for the following season, tune up that motor, run it in some. But for 10-20 hours and no mufflers, good grief, I pitty your neighbours.

My 3W manual for my new 80i says to:

"start the break in process of the engine on a test stand for approximately one hour. This time should be used to get familiar with the engine. Do not run the engine at full throttle for more than ten seconds during this test stand break in. The reason for this is that you are not getting the normal cooling effect that you would if the engine was in the model flying.

Another method that can be used for break in would be to set the engine between 2000-2500 rpm and let it run for 4 hours. After that the engine would basically be broken in."


Well I ran it for 1 hour just to see what kind of RPMs I would get, tuned it up well, and I will leave it at that. Now I know what props will work

I doubt you did any harm what so ever, clean the carb as described above, charge the battery and put it in a plane and fly it. If the jugs turn a real pinkish color that means to much heat on a DA engine.

Hi, Guys after changing new battery and run DA-100 again, all problem gone, set needle, very smooth transition, turn NX 26x10 low 1500, high 6300 (still at rich side),fortunately I didn't fry my engine, I broke in all my gaser on test stand before, no matter what brand, DA,3W, ZDZ, MVVS, and did have any problem at all. But I will take your advice, just put new engine on plane and go fly in future.

Thank again for input.

I just picked up a BME 100 that should be here by Wednesday.
I wantr to get it together and go to the Toys for Tots Fly-In at the Dixie Aeromasters field on December 10th.

We shall see how it goes!

Look forward to seeing you Geist.
Wayne.