Bill Vargas:

What is a twin spark filter?

Originally Posted by whaturi

As the subject says, the 3W 150 twin spark I am currently using (just back from Aircraft International for alum. carb block, carbon clean, and test run) runs on one for the first 5-15 seconds after starting.

It will do it cold or hot.

Is this normal?

What carbon did the clean? I would image the cylinders were removed by AI to clean the carbon?

I think they cleaned the ports?

I took the suspected cylinder off yesterday. Everything looked fine. Very little carbon and no broken ring.

Originally Posted by whaturi

Bill Vargas:

What is a twin spark filter?

Its a little electronic board that has clear heat shrink around it and splits the hub sensor signal for the 2 ignition boxes. From the Hub sensor it plugs into that. The 2 output leads plug into the ignition boxes.


Have you tried running a separate battery direct to each ignition box for trouble shooting? In other words,,, use only 1 battery hooked up to 1 ignition box at a time,,, are the results different or the same?



https://www.aircraftinternational.co...8/Default.aspx

Originally Posted by Bill Vargas

Its a little electronic board that has clear heat shrink around it and splits the hub sensor signal for the 2 ignition boxes. From the Hub sensor it plugs into that. The 2 output leads plug into the ignition boxes.



https://www.aircraftinternational.co...8/Default.aspx

I think that motor can run with one spark/cylinde no problem. So, try one electronic at the time with no interface, switch left/right spark cables, replace the electronic, do the same.
You will find out which part is falty.

I found out that, since you kinda have an older 3W engine there,,, you have one of 2 types of 3W ignition systems there. On the prop hub you have either 1 or 2 magnets. 1 magnet is the early style and a hub with 2 is the later. Also there's 2 leads coming from the Hub sensor and each wire plugs into the ignition box respectively,,, so no Twin Spark Filter. This leads me to believe one of 2 things/problems. 1, you have a bad sensor. 2, you have weak magnet(s) on the prop hub(cheapest fix of the 2). As for the sensor, not sure if 3W International has those anymore so best to call Gerhard for that.


btw, what's the serial number on that engine?

Serial number is 018505.

If I had to replace the magnet, how do I get the old one out? would I have to pull the hub?

In your first post you stated just back from AI which included a test run. Is it possible you trying to fix a non-existing problem? Most engines run a little rough until the temp comes up. I suspect both cylinders are four stroking until the temp comes up. I had a twin 40 cc with a dead cylinder and it was nearly impossible to start. I would verify both ignitions are working and enjoy the engine. I suspect that AI would have done so as part of the test run.

Originally Posted by whaturi

Serial number is 018505.

If I had to replace the magnet, how do I get the old one out? would I have to pull the hub?

No, the hub does not need to come off. Those little hub magnet(s) are brittle and with a small hammer and a small sharp punch you can tap on them and break them out.

Originally Posted by Tony Hallo

In your first post you stated just back from AI which included a test run. Is it possible you trying to fix a non-existing problem? Most engines run a little rough until the temp comes up. I suspect both cylinders are four stroking until the temp comes up. I had a twin 40 cc with a dead cylinder and it was nearly impossible to start. I would verify both ignitions are working and enjoy the engine. I suspect that AI would have done so as part of the test run.

I felt a big difference between the two cylinders after a short run started from cold. One I could hold my hand on, the other, it burned too much.

It is like a switch when it begins running correctly.

I could be wrong, and it could be "four stroking", I never had these issues before.

It seems to need some throttle transitions to "snap into" normal operation. Once I just took off without playing with the throttle on the ground to get it working right, and it simply stayed at half power for the whole (stressful) flight.

Have you called the G man ?

I just talked with him.

He thinks it is due to having just one 2600 mah battery running a twin ignition.

I will try adding another battery next time I fly.

Also, Bill Vargas informed me that the serial number indicates that my engine was made in 1985!!
Never would have bought it used if I knew that, but it seems to be in decent shape.

I can tell by the case design that engine is definitely not from the 1980's. At the absolute earliest the very tail end of the 90's and more likely 00-05.

You should swap both ignition leads and look at the power supply side before you go opening it up... if the battery is up to par, most likely 1 ignition has one side out and now the second ignition is starting to fail on the same side... so it runs rough then finally the electrons start to play nice and it cleans up. That is the whole problem with the twin spark concept, hey we have unreliable ignitions so let’s use two so it masks the problem. How often do people actually check to see both are actually working properly individually?