All Day Dan

My Feedback: (5)

I have a perfectly running Brison 3.2 that has been changed to electronic advance using a CH module. The timing has been set to 28BTC in accordance with Milton’s video. A Smart-Fly kill switch is between the ignition switch and the module. On occasion the engine kicks back on start up and backfires and then won’t start at all. I have changed spark plugs and ignition modules to no avail. I have rechecked the timing more than once. It usually happens after about 6 eight minute flights and the engine has cooled off. The ignition battery has plenty of capacity and always measured strong under load. A starter will get it going. This has been happening to two of the same engine, ignition combinations. The next thing I am going to try is to bypass the kill switch and/or change the sensor. Any other ideas? Are these symptoms typical of a timing problem?Dan.

av8tor1977

My Feedback: (6)

Ch Ignitions made a lot of ignitions that were not automatic advance. In later years, they sold what they called a "Synchro Spark" that was a module that plugged in between the sensor and the ignition box, and provided automatic advance. Then they made ignitions with the "Synchro Spark" automatic advance built right into the ignition box. There are a lot of the older systems out there that did not have automatic advance. Look carefully on your ignition box, and see if it says "Synchro Spark'. If not, it does not have automatic spark advance, and is running on whatever you set the timing at, all the time. This could cause a kick back problem, especially on a larger engine and/or if the engine gets slightly flooded on a start.

Depending on your setup, a good backfire or kickback can make the timing slip too.

AV8TOR

CK1

My Feedback: (60)

Sometimes their will only be an S or SS and not the entire "Syncro spark " scribbed into the case near the date . Brisons will also bite if they are too lean on the low needle and have the throttle open too far , or flooded (odd right!!!)
If you verify that you do have a synchro ignition I would recheck the fixed timing again and be sure you are setting with a counter clockwise rotation of the crankshaft. If all else fails to resolve the issue replace the p/u sensor I have had them cause your concern but it is rare . Usually the sensors just completely fail. The usual cause is an open high tension lead by the spark plug cap being off the plug while operating the ignition.
Keep us posted

All Day Dan

My Feedback: (5)

Thanks guys. I got the module from Adrian when I switched over to electronic advance. It's the right one. I ordered some five cell 2100 mah NiNH ignition packs from NOBS Batteries. My four cell packs were two years old. The problem showed up after the first hour of flying with 1400mah Nicads. They should have had enough capacity and always cycled well. The slight drop in voltage could have caused the problem. Maybe the new packs will do the trick. Dan.

jerdavis

My Feedback: (3)

I've had similar issues that have turned out to be:1) Overheating the carb, resulting in vapor lock.

2) Oil fouled spark plug due to running the engine prolonged at too low power. i.e. A long gliding approach to landing at idle power.

3) A just plain fouled/bad spark plug.


Jerry

CK1

My Feedback: (60)

Dan if it turns out to not be a battery issue ,either discharged or bad. Try opening the low needle about 2 blade widths of a screw driver. Brisons can be a little touchy on a hot or warm restart if they are a little lean on the low needle.

All Day Dan

My Feedback: (5)

Another thank you. The fresh sets of battery packs are on the way thanks to Steve at NOBS. I always get great service from him. I got the same symptoms with a new spark plug. That's a good point about the low speed needle. I was kind of lean and it was around 90 degrees. The engine was also warm. Dan.

All Day Dan

My Feedback: (5)

I had one of the engines out this week and got ten good starts. The five cell battery pack from NOBS was installed. I richened the low speed needle valve a bit, put the prop at the 3 o’clock position and used some mighty flipping. The chicken stick I use was slipping off the prop at the 2 0’clock position. It all worked out. I’ll have a second engine out this coming week. Dan.

All Day Dan

My Feedback: (5)

The starting problems with my three active Brison 3.2s have been solved. It turns out that I had the low speed needle valve much too lean. I was able turn it out 1/16 of a turn or more and the engines started up as expected. The idle was not effected. This is surprising because the engines always idled well. I am now putting much more force into my propping. I was getting pretty casual with it as time went on. I tried a heavy reinforced leather glove but quickly abandoned it for the chicken stick after the first whack. I’ll let the stick suffer. I can not say for sure if changing the four cell battery pack to a five cell was beneficial. The old packs were over two years old and had lost about 20% of their capacity so new packs were necessary anyway. Thanks for the inputs. They were very helpful. Dan.

CK1

My Feedback: (60)

Dan , its good to hear that you got things worked out.
Happy flying