engine runs rough

[Slyfox]

tell me more about this. willing to spend whatever to fix this. about a year ago I changed one module to a newer soft start with extra wiring for the soft start. the other one only has a cold start up problem that works itself out after I start the engine, generally will start working when the rpm's are over 2000. I left it alone with 1000 a pop. I've run on one mag while flying and no change going between the two. But a programable module does sound interesting. give me the web site or something for this. thanks

[AvDES LLC]

If you’d like, I have one of my old cdi boxes that I can send your way for you to swap out with your others to see if the problem goes away. That way we can narrow it down to the ignition before you go spending a ton of money. It will be the one that doesn’t have the broken internal wire - promise! Haha. If that solves the problem and you want to go the programmable cdi box, we (AvDES) sell them along with a mounting kit to bring them into the cab. That said, I’m not a paying sponsor on the site (yet), so I cannot openly discuss the kit in the forums. Touch base with me in pm and I’ll shoot you my phone number if you’d like to discuss your problems more.

[Slyfox]

right now my plan is to rip the coil-module assy out and check all wiring and do a test on each coil with heat. if that passes than yes I'll consider it. thanks

might be a few days, been working hard and I'm going fishing this weekend. lol

[AvDES LLC]

right now my plan is to rip the coil-module assy out and check all wiring and do a test on each coil with heat. if that passes than yes I'll consider it. thanks

might be a few days, been working hard and I'm going fishing this weekend. lol

sounds good! And lucky man! I’ve been trying to escape to a fishing hole for months now. Good luck!

[Slyfox]

a little update on this. I cleaned the plugs, they were quit black. started it up, and it ran very good on the right mag. left mag, ran like it was not on all 4. problem is in the ignition. I had my spare cdi and installed it on the left side. switch that is. not sure at this time which coils that one runs. will find out though. I have the rotax heavy duty manual so I have the wiring diagram for this. I replaced that cdi about a year ago with a soft start. the original cdi quit working when cold. installed that cdi and ran the same, so it is working. I am starting to think coil at this point. I need more time to dig in and find the problem. let you know.

[AvDES LLC]

Good to hear the troubleshooting is going well. If it ends up being a coil I HIGHLY recommend reaching out to Hal. He has a stash of them and will save you big bucks.

[Slyfox]

like I said I need to find out which side I'm working on, a or b. I know which side is which on the diagram not on my plane yet. going to rip the system off the motor mount and dig in maybe tonight. I was way excited that it turned from an intermittent problem to a hard problem. I'm sure I'll find it.

[Slyfox]

well it tested positive for a bad coil. I ordered one and I hope this is the end to this saga.

[sturdee]

Check your connections too each plug cap! Found one that was not into the centre wire and caused a right huntdown, symptoms as you had

[Slyfox]

update:
I replaced the spark plug in no. 1 top. I now have a running engine. I cleaned the plugs as they were black from ground runs. starts nice and flew for an hour in the pattern. I have a slight vibration from 3400rpm on down, idles just fine. Not sure if this is normal or not, the cowl will vibrate at the front section when it does it. plenty of power. I've done everything you can think of on this thing. the idle circuit set screw was set a 1/2 turn out and I increased it to 1 after landing. I didn't want to pull the choke for that has fouled the plugs in the past, but if I need to I will the next time I fly. there was no fall out of cylinders on climb out at all, just running with a little vibration under 3400rpm. what to do, not sure. on a mag check at 4000rpm on the ground, both are equal. with a drop of about 150 or less.