yet another "rough running" thread

Hi All

Make sure when you thread on your ends that you use a dielectric grease on the wire end.  The reason you have the issue in the first place was most likely the buildup of corrosion on the connection from moisture wicking into the wire ends.  Rotax use the good stuff, copper stranded wire, but between the threaded prong and the wire you can get corrosion after time.  After you nip off the end put a dab of the grease on the tip and the side of the wire where it will go together.  Your problems will then be a lot less next time.

Cheers

Along with the corrosion protection and better contact I believe The grease will also help the threaded prong screw into the wire easier and have less damage as the threaded prong is screwed into the copper wire. It's a small help, but I think it does lube the process some.

Very true, and thank you both for noting.  Yes, my original lovely detailed reply also noted a "booger" of dielectric grease at each end :-)

GAAAAAH! OK, lesson learned: DO NOT draft posts in the web interface, lest ye lose it all AGAIN *sigh*

So, once more, the short form. Taught a great -- and smooth -- lesson today, but back at the hangar for more inspection we find roughness anew. Starting over ...

We now know:

- choke test was unsurprising
- stator & modules are good, as verified by swapping red wires and MOLEX plugs
- all new spark plugs
- ignition wires all freshly trimmed and re-booted
- boots all attach cleanly to, stand straight on, and need a good tug to pull from the plugs
- boot-wire-coil resistance (in kOhms, mind you, not Ohms; thanks Kevin Stewart) is
  A - 1/2T = 15.75-15.78
  A - 3/4B = 15.69-15.72
  B - 1/2B = 15.82-15.82
  B - 3/4T = 15.76-25.77
as I struggle to hold probes in place across the engine
- carb venturi slides are smooth and, more importantly, similar as far as my big monkey fingers can tell
- running without the air filters changes nothing and the carbs are standing straight & happy
- no intake leaks, as verified by starter fluid along the carb boots and intake manifolds

Once again we're at a loss. The only thing we can think to do is swap the boots on the wires, but that seems a desperation move.

Time for a shower and a sleep now to let the subconscious chew on this, but we still look forward to more suggestions :-)

D & L

Long shot:  A brand new spark plug has been known to be a dud. Re install the old ones and see if the engine still runs rough.