Ignition problem

[Wheels]

My 80HP 912 Rotax had a mag check failure at run up.
First mag drop was almost nill, second mag was an erratic and rough running engine. Classic symptom of a module failure. I pulled the 4pin connectors and swapped them, no change. I pulled the ignition leads from the panel and swapped them and was able to swap the failure from mag 2 to mag 1. So I thought I had isolated the problem to the ignition wire from the panel/mag switch.
Figured this was the problem so I ran a new wire and bullet connector from the connection, test was negative. Did the same for the other bullet connector and still having the same issue. I did a continuity test on the switches and both checked out. could the switch be bad anyway? I'm now lost. Ideas?

[Av8r3400]

. I don't have good news for you. This is nearly the exact problem I was having.

Through process of elimination I was able to localize the issue to one ignition box. Replacing that one box with another from a good running plane did NOT fix the issue. I wound up replacing both boxes (with the new style and cheaper 6x6 pin) to get the problem fixed.

The full story:
http://www.teamkitfox.com/Forums/showthread.php?t=7119

[Wheels]

What did the new modules cost you. I am thinking of just parting out the engine and installing the brand new one I have one on stand by. I was going to change out in september anyway and I don't think this engine has any real value on the market
unless it is proven sound. I have had two electrical problems in a month and both related to its age. the wires just look old. So instead of spending time and money on the older motor, I can put in the new one and call it good and go fly. the parts alone on the old one should be worth most of the install costs. I really don't know what this thing is worth but nobody seems interested in it for the money I was asking. oops.
on the other hand, I need to fix the problem just to satisfy myself that I didn't waste 6 thousand plus dollars in training costs for all the schools I have attended since becoming a Rotax owner. I've kept it running for 5 years but most of the help came from this forum and rotaxowner.com. Honestly, all the experts live a few keystrokes away.

[jmodguy]

Been doing a little research on your issue and I found someone with an issue similar to yours. Their approach was to start the engine on 1 module only. L then right. If it starts on one and not the other then it becomes clear where the faulty module is.
As we discussed the other day, I really do not like bullet or other "rolled" contacts in such an extreme environment (engine compartment). That includes Molex and DB type conectors!

[Wheels]

I'll do that start trick in a few minutes. The new engine install will include moving the modules to the cockpit side of the firewall. I think slyfox did that and I saw it on another plane down in Corning California. In the meantime, I do want to fix this. Even if the engine goes for sale as a bush boat engine, it needs to work reliably for what it is.

[Av8r3400]

That engine will easily sell sans ignition. I'd buy it if you were closer. My module replacement project cost me in the neighborhood of $1500 with the conversion parts to the new style modules and plugs.

IMO, I would not put them through the firewall to inside the cabin. These modules and connectors are designed to be in the engine compartment environment. Adding a few inches to the wires to put them on the solid side of the engine mount is one thing, but inside the cabin is not needed.

[jtpitkin06]

Rotax ( and Lycoming 233) mount their modules on the top of the engine. The modules get plenty of cooling when the engine is running. The problem occurs when the engine is shut down. The residual heat in the motor rises up to the modules and cooks them. We had three failures going to OSH in 2014. Lycoming replaced a failed unit with a factory new one. It ran fine and the shut it down for 30 minutes. That's all it took to cook the brand new one. Lycoming now says to put the module on the fire wall. After the relocation we did not have any failures for the rest of the trip. My recommendation is to do the same with the Rotax. Get the modules off the engine and put them on the firewall.

John P

[Dusty]

I extended my wiring and now have my modules in the cabin.
I believe heat is a killer of these units 80c?,I use an undercowl temperature gauge,30c cowl temp in flight, but 60c after a cool down and shutoff.
This is with a round cowl and our cooler environment.
A smooth cowl and hot environment may be pushing the temps to the limit.
I suspect the ignition mounted to the engine is more for practicality as a complete power unit than a serviceability issue.
Our local rotax guru is working on a replacement for the Ducati trouble/ expense boxes using two aftermarket motorcycle fully programable units to replace each unit(more redundancy)
When we can offer this conversion as a tested plug and play option I will make them available.
Be patient as things happen slowly in this part of the world!

[jmodguy]

I think JT and Dusty are right. Heat (and cold) soak will kill electronics... I have seen it in environmental testing.

[jiott]

Since it seems to be the hot soak after engine shutoff that is the main temp problem (for both ignition modules and vapor lock), I have wondered if it would be worthwhile mounting a small fan (something like the heater fan units) down near the cowl air outlet on the bottom. Then when you switch off the engine, you could switch on the fan to pull outside air thru the engine compartment for a cool-down period. You could even get fancy and make it automatic for a certain time period. Many cars do this with their electric radiator fans-you hear them running after the engine is off, probably for the same reasons.