I obtained a used BME 100. It had a failed C&H ignition unit that I sent into C&H for repair.
The engine starts and runs quite well now but will produce a lot of RFI if I am not very careful to get a good fit on the spark plug leads to the spark plugs. Since I have to remove the plug leads to remove the cowl I am doing a lot of range checking with the engine running. With a PCM receiver this means a long walk every time the cowl is removed. I need the exercise but I am never sure the cap will remain in place throughout the flight.
When changing the spark plugs on my Ford I noticed they recommend putting a non conductive grease on the plugs when reinstalling them.
Anyone have a magic substance they put on a plug to help in this situation?

Not sure I understand..are you saying its hard to get the cap on properly and it interferes when its not on properly
the cap should take a good positive push to put on and then hold tight, if it doesnt..new cap

sorry if im misunderstanding

Yes I am saying the cap is hard to get on so that you are sure it makes good contact with the plug. There must be no gap in there or you will get RFI. The plug caps are new - I just got them back from C&H. The plugs are new.
Other people have used this type of cap for years. Its the same type of cap as used on most mag engines except the shield is supplied with a pigtail to ground the ignition. A magneto is already grounded.
I just wonder if someone has found some kind of substance that would help this from creating RFI. Maybe a conductive grease like is used on heat sinks would be better?

Vaseline maybe????

Not sure what spark plug cap you have, the rubber boot or the billett machined one???

Rubber boot

Conductive grease (heatsink stuff) BAD idea it will get hot and leak down the side of the plug......guess where the spark goes then?
If the metal clip is loose then give it a little squeez. But first take a spare plug and see if maybe the clip is squooze to tight to go all the way down.
I know you don't to hear this now, but this is why we always recomend the shielded caps, no they won't fit it the cowl and yes they are ugly but they stop the RFi problems.
As an aside there are lots of BME and Brison twins running the rubber cap with no problem.
Different problem possible, can you install an FM(PPM) rx and do a range check?? Engine off max range and engine running range. This might tell us something.

I know rubber caps have been used for years. I have used them before with no problems. In fact I have no problem now when I get the cap shoved down properly.
Its just that I have that 100 installed on a 20 lb airplane. There is a vibration mode somewhere above idle that shakes that airplane like a dog shaking water off his back. I am afraid it might shake one of those plug caps loose.
I think I am going to fabricate a bracket to hold them in place. Maybe a tie wrap to the hose clamp on the plug base.
I guess the conductive or non conductive grease is a bad idea.
I am not flying or doing any outdoor testing now. It was 102 today - too hot for me

Non conductive spark plug grease is OK. Go to NAPA and get some

tkg,
someone told me years ago to use the slightest amount of vaseline. Good/bad???? I have never ran into this problem, just need to prove or disprove an old wives tale that I heard

Not good. Better is the product that TKG described. I believe it's called silicone grease but I'm not positive.

Silicone Dielectric Grease, AKA spark plug boot grease, this is NOT the anti-seize that you put on the spark plug threads.

OK, I see a few things.
You have to make sure the boot is pushed down far enough that the metal clip goes around the top of the plug.
You also need to make sure that the clip is tight around the plug top.
If you are worried about the boot coming off, use a ty-wrap around the boot and plug to hold it better.
Strain relief the wire ground so it doesn't break during the engine's vibration.
If the BME vibrates too much, you may be running a rich low end. Lean the engine so it runs properly.
Last a boot grease can be used but it is not necessary. I would recommend getting the plug on the cap more than any lube.

OK lets talk about setting the low end needle. I was told to set it so that it would transition to high speed without quiting. Then set the high end needle for maximum RPM on high throttle. This usually results in quite a rich low end. On my G45 I have the low end needle out 2&1/4 turns. How do you set the needles? I admit I am no expert in this area. That BME sure can shake the airplane.
On the spark plug I think I will get the dielectric grease and use it in the boot. That will make it easier to get the boot on properly. Then I will ty wrap it down so that it can't come off.
Thanks for the tips everyone.

The carb on a G45 is the same as the G62, they must have gotten a good deal on HDA48D carbs...Kinda large for a 45...Try starting 2 turns open on both, set the high for max rpm first..