On 5/25/2023 2:58 PM, Charlie England ceengland7@gmail.com wrote:

On 5/25/2023 8:13 AM, Finn Lassen finn.lassen@verizon.net wrote:

For those of you who use the AR2592 spark plug in the Renesis, do you use the 0.6mm gap the plug comes with? I bought 8 of them some years ago.

I've been using the stock plugs (RE7A and RE9B) for maybe 100 hours by now. Experienced a brief 200 RPM drop on last takeoff. Wondering if it's time to change plugs. Or re-gap the stock plugs to what?

What can I learn by looking at plugs?

Best way to clean them?

Finn

Since no one else is jumping in...

I don't remember ever swapping plugs in either of the RX7s I used to own, but based on general info for IC engines, the general appearance of the 1st and 3rd look to me like they're running way too hot.  Here's one site about 'reading' plugs:
https://www.lazerhelmets.com/lean-spark-plug-chart/

At $5-$6 each, it's hard for me to justify cleaning/gapping an old worn plug, especially if it looks pretty rough.

Charlie

Not sure I'm seeing the same thing as you in that chart. Actual plugs are darker than in the picture.

1st and 3rd are the leading plugs. Wonder if the small hole for the trailing plugs causes them to have less crud.

Also that crud makes me wonder if I should mix less oil. Still using about 1oz/gal. I think that Tracy mentioned using less for the Renesis. But then he's using a 50/50 mixture of MMO and 2 stroke oil.

I was going to replace them with the AR2592 but then got thinking about correct gapping.

Finn