Office of Steam Forum for Model & Toy Steam Gas & Hot Air Engines

The Regular Stuff: Chat, Buy, Sell, Off Topic, etc. => General Discussion - Scale Model Gas Engines - Hit & Miss - Throttle Governed - Non-Compression – etc => Topic started by: Hassellbear on September 08, 2026, 10:57:28 am

Title: Re: Okmo Engine Spark Plug Connection
Post by: Raphael on September 09, 2026, 02:13:26 am

Hi Darryl,

I noticed the same thing on all my engines and simply trimmed a bit of the red insulation so the copper would fill the spark plug boot.

It’s not an issue as long as the spark is good.

Title: Okmo Engine Spark Plug Connection
Post by: Hassellbear on September 08, 2026, 10:57:28 am

While checking spark on my Z01, I noticed when the plug is fully inserted into the rubber boot there is a significant amount of space between the terminal end of the spark plug and the inner end of the boot. I noticed the same thing on my B01. There is enough space so that you can depress the end of the boot a good bit using your finger. My theory is the extra boot length doesn't always provide a good connection between the spark plug wire and the plug terminal. To remedy this I wound a coil using solid 20 gauge copper that fits over the plug terminal, slips into the plug boot, and presses firmly against the plug wire at the rear of the boot. After the mod, the spark was stronger and more consistent.

All the best,

Darryl