Robin 350 cc engine weak spark problem

[Donald Widing]

New to site: Have 350 cc Robin, orange spark from coil. Both plugs receiving steady spark through plugs, but orange, not blue. Planning to replace coil but not sure if the ignitor is contributing to this problem. Believe Pulsar is good since both plugs receiving consistent spark. Cleaned all engine ground and other connections. Also, please advise location of ignitor (behind fan cover?) Also, recent carb replacement and compression is 155 both cylinders. Valves adjusted .004 which I do annually. Thanks

[golfcartg]

Welcome to the site! There's a thread here that thoroughly covers a wide range of common issues with this engine including some potential causes you may not have considered yet. Running through it should give you a clearer idea of what might be contributing to that orange spark and whether replacing the coil is the best move. And if anything isn’t quite clear feel free to reach out with specific questions!

[Michael Eddie]

New to site: Have 350 cc Robin, orange spark from coil. Both plugs receiving steady spark through plugs, but orange, not blue. Planning to replace coil but not sure if the ignitor is contributing to this problem. Believe Pulsar is good since both plugs receiving consistent spark. Cleaned all engine ground and other connections. Also, please advise location of ignitor (behind fan cover?) Also, recent carb replacement and compression is 155 both cylinders. Valves adjusted .004 which I do annually. Thanks

The Robin EH35C ignitor location is buried on the drivers side of the solenoid bracket. Before you commit to replacing the coil, grab your wife’s hairdryer or a heat gun (on low). Warm up the coil to see if heat has any effect on the spark color. Coils sometimes have internal micro fractures that show up more when they’re cold or hot. If the spark changes color or strength, you’ve confirmed the coil is on its way out without buying anything new yet.

If not, bend a piece of metal coat hanger or some heavy duty fence wire into a U shape. Connect it between each plug wire boot and the installed spark plug itself one at a time leaving about a quarter inch gap. If you're working in a shop, dim the lights, crank the engine and watch the spark. If it arcs across the gap with good strength, the coil might not be as bad as you think.