MTD Genuine Parts 759-3336 PK2 Replacement Spark Plugs (RC12YC) – Copper Core, 14mm x 1.25mm, 2 Pack – Compatible with Riding Mowers

I’ve been having issues with my mower ever since I got it. I have been cleaning the carb every year and one year even paid almost $100 for Lowes to “repair it under warranty” (what a scam!). This year nothing seemed to do the trick until I saw in the manual that spark plugs can be part of the problem. I don’t have a gap tool and manually adjusting the carbs by eye made the situation worse (wouldn’t even start with starter fluid). So I tried buying new plugs figuring they would come from the manufacturer properly adjusted. Unfortunately the two plugs arrived with wildly different gap sizes and probably nowhere near spec. I decided to install the one closest to the original and it immediately fixed my problem. Side by side comparison shows how soiled the original was.