If you have removed the resistors in the spark plug caps or bought new ones without resistors, you will need to change the plugs you are using to a model with a resistor inside the spark plug itself. We have found the NGK DR8ES-L plugs to work well:
They’re inexpensive and readily available online – you can find them on eBay inexpensively
. The product page is here. We didn’t have much luck sourcing them from the local chains like Supercheap Auto or Repco.
Some quick specs:
- 12mm thread, 1.25mm thread pitch
- 17.5mm hex (11/16″)
- 19mm (3/4″) reach
- 0.7mm (0.028″) gap
- Heat range 8.5
- Nickel electrode, 2.5mm
You can buy them from Amazon: