Rotax Hard Starting. NGK resistor plug caps are used on many Rotax engines. Model LB05EZ is sold as a 5k ohm ( = 5000 ohms) spark plug resistor cap. Older plug caps may go high resistance or open circuit. This makes for hard starting, and may overstress the ignition coil etc. A cheap meter with a resistance range can test these caps. A first easy check is the resistance path between the two plug cap clips at either end of an ignition coil. The resistances are additive: two plug caps at 5000 + 5000 ohms plus the coil resistance which is typically 7000 or 8000 ohms - total: 18000 ohms (18 k okm). Faulty values on hand are 40+ megohms (40000000 ohms) and too high to read. To check the resistor cap on its own, unscrew the cap from the ignition cable. There is a 'wood' screw to capture the wire on the cap. Resistor plugs are often used with these caps. NGK BR8ES is a 5000 ohm (5k ohm) spark plug often recommended for these engines. These can be checked between tip and central electrode. No failures have been noted.