On the oil pan.
I have a 2000, I'm sure they are the same..take the four bolts off the top cover (the one that says 2.4 or whatever) and carefully lift the piece out...there are plastic and rubber boots attaching the cover to the plugs.
You need a six extension and a spark plug socket with a rubber stop inside. The spark plugs are located on top of the engine. They are about 4 inchs inside the head. Using the extenion put the socket with the rubber piece inside which will grip the plugs when they are unscrewed allowing you to remove the plugs. When installing use the same socket but press the plugs inside the socket so they are being gripped which will you to slowing lower them inside the head with the extension and get them started. I suggest you start them by hand.
fixed it was spark plug wires.
maybe some water stuck in the cylinders
Check plugs and plug wires---worked for mine.
Johnson outboards, model RDS-24L, would be a 1962 year model, 40 hp. the boat motor is a 50 hp.
i think you disconnect one of the plug wires or you need to change one of them . It could be the oxygen sensor, valves, plug wires or a sticking fuel injector. You'll have to get a little more specific. If it ran well BEFORE changing the plugs and now it doesn't, perhaps 2 of the plug wires have been cross-connected.
24L/1500mL = 24/1.5 = 16 buckets.