Performance upgrades on the Mercury 240efi?

[boyd petit]

We have a 2002 Seadoo Islandia with the Mercury 240efi which still runs good with the usual maintainance & I've read the other posts about changing plugs, the Head Temp. Sensor, etc. to maintain efficiency. Because I've added aftermarket products to improve performance on my trucks and cars, I was wondering if anyone has tweeked anything else like changing the spark plug wires to "hot" wires, or upgrading the plugs to a better brand, or increasing air flow to the intake?
Thanking you in advance for your response...

 

[Dr Honda]

Wires and plugs won't do much for you. Unlike a car engine... a 2-stroke normally is already running solid core wires... and the only good 2-stroke plug is made by NGK. Also... the "high-end" plugs (Iridium, Platinum, etc) just foul out because the electrodes are small.

There are other, mechanical things you can do, like change the port timing, or deck the heads about 0.010"... but when you start making those kinds of changes... you need to change the pitch in the impeller to take advantage of the new power. Also, you start to loose reliability.

The best bang for the buck on a 2 stroke is always adding a good tuned pipe. Unfortunately... the exhaust on the Merc engine isn't setup to accept a pipe.