Question:
Hello,
In the 1/10/07 article, Kent Lester mentioned something about jetting the 600 HO Fusion, carefully.
Could you give me more info on this. I have one of these sleds and have a problem with bogging down at cold start-up. Will this help me?
John Janssen
Response:
John:
Polaris carbureted 600HO engines use both a throttle position sensor and a knock sensor. The TPS reports the rider’s demands on the engine and communicates with the knock or detonation sensor.
Knock sensors enable the engine to run much leaner with stock jetting (ie: the stock jetting is set much lower from the factory than with a non-knock sensor engine).
The knock sensor basically tells the engine’s control unit to either advance or retard the timing when the engine is too lean or too rich. (advance when rich, retard when lean).
A bog usually indicates a too-rich mixture (timing retarded) and this may be a timing setting Polaris has programmed-in when the engine is first started so you don’t cook a cold engine.
I know some owners have leaned out their mains a size or two (depending on elevation) on this sled with good results but the net gain may not be worth the risk depending on how you ride.
If you run big lakes at wide-open throttle you could be running too lean up top too long. If you’re trying to beat someone in a drag race, running short bursts at WOT, the leaner settings may work for you.
You may just want to try being more patient, letting the sled warm up completely and let the electronics do their thing.
Kent Lester
