99 venture 600 smokes - Snowmobile Forum: Your #1 Snowmobile Forum

duckmanlabs · 10-28-2009, 03:08 PM

I have a 99 venture 600. When idleing its fine but when i give it some throttle it smokes.Kind of looks like a car does on a cold day till it heats up (the car that is). The smoke is thiker than just condensation and hangs in the air with a blueish gray color. I have adjusted the throttle and oil pump cables,changed the gas, cleaned and checked the carbs. the spark plugs insulator looks like used motor oil cooked on it. Usualy fouls the plugs before a few hundred miles. The sled was bought new in 99 always seviced by the dealer, who said it was normal to smoke like that.Compresion on all 3 cylinders is 140psi. Hope I explained enough thanks for any help.

**RJ Gleason** · 10-28-2009, 03:31 PM

It's a two stroke, that's what they do.

**BC_Dan** · 10-28-2009, 03:39 PM

Welcome to the forum!

It's pretty normal for a sled to smoke for a while until things warm up, and to put out quite a bit of smoke at start up. Some plugs are more likely to foul than others, you may want to try a different brand. Some oils smoke more than others, as well. It is also common for the plugs to have burned oil on 'em, that actually can be an indicator to aid in tuning. If the plugs are black, you are burning rich, if they are white, you are burning lean. You should jet the carbs so that the plugs have a cardboard brown color to them.

When the engine is idling, oil/gas enters the crankcase to lubricate the bottom end. A lot of the oil condenses on the bearings, crank, and crankcase as intended, but because of the low velocity of airflow through the crankcase, oil can accumulate. When you increase the throttle, the increased velocity of the airflow picks up some of the left-over oil and carries it into the cylinders along with the normal oil/fuel/air so until the extra is "vented" out of the crankcase, the engine smokes more than normal. You can minimize this by keeping idling to a minimum.. for example, when warming the sled up at the start of the day, idle until there is heat in the rear exchangers and then shut down until you are ready to ride.