Here is the instructions from Holtzman:
2. Choose a Base Temperature which for snowmobiles is NORMALLY -20F (-29C), but -40F (-40C) or 0F (-18C) can be chosen depending on your minimum operating temperature. The adjusting screw target position is at the dot if you choose -20F(-29C), 1/8 turn clockwise from the dot if 0F(-18C), and 1/8 turn counterclockwise if -40F(-40C). INITIALLY, SET THE SCREW 1/8 TURN CLOCKWISE FROM THE TARGET POSITION.
Why do you start with the screw 1/8 turn CLOCKWISE from dot? Initially I thought that was the richest setting and you would work back from there but here in the instructions clockwise is for 0 degrees vs CCW for -40 degrees, isn't that counter intuitive?
Anyone just give me a layman's way to tune a set of SLP pipes on a viper after installation? Hoping to do it over holiday break. Thanks!
2. Choose a Base Temperature which for snowmobiles is NORMALLY -20F (-29C), but -40F (-40C) or 0F (-18C) can be chosen depending on your minimum operating temperature. The adjusting screw target position is at the dot if you choose -20F(-29C), 1/8 turn clockwise from the dot if 0F(-18C), and 1/8 turn counterclockwise if -40F(-40C). INITIALLY, SET THE SCREW 1/8 TURN CLOCKWISE FROM THE TARGET POSITION.
Why do you start with the screw 1/8 turn CLOCKWISE from dot? Initially I thought that was the richest setting and you would work back from there but here in the instructions clockwise is for 0 degrees vs CCW for -40 degrees, isn't that counter intuitive?
Anyone just give me a layman's way to tune a set of SLP pipes on a viper after installation? Hoping to do it over holiday break. Thanks!
yamaholic22
Active member
no that is not counter intuitive. -20 is the tempa-flow turn on temp when the screw is set at the dot. If you are jetted for -20, that is where you should have it. If you are jetted for -40, you should be at 1/8 counterclockwise, which makes the tempa flow start leaning the mixture down at -40F and up from there. Now if you are jetted for -20 and turn the screw CCW from the dot, you are using it to lean your mixture, which is fine if your plugs and piston wash indicate that is ok. You could also jet for -40 and run the screw at the dot to be REAL safe, and check pistons and plugs and lean it out from there if they indicate that is safe. Plugs and piston wash never lie, egts can if not used properly. The reason you start the screw 1/8 clockwise from your target is to make sure you are plenty rich, and then you can lean it out from there if your plug/piston readings indicate you are plenty rich.