Compression tests

[Snow Guy]

When doing compression tests should you hold the throttle wide open or not at all?

 

[papajake]

wide open no less than 3 full pulls for best results do cold take reading, then add small amount of oil in cylinders pull 3 times take readings, then start and let warm up take readings compare the cylinder pressure should not be less than 10-15 lbs difference. if the pressure from cold to hot or oil in cylinder is more than 15 lbs ring job. if you are working on a ski doo 670 it could be your rotary valve

 

[RGM]

Doo a crank run out while you are at it.

 

[Snow Guy]

What is the reason for holding the throttle wide open?

 

[tex78]

What is the reason for holding the throttle wide open?

Cause ya need air to have compression