Yes JD, the heat riser is nessasary for a smooth running engine, inspite of what some are going to tell you. Other wise General Motors would not have wasted money putting one on every engine that they made.
Has anyone messed with the heat riser bias spring by any chance?
Looking at the heat riser weight from the front, when cold the spring should be holding the weight all the way in the full clockwise position. As it warms up it will allow the weight to rotate to the open or counter-clockwise position.
Denny Graham
Sandwich, IL
