[Hurst65]

Originally Posted by Dick Boneske

If you adjust to 14.5 -15.0 and then open the throttle, the accelerator pump squirt would have momentarily richened the mixture. If you do what you describe and then wait a minute or so, does the reading return to 14.5?

It's surprising that the .060" jets show too rich a mixture while driving. Maybe there is not enough vacuum to keep the power valve closed. Maybe the weaker spring on the power valve is the answer. Stock power valve spring measures 150 grams on the setup I use to check them. If you remove 8 turns of a stock spring, the result is about 80 grams of force to move the spring off fully extended, which is still plenty of pressure to open the power valve when vacuum goes down when the throttle is opened under load.

Keep us tuned in!!

Thanks.

No, the reading does not return to 14.5 after the pump shot. That's what's weird. It doesn't do it every time. It's very random. Something funny is going on and until I figure that out I'm going to be chasing my tail. I'm thinking it's the power valve. What else could it be?

I agree with your thoughts on the 60's. I think I'll put the 63's back in tomorrow. I don't have data to back it up but, I think the 63's felt better. My seat-of-the-pants meter liked the 63's better.