Post by djm16 on Nov 11, 2018 22:53:22 GMT
Has anyone else noticed this? This is most apparent with my P4 90. To get the H4 carb mixture even within range of normal (it was always too rich) I had to lower the needle from the usual set position of flush to about a 1mm shoulder showing. Any lower than that and the shoulder makes contact with jet and hold the piston up.
Yes, of course there are other possible causes of rich mixture at WOT including worn needle and jet (both new and checked for accuracy), and carb float level (also checked and lowered). Note that the economiser has no effect at WOT.
So with the benefit of a AFR meter (everyone should have one or at least have access to one
I periodically check my mixture. A couple of months ago I noticed first lower mpg and when I checked the AFR, I found I was running rich again. I mean really rich. To even get back into range at WOT with my jet fully up, I had to lower the jet a full 2mm from the piston. Then enable the piston to lower range than being held up by the needle shoulder resting on the jet, I had to file off 2mm of the shoulder on the needle.
So does anyone else think that petrol viscosity in Western Australia is lower than say a year ago? I have already noted here before that specific gravity of petrol today is lower than say 50 years ago. I don't remember where I got my data, but it would have been on the internet. That was when I was investigating why my intact and original brass float would not (float in petrol).
Yes, of course there are other possible causes of rich mixture at WOT including worn needle and jet (both new and checked for accuracy), and carb float level (also checked and lowered). Note that the economiser has no effect at WOT.
So with the benefit of a AFR meter (everyone should have one or at least have access to one
I periodically check my mixture. A couple of months ago I noticed first lower mpg and when I checked the AFR, I found I was running rich again. I mean really rich. To even get back into range at WOT with my jet fully up, I had to lower the jet a full 2mm from the piston. Then enable the piston to lower range than being held up by the needle shoulder resting on the jet, I had to file off 2mm of the shoulder on the needle.So does anyone else think that petrol viscosity in Western Australia is lower than say a year ago? I have already noted here before that specific gravity of petrol today is lower than say 50 years ago. I don't remember where I got my data, but it would have been on the internet. That was when I was investigating why my intact and original brass float would not (float in petrol).