The V8 Owners Forum -

3 screw throttle pot, fueling issues above idle, clears at 4k, some erratic voltage readings so looking to replace. I understand that these are no longer available, any suggestions for a supplier?

The pdf available from this link explains possible repairs to your item, that work, especially the one where the contacts are relocated.

http://www.vintagemodelairplane.com/pag ... Pot01.html

also details of a low cost replacement if you have home workshop skills.

Thanks Ramon, I've had a good read through your website, unfortunately I struggle with smaller components so I'm hoping that there is a straight swap but this is looking increasingly unlikely.

The pot measured 0.22v with throttle closed, adjusted to 0.34v and there is improvement, but still flat spots, if I adjust to 0.4v with throttle closed is there a risk of over-fuelling?

Fed_up_Stag-owner wrote:Thanks Ramon, I've had a good read through your website, unfortunately I struggle with smaller components so I'm hoping that there is a straight swap but this is looking increasingly unlikely.

The pot measured 0.22v with throttle closed, adjusted to 0.34v and there is improvement, but still flat spots, if I adjust to 0.4v with throttle closed is there a risk of over-fuelling?

I can sell you a replacement pot as per Ramon's article for 50 quid inc postage.

Just made up another batch. ;-

Hello Fed-up, the base throttle pot setting at the margins being discussed, will have very little if any effect on fuelling across the range, the TP's primary purpose being to inform the ECU of the rate of change in throttle position for acceleration enrichment, and when to apply full load enrichment.

So why 0.325 volts? In simple terms, its just a low point on the pot (not zero which is far too uncertain) from which everything else can be trusted. 0.4 is inconsequential. 1.4 would defo affect full the load enrichment point of 3.3 volts, bringing it in much too early.

hope this helps?

Thanks Ramon, the flat spots feel like a carb running without the accelerator pump, at least until 4kish and then it goes well (full scale voltage on the pot = max enrichment)

I'll fettle at the weekend but a new pot is probably the permanent solution.

Throttle pot tracks are heavily worn and beyond my skills to fettle, although I can see how the various workarounds can be achieved. I'll try and get a reasonable photo, first attempts have poor focus.

Throttle pot from DaveEFI now installed, things much improved but still some hesitation at light throttle loadings (so probably not throttle pot related), next stage will be to inspect the tracks on the AFM, assuming no air leaks found.