[TR] Issues with Temp. compensators on a ZS CD 175

[Bud]

Sujit,
Having boiled my temperature compensators and trying to get them perfect I went down that rabbit hole for quite some time. 
I found that the same problem you have actually was caused by too high fuel pressure. 
My problem went away when I installed a fuel pressure regulator in the gas line between the fuel pump and the carbs . I hooked up a vacuum/ fuel pressure gage simultaneously and set the fuel pressure to 1.5-2 psi. Basically ZS carbs will flood just a wee bit by the float valve not being able to hold back fuel any higher pressure  than that. Hence higher RPMs once warm with the extra fuel.
One indicator of this is a Triumph that needs little or no choke to start up when cold. These cars were designed to be choked on most.

Bud

Sent from my Commadore 64

> On Jan 18, 2022, at 10:20 AM, Sujit Roy <triumphstag at gmail.com> wrote:
> 
> 
> I've been running into issues with my ZS carbs. The problem is as the car gets to operating conditions, the RPMs goes up from about 800 rpm  to about 1000. 
> I have carbs with by-pass valves, but they are blocked off.
> Folk have said it's the temp. compensators. I rebuilt the carbs and have adjusted the compensators according to an article on Buckeye Triumph. Suggestions have been to tighten the adjustment screw so they don't open. 
> 
> So I have just read the Dealer Training on the subject of Carburetion. I see how the compensators work and make the fuel mixture leaner when at operating temperature. The doc says when they open, it weakens the depression which allows the piston to fall slightly thereby cutting the available fuel and creating a leaner mixture. This I get, but with the throttle plate in the idle position, and the volume of air passing the throttle plate can't change, then why does the engine speed increase?
> 
> 
> Regards, Sujit
> 
> -- 
> Sujit Roy
> Cupertino, California
> 
> https://triumphstagblog.wordpress.com/
> 
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