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Re: Interesting Carb Problem

To: Roadster List <datsun-roadsters@autox.team.net>
Subject: Re: Interesting Carb Problem
From: Ronnie Day <rday@hot.rr.com>
Date: Sun, 02 Nov 2003 17:12:42 -0600
> As I said in another post, I installed NOS 2L carb bodies on my car. Now
> there is resistance to the butterflies opening as if vacuum is forcing the
> butterflies to remain closed. I really have to press the pedal to overcome
> this 'force' which results in my car behaving like a rubberband after the
> initial resistance is overcome and the carbs really open up.
> 
> Nothing is binding and when the engine is not running the accelerator action
> is as smooth as silk.
> 
> Today, prior to a rally I participated in, I asked several MG/Triumph
> mechanics and 'Mr. SU', Joe Curto, about this problem and it has all of us
> stumped. Since my Datsun was there we tried all kinds of fixes to no avail.
> 
> I noticed several problems with these NOS carbs and fixed them prior to
> installing them.
> 
> Any answers out there? I Googled everyone.

Mike, I don't see engine vacuum having any effect at all on the butterflies.
At least it shouldn't. It sure sounds like something is binding. Is the
resistance evident both with the engine off and running? If it's only with
the engine running I'd guess is that after the engine's started something
moves enough to create a problem.

I'd isolate the gas pedal and linkage from the linkage that ties the two
carbs together, and then check both carbs individually for free throttle
shaft rotation. Maybe something's caused a crimp or a kink in the throttle
cable?

FWIW,
Ron

Ronnie Day
rday@hot.rr.com
Ronnie_day@acd.org
Temple, TX
***********************
'71 510 2-dr (Prepared Class Autocrosser)
'73 510 2-dr (Street Toy)





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