[ROVERNET - UK] Calling Rovernet Brain trust!!!

[Paul Smith]

SUs are easy, easier than fixed choke carbs.
The economiser is meant to lean the mixture on cruise by applying some vacuum to the float bowl, reducing the pressure feeding the fuel to the jet when the Bernoulli force is applied (via lateral pressure reduction in the air stream through the variable venturi, aka under the piston).
I doubt it will be strong enough to cause Ben's symptoms, but we will see.  Wait for the next thrilling instalment of "The P5 on PEI vs the Owner."

PVS

-----Original Message-----
From: rovernet-bounces at lyris.ccdata.com
[mailto:rovernet-bounces at lyris.ccdata.com]On Behalf Of Kent Kinard
Sent: Friday, 29 September 2006 12:30 pm
To: rovernet at lyris.ccdata.com
Subject: Re: [ROVERNET - UK] Calling Rovernet Brain trust!!! 


Very interesting...I have much to learn about SU's.  Thank 
you, John.  This may explain some tuning problems with the 
3L7 in my P4.  I will have to check all the areas 
mentioned.  Rovernet to the rescue again.  Hope some of 
this works for you, Ben.

Rovereeducatedly,
Kent K.

On Thu, 28 Sep 2006 17:28:56 -0700
  "John Burkhard" <burkhaj at earthlink.net> wrote:
> Hi Ben,
> 
> I have looked at the factory workshop manual, the Wade 
>S. U. book and the P6 shop manual in detail.  I think I 
>may have found the problem(s).  Your car, as do all NADA 
>P5s, has an economizer (Rover term) or weakening device 
>(S.U. term).  This is mounted on top of the float bowl by 
>the center bolt that holds the cover on.  This valve 
>system regulates or controls the float chamber air vent 
>with ported vacuum. One end of the regulator valve has a 
>line going to the top of the SU throttle chamber next to 
>the vacuum advance line to the distributor.  At the other 
>end of the valve there is a hose that goes to the air 
>cleaner elbow at the carburetor.
> 
> Remove and very carefully disassemble this valve.  There 
>are a few, very small parts in this assembly so try to 
>remember where they all go.  It looks like you will need 
>to soak the valve casting in a good carburetor cleaner 
>and use lots of compressed air to give it a good 
>cleaning.  Let me know how this works.  jb
> 
> 
> ----- Original Message ----- From: "Ben Rodgers" 
><irishrover at netscape.ca>
> To: <rovernet at lyris.ccdata.com>
> Sent: Thursday, September 28, 2006 11:07 AM
> Subject: Re: [ROVERNET - UK] Calling Rovernet Brain 
>trust!!!
> 
> 
>> Hi Guys
>>            I need help! The Rover has me stumped (1967 
>>P5  Mk3 Std )
>> The car starts and idles okay with full choke on , but 
>>once underway I 
>> can
>> hardly get out of second gear and continue to need 
>>choke. >
>>
>>
>>
>>
>> FREDERICK  (BEN) RODGERS
>> born in Belfast, Northern Ireland,
>> Author of "lily and me" a great book and a great read .
>> Order on line at amazon.com. Book # ISBN1-55430-019-3
>>
>>
>> _______________________________________________
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> 
> 
> 
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