Wilsons Sandbox

I'm having trouble getting idle speed down under 1200 RPM and looking for advice. This is on a newly rebuilt, tight engine. Tappet clearance is set correctly. Points set correctly, dwell is good. Advance is 5 degrees BTDC. Fuel mixture appears okay (plugs are brown after 40 miles, and I followed what I think is correct adjusting methods). Idle speed screws adjusted completely out. Mixture control and slow running controls are neutral. What else should I look for? I'm wondering if the butterfly isn't fitting the carb throat properly (a warped carb)? Thanks for any advice. Tom Wilson TWilson@Motionwear.com> TC4378 idling too fast TC0272 chassis almost done, tub mostly done TC0273 in a sorry state, waiting for resurrection

Remove the linkage between the carbs. Take the carbs off the engine. Sight down carbs with throttle plates closed to check for the warpage you mentioned. COrrect if necessary Make sure there are no air leaks between the carbs and manifold, and between the manifold and the head. Engine oil on the joints will often reveal this leak. Put carbs back on the engine. If all this checks out, back out the idle screws completely and start the engine. It should die out from lack of air/fuel. If it does, screw in both idle adjusting screws equally until it will idle. Now synchronize the carbs with a unisyn or similar tool. Now reconnect the inter carb linkage. Make sure you hold both throttle shafts down tight against their stops while you do this. Report back to the list! -TC 7881 Tom Wilson twilson@motionwear.com> wrote: I'm having trouble getting idle speed down under 1200 RPM and looking for advice. This is on a newly rebuilt, tight engine. Tappet clearance is set correctly. Points set correctly, dwell is good. Advance is 5 degrees BTDC. Fuel mixture appears okay (plugs are brown after 40 miles, and I followed what I think is correct adjusting methods). Idle speed screws adjusted completely out. Mixture control and slow running controls are neutral. What else should I look for? I'm wondering if the butterfly isn't fitting the carb throat properly (a warped carb)? Thanks for any advice. Tom Wilson TC4378 idling too fast TC0272 chassis almost done, tub mostly done TC0273 in a sorry state, waiting for resurrection Yahoo! Groups Links -Rick Waters --------------------------------- Post your free ad now! Yahoo! Canada Personals [Non-text portions of this message have been removed]

Loose throttle shafts on the carbs. They can be reamed and replaced with larger diameter shafts. Fred TC1353 -----Original Message----- From: mg-tabc@yahoogroups.com [mailto:mg-tabc@yahoogroups.com] On Behalf Of Tom Wilson Sent: Monday, May 09, 2005 7:56 PM To: mg-tabc@yahoogroups.com Subject: [mg-tabc] idle speed I'm having trouble getting idle speed down under 1200 RPM and looking for advice. This is on a newly rebuilt, tight engine. Tappet clearance is set correctly. Points set correctly, dwell is good. Advance is 5 degrees BTDC. Fuel mixture appears okay (plugs are brown after 40 miles, and I followed what I think is correct adjusting methods). Idle speed screws adjusted completely out. Mixture control and slow running controls are neutral. What else should I look for? I'm wondering if the butterfly isn't fitting the carb throat properly (a warped carb)? Thanks for any advice. Tom Wilson TWilson@Motionwear.com> TC4378 idling too fast TC0272 chassis almost done, tub mostly done TC0273 in a sorry state, waiting for resurrection Yahoo! Groups Links

Tom, One source of this problem is the rotation of the carb shafts in relation to the position of the butterfly. This is usually caused by the butterfly not being in the closed position before attaching the idle adjustment parts. Thus, if the butterfly is open more than a few degrees when you attach the idle control parts, backing out the idle adjustment screw may have little or no effect. This is also dependent on the return spring being in the correct position. In addition to the above, follow the steps recommended by another respondent about re-setting the two shafts when installing the carbs. Good luck! Andy

----- Original Message ----- From: "Tom Wilson" twilson@motionwear.com> To: mg-tabc@yahoogroups.com> Sent: Monday, May 09, 2005 7:56 PM Subject: [mg-tabc] idle speed > I'm having trouble getting idle speed down under 1200 RPM and looking for > advice. > This is on a newly rebuilt, tight engine. > Tappet clearance is set correctly. > Points set correctly, dwell is good. > Advance is 5 degrees BTDC. > Fuel mixture appears okay (plugs are brown after 40 miles, and I followed > what I think is correct adjusting methods). > Idle speed screws adjusted completely out. > Mixture control and slow running controls are neutral. > > What else should I look for? I'm wondering if the butterfly isn't fitting > the carb throat properly (a warped carb)? > > Thanks for any advice. > > Tom Wilson > TWilson@Motionwear.com> > > TC4378 idling too fast > TC0272 chassis almost done, tub mostly done > TC0273 in a sorry state, waiting for resurrection > > > > Yahoo! Groups Links > > > > > > >

Are the carbs originals? Some of the later ones have fittings for a vacuum advance pipe, which if not sealed, plays games with carb setting. I found this out the hard way on TC1459! Regards, Mark ---------------------------------------------- This mail sent through http://www.ukonline.net