V8Pete Posted November 3, 2015 Share Posted November 3, 2015 I've got a bog standard 3.5 V8 running on SU carbs. I recently rebuilt the carbs with the full rebuild kit and set them up according to the official manual and it all starts and runs well except for one problem. After a long run the idle speed increases to about 1,200 rpm. If I turn the engine off for a minute and start it again it's fine. And it idles normally at all other times, it's only a problem after a long run on main roads/motorways. It doesn't appear to be a sticking throttle as I've checked that both throttle levers are on the throttle stop screws . I put in new throttle disks and left the overrun valves in place so I guess it could be one or both of these sticking open. Any carb gurus out there with some ideas of what could be causing this problem? Thanks Quote Link to comment Share on other sites More sharing options...
Landrovernuts Posted November 3, 2015 Share Posted November 3, 2015 Solder the overrun valves closed or replace the butterflies with plain ones not fitted with them and I would bet your problem stops. From what I remember it was a known issue. Quote Link to comment Share on other sites More sharing options...
V8Pete Posted November 4, 2015 Author Share Posted November 4, 2015 Thanks. I think I'll have to give that a go. It didn't suffer the same problem with the original butterflies in place but maybe the springs had stiffened up enough for it not to be a problem. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.