Low vacuum on carb

Technical questions and answers
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Matt1
Posts: 30
Joined: Tue Sep 18, 2018 6:48 pm

Low vacuum on carb

Post by Matt1 »

Hi. I can’t get my rover 3.5 v8 to idle.Theres loads of vacuum on the near side carb but very little on the offside carb.It has zenith carbs fitted.could it be an air leak that causing low vacuum and are there any common places that it would leak from?i tried a search but couldn’t find an answer. Thanks Matt
map1275
Posts: 1076
Joined: Mon Jul 21, 2008 2:48 am
Location: Brisbane, Australia

Re: Low vacuum on carb

Post by map1275 »

Is the piston sticking?
Or (although rare) has the diaphragm split?
Matt1
Posts: 30
Joined: Tue Sep 18, 2018 6:48 pm

Re: Low vacuum on carb

Post by Matt1 »

Thanks. They’re ok. Going to get it smoke tested.
udo1-ton
Posts: 33
Joined: Fri Nov 28, 2014 3:59 pm

Re: Low vacuum on carb

Post by udo1-ton »

If there are later carbs fitted, there should be an additional spring loaded valve fitted in the throttle valve. When the spring got weak over the years there is an bypass at idle revs. The best solution is an exchange to the standard unit without valve or the valve can be soldered.
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Regards
Matt1
Posts: 30
Joined: Tue Sep 18, 2018 6:48 pm

Re: Low vacuum on carb

Post by Matt1 »

Ok. Thanks for your help
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