su carb problems expert needed

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Sun 31 Oct 2004 19:07
su carb problems expert needed - mikecotterill
just fitting an su to my landd rover. temporarily fitted it to see if it ran and it just started to rev. so i killed it any one have any idea what it could be? there is a picture here of a similar one anyone know what type this is for spares etc. beleive it was of an sd1. thanks all
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Sun 31 Oct 2004 19:12
su carb problems expert needed - Roly93
This probably isnt a fault of the carb. It is more likely to be a vacuum side air leak of some description, ie incorrect air seal between carb and manifold.
Also, I assume you did check that the throttle butterfly could close to almost nothing. I apologise if I am telling you to suck eggs.
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Sun 31 Oct 2004 19:26
su carb problems expert needed - mikecotterill
this is similiar looking: cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&category=...s i said it was just to see if it ran so there was no gasket between the joints also there are three fuel pipes on it. persumably one is the supply, one supplies the other carb and the other is a return. these also werent blanked off, the vacum pipe is also not connected for the dizzy as my dizzy has no vacum advance. if the butterfly was not closing fully would it only fast idle. as this was revving so much so i had to stop it. cheers for the help
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Sun 31 Oct 2004 19:40
su carb problems expert needed - Civic8
>>the vacum pipe is also not connected for the dizzy as my dizzy has no vacum advance.

Possibly your problem.Try blanking off vacuum pipe to distributer..Yours has centrifugal advance not vacuum controlled
third pipe from carbs is fuel overflow. gasket is needed on joints to prevent air leaking past joints.In effect bypassing carbs
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Steve
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Sun 31 Oct 2004 19:18
su carb problems expert needed - mikecotterill
dohh. cant find the link now. any help with the problem much appreciated though.
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Sun 31 Oct 2004 19:30
su carb problems expert needed - Civic8
Sorry could you explain more on what the problem is..Post was a little vague..Unless I read it wrong??
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Steve
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Sun 31 Oct 2004 19:40
su carb problems expert needed - mikecotterill
basically put this carb on, started it. started straight away. but started to rev up going towards full revs. not wanted to damage the engine i stopped it. could the wrong type of oil do this i used 1o 40 which although a bit thick was all i had at the time.
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Sun 31 Oct 2004 19:49
su carb problems expert needed - Civic8
Sorry we posted at the same time.What is recommended oil for it?
though doubt thats the prob..
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Steve
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Sun 31 Oct 2004 19:55
su carb problems expert needed - Number_Cruncher
On petrol engines, output is controlled (predominantly #) by regulating the flow of air into the engine, i.e., by the throttle valve. If your engine is revving too high, it is ingesting too much air. The leak / fault could be anywhere between the throttle and the cylinder.

as mentioned above, check the throttle is closing, and is correctly sprung closed.

On some SUs, there is an overrun valve incorporated in the throttle. The spring in this can fail, allowing the valve to flow air when it should be closed - this would allow the engine to rev a bit. Either block this shut, for testing purposes, or fit a solid throttle valve.

Make sure the inlet manifold is sealing correctly, and *all* take off pipes are appropriatly connected, or blanked off.

At the risk of reopening an earlier thread's argument, the oil in the carburettor dashpot is not important to you in curing this fault. Neither, for that matter is the grade of oil in the sump.

number_cruncher

# on automatic cars with modern fuel injection systems, the ignition timing is retarded during gear changes to temporarily reduce engine power and give a smooth change. This is, of course, irrelevant for this particular problem.
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Sun 31 Oct 2004 20:05
su carb problems expert needed - Civic8
Cheers NC couldnt have put it better myself
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Steve
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Sun 31 Oct 2004 21:31
su carb problems expert needed - mikecotterill
cheers will have a look tommorrow and blank of the pipes. ill let you know how i get on
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