Hows it goin
Just a quicky
I got the initial timing sorted on my 253 UC so the thing starts. Now this engine came from a commodore. It has a Stromberg WW on it. I ran a carby kit through it and installed it back onto the engine.
First things first, I notice a couple of linkages that should connect to the automatic choke butterly are missing (which in turn makes the choke all floppy, it basically stays open with gravity).
When I crank the engine it starts (while pumping accell) but it wont idle.
When I hold the choke butterfly closed it starts and idles. The second I let go, or open it up more than 10% it stalls straight away.
Any ideas? Im thinking its got something to do with the automatic choke, but even after warming the engine up for a couple minutes it still stalls when the butterfly is open. Ive tried with the mixture screws but nothing seems to work. Is it taking in too much air??
Cheers
Engine stalls when choke open
Started by
UCANG
, Dec 06 2011 08:41 PM
5 replies to this topic
#1
UCANG
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Posted 06 December 2011 - 08:41 PM
#2
r2160
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Posted 06 December 2011 - 08:46 PM
From what you describe, it is running really lean. If you close the choke and it goes, you are reducing the amount of air you can mix with the fuel, therefore it is lean. That could also mean that there is an air leak as well.
cheers
Glenn
cheers
Glenn
#3
UCANG
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Posted 06 December 2011 - 08:51 PM
I should get some carby cleaner and test for leaks around the place hey? Even on the manifold?, there seems to be a plate on the manifold next to the carby and just next to the coil that has one bolt missing and some silicone residue... Might have to suss that out
#4
_Gunmetal LH_
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Posted 07 December 2011 - 01:33 AM
Check to see if your manifold has any vac tree's. Check that any of the smaller tubes have been opened and not blanked off.
My LH was a prick to start, had a massive 'hole' on takeoff and when warmed up would rev way too high. Found by poking around with a matchstick that my vac tree had 2 of the outlets (inlets?) drilled out but not capped off.
Some time later I found 2 bits of thin hose with ball bearings blocking them. Probably blew off during a backfire?
Your engine being out of a commodore has probably got a tube for a factory vac/economy gauge in No.7 intake runner? Check that isn't leaking too.
My LH was a prick to start, had a massive 'hole' on takeoff and when warmed up would rev way too high. Found by poking around with a matchstick that my vac tree had 2 of the outlets (inlets?) drilled out but not capped off.
Some time later I found 2 bits of thin hose with ball bearings blocking them. Probably blew off during a backfire?
Your engine being out of a commodore has probably got a tube for a factory vac/economy gauge in No.7 intake runner? Check that isn't leaking too.
#5
UCANG
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Posted 28 December 2011 - 04:13 PM
i might have made some progress today.
I held the choke open and started her up, and it was idling like I mentioned before.. but.. stupid me, isnt a car meant to idle pretty high with the choke on? No, it was idling at a low rpm (like you would when your sitting at the lights) so I thought, duh... maybe I should turn the idle speed up, so when its on choke it idles high, and when its off choke it drops down to a normal level.. It seems it runs on its own with the choke off now.. (a bit rough, but I need to tune her up abit)
Does that make sense? the idle speed was set too low, which made it so when the choke was on, it idled like a car should do, and when its off, it drops so much that it dies?
I held the choke open and started her up, and it was idling like I mentioned before.. but.. stupid me, isnt a car meant to idle pretty high with the choke on? No, it was idling at a low rpm (like you would when your sitting at the lights) so I thought, duh... maybe I should turn the idle speed up, so when its on choke it idles high, and when its off choke it drops down to a normal level.. It seems it runs on its own with the choke off now.. (a bit rough, but I need to tune her up abit)
Does that make sense? the idle speed was set too low, which made it so when the choke was on, it idled like a car should do, and when its off, it drops so much that it dies?
#6
EunUCh
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Posted 28 December 2011 - 06:00 PM
They should idle higher with the choke on because there is a stepped cam on pass. side of carb that
is connected by a lever from choke plate shaft,there is usually an adjustment screw that you can adjust
for "choked" high idle.
As has already been mentioned make sure you have no vac. leaks at all,by the description of that plate
you mention,does it have 2 small holes in it? If so i think they had something to do with drawing hot air
into the auto choke assy. and if you take the choke cover off i think there is a hole that goes straight in to
the bottom of throttle plates.The hot pipe screws onto the auto choke cover.
I would have thought if the curb idle was set too low that the throttle plates would be below the idle fuel disharge
port and this would cause a problem,,i.e. not enough or no fuel.
is connected by a lever from choke plate shaft,there is usually an adjustment screw that you can adjust
for "choked" high idle.
As has already been mentioned make sure you have no vac. leaks at all,by the description of that plate
you mention,does it have 2 small holes in it? If so i think they had something to do with drawing hot air
into the auto choke assy. and if you take the choke cover off i think there is a hole that goes straight in to
the bottom of throttle plates.The hot pipe screws onto the auto choke cover.
I would have thought if the curb idle was set too low that the throttle plates would be below the idle fuel disharge
port and this would cause a problem,,i.e. not enough or no fuel.
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