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| | | | Joined: Apr 2011 Posts: 523 Shop Shark | | Shop Shark Joined: Apr 2011 Posts: 523 | I have a 1955 235 engine in my truck. It has a Rochester B series carb, auto choke. The choke is presumably close to correct setting. The sheet metal over the engine is not yet in place so I keep a PVC pipe cap over the carb throat, leaving about 0.1" clearance between the carb throat OD and the pipe cap ID. In order to get the engine to start and run well, cold or warm, I need to leave the pipe cap ON THE CARB. If I remove it, the engine slows and dies. I have tried playing with the mixture adjustment - all the way in (lean?) has no effect, all the way out has little effect. Note - the air cleaner is not on the carb for any of this.
Bob
BobS46
| | | | | Joined: Jul 2000 Posts: 2,191 Insomniac | | Insomniac Joined: Jul 2000 Posts: 2,191 | Sounds like you need a carb rebuild kit.
Gord 🇨🇦
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1954 1/2 ton 235 4 speed
| | | | | Joined: Dec 2008 Posts: 1,922 'Bolter | | 'Bolter Joined: Dec 2008 Posts: 1,922 | The choke is presumably close to correct setting.
I would never assume that.
Correct always begins with the choke blade completely closed with the engine cold (off at least 4 hours), and with this carburetor open 9/64" (.141") measured from the edge of the choke to the throat ID when the engine starts. If it doesn't close all the way, or opens to more than .141" it will be too lean. | | | | | Joined: Nov 2002 Posts: 2,765 Carburetion specialist | | Carburetion specialist Joined: Nov 2002 Posts: 2,765 | If this carburetor has an automatic choke, would suggest at least checking the adjustment: http://www.thecarburetorshop.com/Automaticchokes.htmA choke out of adjustment would cause your symptoms. Jon.
Good carburetion is fuelish hot airThe most expensive carburetor is the wrong one you attempt to modify. If you truly believe "one size fits all," try walking a mile in your spouse's shoes!The Carburetor Shop | | | | | Joined: Apr 2011 Posts: 523 Shop Shark | | Shop Shark Joined: Apr 2011 Posts: 523 | From Panic:
Correct always begins with the choke blade completely closed with the engine cold (off at least 4 hours), and with this carburetor open 9/64" (.141") measured from the edge of the choke to the throat ID when the engine starts. If it doesn't close all the way, or opens to more than .141" it will be too lean.
Not sure that I understand this. Let me rephrase and correct me if I am wrong. Engine off, cold, choke should be closed, presumably with the choke spring under just enough to cause this. When the engine is started, the intake vacuum, operating against the choke spring force, will cause the choke to open to less than .141"
Bob
BobS46
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