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| | | | Joined: Sep 2004 Posts: 241 'Bolter | | 'Bolter Joined: Sep 2004 Posts: 241 | I have a 235 six. A friend gave me a remanufactured Rochester B for my truck. The float level was set to specs. The only thing that I replaced on this carb was to add a .055 jet in place of the .051 jet that was in there. I was able to get 19” in vacuum and set the idle at around 650. Everything seemed fine.
It drove real nice around town but I noticed the idle would keep going down at every stop light. A smooth idle but it would get lower and lower. After I got it home I tried to restart it after 10 minutes and it would not start at all. It wasn’t leaking and I didn’t smell gas.
I ended up taking this carb off and putting my old “B” back on. Is it possible that the power piston is sticking or maybe a faulty idle mixture screw? I checked the power piston and it moves freely. All other non carb settings on my truck have been checked. Dwell is around 30 and the timing is set at 10 degrees BTDC.
Thanks for any help.
| | | | | Joined: Jul 2007 Posts: 461 Shop Shark | | Shop Shark Joined: Jul 2007 Posts: 461 | From your description, it sounds like the idle mixture is too rich. Possible causes of that condition are the idle mixture screw is incorrectly set, or there is internal leakage that affects the idle mixture. Try setting the idle mixture screw a half turn in (lean). If you set the mixture screw for the highest idle vacuum, it is easy to turn the screw out (rich) a half turn or so without affecting the manifold vacuum. Also, if you set the mixture before the engine reached normal operating temperature, you could have the mixture set too rich for the hot idle.
Harvester | | | | | Joined: Sep 2004 Posts: 241 'Bolter | | 'Bolter Joined: Sep 2004 Posts: 241 | I backed off the idle mixture a bit when I reached a good vacuum reading. I thought that I was in there.
You're probably right. It most likely is running too rich and flooding. I'm used to seeing these Rochesters leak at the gasket when they flood. This one didn't. I need to tinker some more with it to get it right. Thanks Harvester.
| | | | | Joined: Jan 2009 Posts: 1,644 Shop Shark | | Shop Shark Joined: Jan 2009 Posts: 1,644 | MarkT where did You get the jet?
Pete | | | | | Joined: Sep 2004 Posts: 241 'Bolter | | 'Bolter Joined: Sep 2004 Posts: 241 | Pete - A place called Allstate Carbureter. They are located somewhere in NY. They had jets for the B and BV. They are on Ebay. The jet works fine. Sometimes you never know if they are marked correctly. | | | | | Joined: Apr 2006 Posts: 506 Shop Shark | | Shop Shark Joined: Apr 2006 Posts: 506 |
-Tom
1950 Chevy 3100 w/ 1956 235
| | | | | Joined: Jan 2009 Posts: 1,644 Shop Shark | | Shop Shark Joined: Jan 2009 Posts: 1,644 | Thanks, could not find a carter 2100s so I rebuilt the B that came on the 216 (high top)was in the truck and used the base of the B that came on the 235 power glide engine(early version) that I just put in My truck, somone had drilled the jet on the 235 carb so the truck was running real rich now it's running alittle lean so I'd like to get a few jets and see if I can find the best mix.
Thanks again,Pete | | |
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