Not sure what you mean Cecil, "one carburetor appears to be putting out twice as much fuel as the other", are you referring to the stream you're seeing in the throat from the accelerator pump????
Hey Jerry, I must be having over carburetion problems also, the problem that Cecil describes is exactly right down to the last word the way my 216 acted and now acts even after extensive work with several meticulously rebuilt Rochester 'B's. I know a lot of you guys have seen the detail that I go into with my projects. This summer I switched to a, meticulously rebuilt Carter W-1 and you guessed it, same exact symptoms. All the carburetion that I've tried on this stock engine reacts exactly the same; it runs the best and accelerates the smoothest when the choke is out 3/8-1/2 inch. Don’t need nor want to use the choke at idle though, every thing is normal at idle. The problem is definitely; more air, not enough fuel.
No problem with heat here either, completely stock and the heat riser works like a charm. And for the umpteen billionth time, I’ve completely rebuilt and all new parts in the ignition system and the ignition timing has been tried all over the place and always ends up running best back on the ball.
I know this is getting desperate, but I haven't had the front of the engine off yet so I don't have any idea whether the cam timing may be off some from a worn gear. I wouldn’t expect this to create this symptom but nothing would surprise me at this stage.
Sure wish some one would come up with a logical reason for the hesitation syndrome. Over these past two years that I've been active on the forum, the guesses that I’ve read are all over the board, from soup to nuts.
And,,,,the theory that I had about the 10% blended alcoholic gas causing a lean condition, well, that doesn't come out in the wash either. I finally got a chance to test it out, taking a chance of a $10,000 fine for running leaded gas in a road vehicle here in Illinois, I recently tried 5 gallons of an aviation 98 octane non alcoholic fuel, after 50 or 60 miles of testing out on the highway and in town traffic I find that it still hesitates just as bad and still runs it's best with the choke partly pulled out. And as odd as it may seem I really believe that the Rochester ‘B’ performed a tiny bit better, that is, except for the fuel weeping through the gaskets and staining the carb on a constant basis!
Now I know I'm gonna hear that the accelerator pump isn't working, it is, and that the high speed passages are dirty, they are not, and that the timing should be set to 35°, it's been there and it’s not, and that the float level is not set properly, or the metering rods not set, and on and on but all of that has been attended to with fanatical detail and at great expense.
There isn’t much more that I can come up with and my next step is, over the winter to do a complete rebuild of the short block, bored, new pistons and a new cam and gears just to make sure that the foundation is sound.
The really difficult part for me is, it’s been over 40 years since I’ve ridden in or driven another Chevy 6 so I’ve got nothing to compare to. But from what I can remember from my youth when I had and drove many Chevy inliners, they were pretty smooth runners.
Denny Graham
Sandwich, IL
Last edited by Denny Graham; 11/09/2008 1:13 PM.
