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FSJunkie View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote FSJunkie Quote  Post ReplyReply Direct Link To This Post Posted: Jun/12/2023 at 12:45am
A fuel level that is too high can certainly cause rich problems and flooding in turns. 

The next question is why is the fuel level too high? The float could be set wrong, one of the float pontoons could have fuel in it causing it to sink, the needle might not be sealing, or the inlet seat might be leaking where it screws into the casting.

Some carburetors just need their float set lower. 1/8" lower than spec should do it. That is a lot in carburetor world. If 1/8" fixes your problems, try raising it 1/16" to split the difference. It's best not to lower it any more than you must. 
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Stingray View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Stingray Quote  Post ReplyReply Direct Link To This Post Posted: Jun/12/2023 at 2:29am
Thanks FSJunkie,

After your suggestion, I did check the floats. (plunged into extremely hot water - no bubbles)

I also installed a sight plug to verify levels not too high and needle n seat OK.

Now after lowering the float level by 1/8" (I know that's a lot but wanted to see if any real difference), the stumbling on right turns has gone away. That's good news! It drives OK in all other respects.

My next move is to run a tank of gas through it and measure gas mileage.  I'll use a GPS speedo on my phone to get an accurate odometer. (the speedometer in the car is inacurate)

My suspicion here is that the rich condition on deceleration could be a red herring, in that although it's rich there's so little fuel flowing it probably doesn't affect overall economy.

I'll let you know how I go after I've used a tank of gas.

Cheers,
Joe
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Heavy 488 View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Heavy 488 Quote  Post ReplyReply Direct Link To This Post Posted: Jun/12/2023 at 9:51am
Deceleration has high manifold vacuum against closed butterflies. The idle circuit is exposed and working hard to feed. pitfall of a carb.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Trader Quote  Post ReplyReply Direct Link To This Post Posted: Jun/12/2023 at 2:49pm
Wouldn't worry too much about carburetor fuel feed on deceleration. The engine will lean out as only idle fuel flow is being supplied to the engine. Even EFI systems provide some fuel to ensure low noise and enough fuel to have ignition in the cylinder and not a backfire in the exhaust.
An example of an engine fuel system that does not provide fuel on deceleration is the Jake Brake on a truck. It's basically compressor exhaust noise and can be quite loud.
Your also going to need to run or tune richer then the OEM specifications if burning ethanol fuel as it has less BTU and best burn of E10 is 14.2:1 AFR vs gasoline at 14.7:1 AFR. The mileage will also be approximately 10% lower then OEM specifications for gasoline due to the reduced BTU's.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Stingray Quote  Post ReplyReply Direct Link To This Post Posted: Jun/12/2023 at 9:24pm
Hi Heavy 488,

I agree with your thinking.  I'll measure fuel economy next over a tank of gas and see where I'm at.

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Joe
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Stingray Quote  Post ReplyReply Direct Link To This Post Posted: Jun/12/2023 at 9:28pm
Originally posted by Trader Trader wrote:

Wouldn't worry too much about carburetor fuel feed on deceleration. The engine will lean out as only idle fuel flow is being supplied to the engine.
Your also going to need to run or tune richer then the OEM specifications if burning ethanol fuel as it has less BTU and best burn of E10 is 14.2:1 AFR vs gasoline at 14.7:1 AFR. The mileage will also be approximately 10% lower then OEM specifications for gasoline due to the reduced BTU's.


Thanks Trader,

The exhaust gas analyser is showing rich on deceleration, 12:1,  but I'm starting to think it may not be an issue.

The fuel I'm using has no ethanol.

Beer
Joe
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Stingray Quote  Post ReplyReply Direct Link To This Post Posted: Aug/28/2023 at 1:08am
Hi All,

I've been doing a little driving since my last post.  A total of 105 miles (GPS checked) using 23.2 litres or 6.13 US gallons.

The driving was mostly city driving with a little 50mph highway stuff.

That translates to 17.2 mi;es per gallon.

What do you think of this economy?  

(A reminder - 1996 American Rogue, 232 six with BW35 auto.  Carter WCD two barrel.)

Thanks for your thoughts.

Beer
Joe
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mixed up View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote mixed up Quote  Post ReplyReply Direct Link To This Post Posted: Aug/31/2023 at 1:39am
17 MPG is not bad in the city and a little high way back in the 70s dad would get about 20 21 mpg out of the old 232 in the ramblers .I feel your looking to deep in the quest for fuel mileage just drive the car and after a few tank check the plugs and see what color they come out mean time just log the odometer reading and fuel on every fill up and check your average .believe me if there was a way to squeeze mileage out of a car dad would do it driving habit has a lot to do with it .coast more to stop signs ,ease into the throttle try running a mid grade in it    
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Stingray Quote  Post ReplyReply Direct Link To This Post Posted: Aug/31/2023 at 4:18am
Hi Mixed Up,

Thanks for your response.

I will keep a log as you suggest.

I am encouraged by your dad's experience and my mileage may well be acceptable.

Beer,
Joe
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