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Old 09-04-2018, 11:15 PM
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I am back to thinking it is a blockage in a carb. I cannot find a vacuum leak. I have tried carb cleaner and propane. I am 99% sure it isn't an internal intake gasket leaking. No change when I put propane into the crankcase, but more importantly, no smoke. I would think it would smoke like a freight train sucking oil into an intake port.

The carbs are fresh and all of the fuel lines are new, but I suppose something could have made it past the fuel filter or something came out of a fuel line.
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Old 09-05-2018, 06:41 AM
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FYI I have had high readings like you describe just before the O2 sensor takes a crap, If you have a new sensor put it in and calibrate it and try to see what it reads, obviously shut down if it still reads high. I have been fooled in the past by this, more so if you have any amount of reversion in the exhaust. The Cough/Hiccup could have gotten the sensor damp. Again just another thing to investigate.
Good Luck, keep us posted
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Old 09-05-2018, 07:29 AM
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will do, thanks
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Old 09-05-2018, 08:19 AM
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Check the needle and seats too. I've seen where a piece of crap gets stuck in the needle , and blocks fuel flow partially. It can still keep the bowls full at idle, but once underway and the fuel demand goes up, the bowl goes dry.
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Old 09-05-2018, 08:31 AM
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But idle from 14 to 20:1, I don't know.
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Old 09-05-2018, 08:33 AM
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Joe, just thinking but did you completely rebuild the carbs? If so maybe you did not get the base to throttle plate screws on the bottom tight enough and are leaking air slightly there. Gotta be something small but weird in my opinion.
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Old 09-05-2018, 08:38 AM
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Do your datalogs show anything interesting from the map sensor readings?
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Old 09-05-2018, 08:45 AM
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Also, the pv not opening/ not opening wont affect idle afr. Now if it blew the diaphragm, it would go rich at idle.
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Old 09-05-2018, 09:40 AM
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I didn't have my laptop with me at the lake
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Old 09-06-2018, 06:23 AM
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one thing, you said you are using the intake for the PV vac signal...that will see pressure under boost and close off power valve, need to get vac from under carb above blower I think.
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