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#1
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ThermoQuad Question
Have friends out camping near us :They have a 1975 motor home 440 4bbl Thermoquad carb. They said that ,when they stick their foot in it . The engine stumbles and bletches out black smoke.When they ease into the pedal the speed picks up slowly.
I looked at the carb and it looks fairly new/rebuilt. I sugested that they check the filters on the carb and the two at the tanks. I was also told that this was the first trip this year, and they did not flush or add stable to tanks over winter. Just wondering if I help them flush the fuel in tanks if it would get rid of any moister and /or rust. Any thoughts would be helpful ... Thanks everyone |
#2
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Black smoke? OIL, rings, rich, stumble, incorrect pump shot, secondarys opening to fast, wrong spring in it.
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#3
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Thanks rumbblefish 360; The ideas will give me ideas where to start. My concern about the fuel being dead was ,because they told me that last year the moble home run like a top. When I seen it this morning the smoke loked dark grey. Thanks rumbblefish . When I felt spring tension on secondary plate it felt Very week. Maybe not adusted properly ? just a thought..
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#4
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tighten up the air door a 1/4 turn at a time until the bog is gone
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#5
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fun in the sun
Changed fuel filters, two on tanks and one in carb (that one I got from a carb in the garage). Found lots of rust and shit in lines,cleaned as best I could at park. Tighten air door ,just till closes plus two turns.
Friends said they would get it tuned up when they got home,later in week. Seems to run a little better,though didn't take for a road test.Sucking gas in this heat is not funn. Thanks for all the help guys, I hope this works out for them. |
#6
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I wouldn't coment but I have seen that before!
Stumbles and belches black smoke. A company I worked for had a '88 Ram Van w/318. After about 200K miles you could put your foot on the gas and fill the parking lot with BLACK smoke.
A fun thing to do was to line up the tail pipe with someone in a small car with the driver side window open. Pop the van into neutral and stomp the gas petal. The van would BLAST black smoke like a coal fired steam engine. It was a mean thing to do but it was so damn funny we couldn't resist. The 318 finally gave up and after it was yanked out and tore down it was discovered that one of the pushrods actually wore through a rocker on one cylinder. A exhaust valve was barely opening if at all. This caused a huge carbon build up in the exhaust system hense the black smoke. |
#7
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Something else you might check is the slow opening diaphram. Its located on the back corner of the carb on the opposite side from the throttle lever. If this has failed the secondary air door will flop wide open on the opening of the secondaries and cause a stumble and also the over rich condition.
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#8
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We're going out there for supper tonight, hope it cools down a bit. But I will check that diapham, They said they are heading home in a day or two ,Just want to help them make it home with lease amount of problems. My guess is the engine is just old and tired and needs to be overhauled.When our friends get home they said they would get it tuned up. Will check it out again tonight, to see if I've overlooked anything small . Thanks for the replies. This board and the people have been a great help.... Jimm II
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