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I have a 1977 vogue class c motorhome that I have owned for several years. Up to this year it has ran great, even pulling 10,000 ft. passes. It is now bogging down and cutting out like it wants to die when I put my foot into it. I have gone through the fuel system, replaced filters, fuel pumps, mechanical and inline electric. Dropped the gas tank to check for a clogged filter sock, the only thing I haven't done to this point is the carb. (thermquad). I suspect this could be the problem since everything else has been replaced. I thought before I spend the money for a rebuild or replacement I would ask for advice. I also did a complete ignition tune-up, new wires,rotor,cap,plugs,etc.
The T-Quad's secondaries are controlled by the choke "cracker"( a vacuum operated "can" which "cracks "open the choke blade as soon as the engine starts,after that, the choke opens slowly in responce to heat being applied to the choke control ). The air doors have an internal spring which wants to close them, the vacuum cracker/air door controller wants to open them in responce to increased ported vacuum. There is a tiny vacuum supply hose that runs down to near the base of the carb, where it fits onto a small nipple. If the passage to that nipple plugs up, the secondaries, nor does the choke, operate as designed. Locate that nipple, disconnect the hose and check for vacuum. Before you do that, however, remove the "dog house", remove the lid of the air cleaner, start and warm the engine, using a mirror---in case of back fire, ( that's flame out of the carb, explosion in the exhaust system is "after burning")--, to look down into the throat of the carb to see if the choke is fully open. If it is, then accelerate/decelerate the engine, the step-up rod link should rise and fall. If that checks out OK, then momentarily floor the gas pedal, the air doors should open a little in responce to the increased throttle opening. If you can have someone check on the air door operation while you drive the rig, all the better. If the choke is not fully opened, the "secondary lock out" will prevent the seconary throttle plates from opening.
Your best bet is to replace it with a holly unit of about 550 or better no bigger than a 650 it will flud the motor. also any thing under 450 hp should only have a 550 so its up to you with how you fix your problume but you will gain horse power with this carb electric choke
email b hedrick
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