My 84 RX7 (carb) started losing power unless I floored it last week. It was like a bad accelerator pump in the carb. I had to kick in the secondary to get any power. It started cutting off at idle the next day. I had to plug up the large vacuum hose that connects under the air filter housing to make it idle. Now I am getting about 9 mpg and it has no power unless I floor it. What is the deal?

 

blown rotor?

 

I get the feeling that is not a good thing! Before this problem, every now and then it would bog down and would not get up and go unless I changed gears and released the gas and then pressed on it again. Supposedly this car has a recently installed carb within the last year. I bought it 4 months ago.

 

have you checked the basics - fuel filter, spark plugs, etc.?

 

Replaced Autolite plugs last month (before Problem) w/ NGK plugs. Since problem, R&R rotor button and dist. cap. I do notice that when I remove the gas cap (when it gets low) I have major back pressure in the tank.

 

Prior to this problem, I replaced the plugs w/ NGK's. After the problem, I replaced the rotor button and cap. When I refuel, there is backpressure in the gas tank, especially when it gets really low.

 

My guess is that you don't have the emissions control **** hooked up correctly. Your accelerator pump is probably fine, albeit with an old diaphragm unless recently rebuilt. But you describe a carburetor problem in which there's simply no way that it would deliver that much fuel. The fuel has to be being sucked out of the carb by some vacuum source.
Possible explainations for this include plugged up air bleeds (the jets directly over the arms that hold the tiny booster venturis in place [ called emulsion tubes]), or in improperly routed vacuum line. (Got me.)

There's another possible source for extra fuel, though usually you can't get the engine started with this malady; There's a solenoid directly smack in the middle of the carb body on the drivers side with a single black w/ white striped wire hangin' off, and if that's not hooked up, the carb can't vent properly, and will flood wildly. I suppose if the solenoid spring had rusted due to it being a junker carb, it might be stuck partially, allowing for you to be able to start.

The wooshing you're experiencing when opening your tank is no doubt due to the charcoal canister not being hooked up properly- however, the lines could be hooked up correctly, but plugged with condensate.
Is there white goop inside your oil filler spout?

Get a Haynes manual, and at least familiarize yourself with all of these things so it won't sound like Greek when other's try to explain what to do. It will be less frustrating for you, and I can promise you you're not going through anything that other Rx-7 restoring guys have'nt as well.

You'll be running well in no time.