1980 Mazda RX7 Carb Flooding

FXPROGLJR

MEMBER
1980 MAZDA RX7

Engine Mechanical problem
1980 Mazda RX7 Two Wheel Drive Manual 90000 miles

You guys helped me solve a problem with my carb - thanks so much. I cleaned it up as advised and everything seems to work fine now.

I do have another question. The carb used to flood occasionally (that was the reason I took the carb apart many years ago). If I turned the ignition on & looked into the carb, I could see fuel just pouring into the carb through the main jets. I kept checking/replacing the needle valves and floats, but never found or solved the problem. This time I tried looking for anything that would increase the fuel pressure, so I disassembled and cleaned the fuel inlet and return assembly and paid particular attention the the small hole in the part inside that assemble called the "adapter". I didn't find any dirt, but could that be the problem?

3 Replies

MHPAUTOS

MECHANIC
31,938 POSTS

Hi there,

Thank you for the donation.

If the devilry pressure is correct and the float level is correct and the needle and seat is OK, the problem will be with a check ball or faulty power valve with in the carby, often carbys need acid cleaning to remove all scale and muck, I feel that the problem is here.

Mark (mhpautos)

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Monday, May 10th, 2010 AT 3:42 AM

FXPROGLJR

MEMBER
6 POSTS

Hi. And thanks for the help. I'm not quite sure what I did. Flooding while the car was running has stopped, but has been replaced with flooding after the engine is turned off! I've been chasing this roblem for quite a while, but since it doesn't happen all the time, I'm having a problem finding the culprit. It seems that at varying times after I turn the engine off (between 5 and 25 minutes), the float bowls empty and the gas ends up in the carb throat. (After this happens, I can refill the float bowls and it does not happen again until I start the car, drive it for a while and then turn it off) Someone mentioned HEAT SOAK so I started watching. I expected to see the gas in the float bowls (there is a sight glass) boiling and the gas being pushed out the carb jets, but that's not what 's happening. I set up a video camera looking down into one of carb secondaries and was surprised to see that the gas is not coming from a jet. After I turned the engine off and you can see things start to happen at the bottom of the carb about 1:50 into the clip. Ignore the black cable at the 1 o'clock position. It's a light source I uned to light up the bottom of the carb.

I'd sure appreciate any ideas that anyone might have as to what is happening here

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Monday, February 20th, 2012 AT 10:47 PM

RIVERMIKERAT

MECHANIC
6,110 POSTS

Ok. That's weird. It looks to me like there might be a seal or gasket that's fine as long as the carb is warm and the metal is expanded, but that begins leaking once everything cools down and shrinks back.

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Tuesday, February 21st, 2012 AT 10:54 PM