carb problems please help
 

mine is an 85 gs mostly stock today i was driving down 534 at about 80-85 when all of a suden the car starts to bog down. at first just slightly, then a half mile further and it bogged some more this went on for about 3 miles then the car slowly came to a rest.i got out and looked everything over real fast, and noticed the sight glasses where almost completly full. i pumped the gas a few times, started her up and headed home. it only takes about 3.5-4 miles then it does it again. what could this be, i havent had any real problems with the carb until now.

Both bowls or only one? If only one, the needle and seat is most likely sticking, if both, the solenoid vent is non-op.

i think its both ill check again tomorrow. i couldnt get a good look at the one near the fire wall. where is the solenoid vent at?

The solenoid vent is right behind the alternator, under the return feul line. it has a plug coming out of it

Download the carb manual.

http://www.wankel.net/~krwright/cars/rx7/manuals.html

Change fuel filter. How much fuel in tank when this happened?? Note it, fill tank, see if problem goes away till it runs down to that point. My RX did the same thing at about a 1/3 of a tank - filled up it ran great till 1/3 again, then... ;p
Problem was gunk in tank - needed to be pulled, chem dunked at rada shop, POR-15 Tank sealed (kit: $30) and reinstalled. PITA but problem solved. IF you need to do the tank pull, for Gawd sakes take R-E-A-L close not of how the fuel lines go to which connection on the tank!!
'Luck
Stu Aull
80GS
Alaska

well the problem is still there even with the full tank i replaced the fuel filter and all soft line, check valve on return line and now the sight glasses are stating at the correct level when she starts to die, fuel preasure is at 2.5 to 3 pounds while idling. i cleaned the tank out when i first got the car. im downloading the carb manual right now, but im lost as to the cause.

Your symptoms dont quite match with flooding or the bowls being too high, especially at high hiway speeds. Almost sounds like fuel starvation from restricted fuel flow. Maybe a clogged fuel filter? Just because you changed it doesnt mean it isint restricted. How does it run at lower speeds? 40-45mph over a period? When they flood you cant see the level in the sight glasses, they just look blank cause the fuel level is over them.

Here's a test that might help narrow it down a little.

Take it up to highway speed, then floor it. What happens? (I'm assuming it bogs).

Repeat the above step, but then coast for a few seconds off the gas before you floor it. Any difference? (at this point, you will either continue to bog or will have good performance).

Here's the idea behind this test, and what the results are telling you:

If the restriction is in the carb (probably crud in the jets, which I've experienced myself), then the results will be the same in both cases.

But if the restriction is in the fuel filter or pump, or anywhere upstream from the carb, then by coasting for a few seconds before you floor it you are giving the fuel system a chance to "catch up" and refill the bowls. Once those bowls are filled, then you regain your performance until they are again depleted. Make sense?

When I had clogged jets, the car felt like it went faster by giving it less gas. The more pedal you gave it, the slower it went. I chased this issue for months before I finally broke down and rebuilt the carb. The jets were clogged with a buildup of some hard substance, but I was able to clean them up and reuse them. Good luck.

Next time it does it, get out and open the tank cap. See if it 'whooshes'. If so, then the tank isn't breathing, which can be caused by condensation or emulsified oil build-up in the charcoal canister line.

if this is the problem i would have to replace the canister? or can it be cleaned?

yesterday when i drove to the gas station to fill the tank and test someone elses theory i notices this very strong woooosh im going to test drive her right now, and see if it happens again

well the tank does wooosh but not as much as last time and the problem is still there even with the cap open a bit.