Vent valve help

The fuel vent valve on my carb is shot. It does not function properly. It does not hold vacuum. This morning like usual the car started fine. After about 3 seconds of running it stalls and i had to catch a ride to school. It would simply turn over, but not start. I came home after the car sat for 6 hours, and tried again with no luck. So i checked all the spark plug wiring connections and everything because the fuel bowl was at the half way mark on the window. I tried it one more time before i took the air lid off and check everything there and it fired up no problem. I drove around, no hesitation's, no stumbles of any sort, so the fuel pump is out of the question. So now i need to somehow cap off the valve for the mean time. I already tried capping off the valve, both the vacuum and vent line. I also capped off where the lines go to, so there is no vacuum leak. After i did that, the car would have hesitations starting after it has been driven, so i set everything back the way it was and it started up fine. So has anyone else capped off this valve? If so how did you do it? This happens every single morning now.

Bump....i really need to fix this for the time being. I am ordering the valve in a few hours.

I don't understand why this is causing so much problems, I've unhooked the valve before and the car runs fine. Just don't plug up the vents on top of the carb.

As for the gas tank vent to the charcoal cannister, try letting it breath... unhook the red line from the firewall to the charcoal cannister. See if that releives the pressure. Or hook constant vaccum to the valve on the cannister.

So do i still cap off the valve that attaches to the carb? And my problem is the valve on the carb is not closing when the engine is off, so fuel just vents out. So after a night there is no fuel in the fuel bowl. Do you think letting the gas tank vent will help my starting issue after capping the valve off? I only have a starting issue after capping the valve off. Mostly it happens 30 minutes after driving, it turns over for about 3 seconds before it fires even if i prime it.

So your problem is the vent draning fuel. you should be able to put a cap on the valve... but even then the vapor can still get out.

Are you sure you don't have a fuel leak at the accelerator pump.?

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Originally Posted by A20A1

So your problem is the vent draning fuel. you should be able to put a cap on the valve... but even then the vapor can still get out.

Are you sure you don't have a fuel leak at the accelerator pump.?

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Well the valve isn't holding vacuum. Where is the accelerator pump located? That would help because i have an extra carb.

http://i23.photobucket.com/albums/b3...irl/carb3b.jpg

Thanks for the quick reply. So how would i know if it is leaking? Where should i be looking for? Sorry i am not a carb expert and i did search with no results on my question.

not sure, might see some runs under the diaphragm along the carb and base, but if you have parts to rebuild the carb now could be a time to do it.

I have a rebuilt carb that my bro rebuilt. Only problem is that it would hesitation when you give gas from idle. It would run fine otherwise. So i am going to go check this out, and probably swap the carbs out.

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Originally Posted by russiankid

I have a rebuilt carb that my bro rebuilt. Only problem is that it would hesitation when you give gas from idle. It would run fine otherwise. So i am going to go check this out, and probably swap the carbs out.

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is the booster venturies in that carb tight... also it could have had a vaccum leak at the time.

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Originally Posted by A20A1

is the booster venturies in that carb tight... also it could have had a vaccum leak at the time.

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I checked the acell. pump and it seems to be fine, no leaks of any sort. The car runs fine, there are no problems. I capped off the valve now, i will deal with the weird starts. Only problem with capping it off is it will take 3 cranks to fire up, otherwise it runs just fine.

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Originally Posted by A20A1

is the booster venturies in that carb tight... also it could have had a vaccum leak at the time.

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The reason that carburetor wasn't running well was because I had a large vacuum leak at the vacuum tree in the back of the carb while I was tuning it. So that effectively threw off any adjustments I made. The accel pump in the carb currently on the car seems ok. I'd expect a faulty one to cause hesitation when the throttle is opened, but this one has no problem dumping gas into the throttle barrel when the throttle is opened up.

??? why are you posting for russian kid ? or you related I forget :)

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Originally Posted by A20A1

??? why are you posting for russian kid ? or you related I forget :)

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its his brother....lol

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Originally Posted by MessyHonda

its his brother....lol

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hehe, sh!t. :lol:

...why did I forget that

Ok, i am stumped. I replaced the valve with a new one. Hooked everything back up, and what do you know...same shit all over again. In the morning, fuel is gone out of the fuel bowl AGAIN. When the valve is capped off, fuel stays in the bowl and starts up just fine. So what is wrong?

Edit: On the other note, could it be the EFE screen? Maybe the fuel is not getting evaporated from the bowl, but the EFE screen is causing problems. I read that it heats up the fuel if the engine is 140F or lower in temp. In the morning it is around the 60's here. Could it be in any relation to the problem?

I checked the PVC valve on the charcoal canister, and it does not hold vacuum. I suspect it is the problem because it does send fuel vapors into the intake. So if it does not function properly, then that could possibly cause the engine to stall.

Here's a question for A20A1. I suspect that the fuel pump check valve is not working and thus the fuel in the lines drains back to the tank. Would this potentially cause a condition when the engine starts but quickly cuts off? The fuel bowl should have some fuel left in it, but I'm not sure if fuel input has a more direct way of getting to the throttle barrel. The one thing that has changed recently is that the car has been parked on an inclined drive-way nose up as opposed to being parked in a level garage for the entire duration of my ownership.

Yes, if there is enough fuel in the bowl and then no fuel from the pump it will run for a bit then stumble or die.

Only fuel already in the bowl can get to the idle circuit, that is the only place I can think of that will let fuel in or out at idle or rest... unless your a/f screw is missing. The rest of the fuel would go to the the resivor for the accel pump or stay in the float bowl till it evaporates.


With the car tilted I suppose it could drain quicker & pull the fuel away from the fuel pickup in the fuel tank.