any ideas? primary venturi dumps fuel

[HondaBoy]

ok, so got everything worked out on my car and now it decides to dump fuel. in the primary barrel it dumps fuel from the venturi. not just a little bit, but a waterfall effect. hasnt ever done this. i have only let the car sit for a week and today it started this. FYI, i have done the vaccum line removal mod a few years back. everything was working properly and was tuned before this. anyways, just looking for a general idea of what it might be and something i can look for. this may mean i need to rebuild it again. i was thinking an O ring may have deteriorated or something like that. anyways give me an idea if you have one. also, this is happening at idle and doent do it as much as the throttle plate is opened.

[LX-incredible]

Sounds like a float problem, if it is happening at idle.

[skycam_313]

does the venturi move? when was the last rebuild?

[shepherd79]

check the float level. and make sure the venturi doesn't move.

[A20A1]

Yup too hight a float level... or you hooked up a vacuum line into the Air jet controller port at the back of the carb by mistake.


You might have a busted O-RING on the float valve... the lower one will cause an internal leak, the upper one will cause a leak from the top out the screw.

[cygnus x-1]

Maybe the float is damaged and is now a sink? That would dump in more fuel.

C|

[HondaBoy]

i checked and set the float level, stays right in the middle of the sight glass. i was also thinking it could be the float, but was thinking it was more like a busted O ring causing some kind of leak. i guess i'm just going to have to open it up and find out. i may go up to the junk yard and get another spare carb just for now until i have time to actually rebuild one. althought rebuilding this stock carb is pretty simple and dosent take more than a few hours.

[skycam_313]

good luck on it keep us posted

[A20A1]

replace the orings... don't bother removing the entire carb... also check that the tab isn't broken and that the needle for the needle valve didn't fall out...

also O-rings can be tricky sometimes they'll leak sometimes they wont.

also check that the rear 3 vacuum ports are hooked up like they should be... and also that the top hat gasket is good.

[HondaBoy]

well i ended up getting a carb for $20. the accelerator pump arm was broken off so i got it for that much instead of $50. i have a spare carb besides that one and i will be using parts from it to rebuild the newer one so i can have a back up if neccesary. so anyways last night i was trying to make a gasket for the top hat and decided to just leave it for now. i went and got some carb cleaner spray and sprayed it in all the vacuum lines and down the carb. also turned the a/f screw all the way in then back out to where it should be and that seemed to fix the problem with the venturi dumping fuel. so actually i dunno what caused it to do that, but now its not and is running correctly. i may try and modify the spare carb some. i was thinking to smooth out the bores would be about all i can do.

[shepherd79]

smooth out bores on what? intake? don't do it, you need ruff area on your intake manifold for proper air/fuel mixture.

[HondaBoy]

well i had thought of that, but i was talking about the barrels of the carburetor. i'd have to be sure and not get anything into the open parts though. i'm probably just going to rebuild that spare carb and not do anything special to it.

[HondaBoy]

well again, the carb is dumping fuel from the primary venturi. so i had a look at the carb and found what looks to be fuel that has leaked from the base of the carb where it meets the intake manifold. now i'm thinking it may be the base gasket. looks to be, but i dunno why it would start to leak other than the gasket is crappy. so i guess i will be getting the base gasket tomorrow or make one. i'm guessing that could very possibly be the cause of my problem.

[shepherd79]

it shouldn't dumping fuel from there. there are no wholes. i am guessing you need to get a rebuild kit and do a rebuild.
you may think it is the base gasket, but in reality it could the o-ring in the middle of the carb.

[HondaBoy]

you may think it is the base gasket, but in reality it could the o-ring in the middle of the carb.

you mean the rubber one that is oddly shaped? i went and had the base gasket and the upper rubber one ordered. i'm beginning to thinking i might as well just rebuild it again. now it is dumping fuel intermitantly, not all the time. i'm thinking its related to when the manifold and carb heat up and cool off, so something like and O ring or gasket would cause that type of problem. i'll see if i cant just make the lower gasket and see if that helps. if not i'll probably buy a rebuild kit. oh also noticed that it will start dumping fuel if i have been hard on the accelerator. after that my engine vacuum will read low, then when it stops dumping fuel the vacuum returns to a regular reading of about 20 inches.

[HondaBoy]

today i replaced the paper base gasket and the rubber gasket below the throttal plate. the rubber one looked all messed up and deteriorated. i dont think its been more than 2 years since i did the last rebuild. but then again, shitty quality rubber will do that. i still think its an internal problem. i'll be rebuilding another carb for it when i have time and just drive it the way it is for now since its running ok. i'll post up the picture of what i found later when i have some time.

[A20A1]

Hrm are you sure all the vaccum lines at the rear of the carb are connected in the right spot?

I'm not sure how foue would get into the base gasket... Just hope that the coolant isn't leaking into your manifold.

.

[HondaBoy]

no, checked for any coolant leakage, nada. decided to replace all the vacuum caps just to see if that'd help, checked the remaining vacuum lines. also capped off some things to see if the vacuum reading went up, and it didnt. had sprayed solvent around the intake manifold gasket to the head and not a leak. so its looking like the carb itself. and again its intermittant the way it starts to mess up. it'll be fine, i'll run it hard then it starts acting up. once everything gets hot the vacuum will be down at 15 inches sometimes. i'm going to try and get a rebuild kit today or something so i can start and finish it like tomorrow. as long as i drive it easy its ok for now. i still think its a problem with the carb and not the engine itself causeing the vacuum problem.

[HondaBoy]

ok, so i got a rebuild kit for the carb. anything i can smooth or open up before putting it back together? i didnt get a chance to do anything to the last one i rebuilt except the vacuum line removal. i hope the O rings in this one are better quality material than the last. i think that was the whole cause of my problem.

[A20A1]

turn the carb upside down, look through the secondary barrel with the throttle plates open. You'll see a ridge in the aluminum.