I was about to start up my newly-put-together SBC and fuel started shooting out of the front fuel bowl vent when the fuel pump came on.
What the!
Any ideas? It worked before I took the carb off without a problem like this...
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I was about to start up my newly-put-together SBC and fuel started shooting out of the front fuel bowl vent when the fuel pump came on.
What the!
Any ideas? It worked before I took the carb off without a problem like this...
The only thing different this time is that I hooked up the electric choke. Could I have the pos and neg reversed? Or a bad choke?
I guess I should try it without the choke plugged in...
Sounds like your fuel float is stuck or too much fuel pressure?? Just a guess.
Don
What type carb??? Probably float.
Take the wooden handle of a hammer and lightly rap on the front bowl of the carb to see if it will unseat the float, assuming that is what you have.
In shipping sometimes they get stuck. We always had to do that to outboard motors we sold because the floats always stuck on brand new, out of the box motors.
Don
It's a Holly 600. I'll try the hammer thing since it got moved around a couple of times before I got it back on. I'll report back in a few minutes...Quote:
Originally Posted by Itoldyouso
If not, how do I check for the other potential problems?
It's a well-used Holly 600, too. It looks like it has been around the block a few times!
Whar happens in a used carb is that gas left in there turns to varnish, and it gums up the inside. Your float and needle valve are probably stuck, and sometimes the only fix is to soak the carb and rebuild it.
Don
Whar happens in a used carb is that gas left in there turns to varnish, and it gums up the inside. Your float and needle valve are probably stuck, and sometimes the only fix is to soak the carb and rebuild it.
I'm not a Holley guy, but don't they have float adjusting screws on each bowl??
Don
I don't know fi the floats have adjustment screws. I'll have to look into it. I wonder if I should just start with another carb? I guess I can always just take the Edelbrock 650 off my other V8 an run it on this one for a while.Quote:
Originally Posted by Itoldyouso
Good move. Keep a fire extinquisher handy during all this changing around.:3dSMILE:
Don
It's sitting in the passenger seat!!Quote:
Originally Posted by Itoldyouso
That's a long way to run for it if you have an engine flare-up.
It's not so far since the engine is in the rear! ;)
The adjusting screw is on top of the bowl, it has a jam nut under it. Losen the nut and turn the screw to adjust the height. There is a site plug in the side, take it out and adjust until fuel just dribbles out of there.
I would suggest taking the bowl off first and cleaning it out.
Well, I went out and messed witht the carb a little more. This time, after loosening and tightening the bowl in hopes of shaking loose the float, something changed. Fuel no longer came out of the vent, but it still ran down into the carb when the fuel pump came on.
I didn't try to start it. I wanted to ask you guys what you thought first.
Since I have a bit of a fever, switching on the Edelbrock from my other ride will have to wait a day or two.
Thanks again for all the great advice, everyone. It sounds like I need to rebuild this bad boy. I don't know squat about the internals of a carb, but I am here to learn!
before you start it CHECK YOUR OIL!!! IF YOU SMELL GAS IN THE OIL CHANGE IT BEFORE YOU START MOTOR. YOU CAN WIPE OUT CAM BEARINGS VERY EASY BECAUSE THE FUEL NO ONLY DILUTES THE OIL & DECREASES LUBRICATION ABILITY BUT WILL WASH OUT ASSEMBLY / CAM LUBE REAL QUICK & YOU CAN SCREW UP NEW MOTOR BIG TIME. 31 5w
I would also take all the plugs out of the engine and spin it over to pump out an excess gas out of the cylinders.
Make sure you disconnect the coil wire from the distributor.
It sounds like a possible sticking float, or sinking. The needles might not be in the seats properly. They might have some pieces of dirt or something on them keeping them from closing.
I had a really old and troublesome 750 and one way I would dislodge a stuck float would be to open up the sight plug and lightly jiggle it with a small screwdriver. Be very careful doing this on a hot engine with the bowls overfull. Boiling gas can be dangerous.
Something else that hasn't been mentioned is your fuel pressure. You might just be blowing the needles off of their seats with excessive pressure.
I assume that the fuel that dripped into the intake might have found its way into a few of the cylinders?Quote:
Originally Posted by erik erikson
Also, on the fuel in the oil thing: Everything back there smells like gas right now, so I don't know if I could detect it in the oil specifically. I just put new oil in before the intake went on and planned to replace it after the first startup because of the coolant that got in the system before I tore it down. I guess I might as well change it now...
Thanks for the advice. The fuel pressure is right at 6lbs, and I have been told that is right.Quote:
Originally Posted by pelligrini
Is the sight plug covered with a screw? I need to learn more about carbs, that's for sure. Tapping it with a hammer didn't seem to move the float (if that is the problem), so I will just take it all off and put my Edelbrock 650 on while it is torn down and rebuilt.
What's a rebuild kit cost these days?
This motor has been run for a total of 10 minutes, so is cam lube still an issue?Quote:
Originally Posted by 31 5w
I'll check it, though. Thanks!
Yea, the plugs are on the sides and they look like a flat screw.Quote:
Originally Posted by Saxman
You might just have the levels set up too high. See Poncho's earlier post on how to adjust them.
There's a whole lot of info on Holley's tech library.
http://www.holley.com/TechService/Library.asp
Last time I got a rebuild kit for my old 4010 I think it was around $40-50.
Summit or Jegs can give you a more accurate price.