carb help

W

waltere

Senior Member
Ok guys I need some help!! Trying to learn! Getting ready to fire up my first flatmotor build. I have a pair of original 97's that I had profesionaly rebuilt. They have been setting for about a 2 years. Electric fuel pump, fuel regulator set at 3 psi, fuel presure guage says just a little over 3 psi, one carb is nice and dry but the second carb is running gas out around the top plate and i can see fuel dripping inside the pot. Where do I start. I do not want to try to start the motor until I get to the bottom of the problem.
Thanks in advance
Walter :confused:
 
Well, the problem, of course, is that the needle valve is not stopping the fuel flow when the fuel level reaches the correct height in the float bowl. That is the general problem---the specific cause will need to be determined. Either of several possibilities exist. The needle and seat are within the brass inlet fitting in the side of your float bowls. The needle can be stuck, the float can be leaking and filling with fuel, the needle engagement arm from the float can be improperly adjusted, the needle might not be coordinated with the seat, there can be dirt, crud, etc. preventing proper operation, and the needle or seat can be defective.

I would remove the air horn and fuel inlet fitting and begin an examination. Since you had the carbs "professionally rebuilt", ask the professional for his opinion.
 
Drop fuel pressure so it is 2 to 2-1/2#. A bit above 3 is too high. This may not solve the problem but is where the pressure should be.
 
Yes it unscrews, they are three pieces so hold the larger brass fitting downward while unscrewing so the needle comes out with it, the gasket will come off with the inlet fitting.
 
mission acomplished! I am not certian what I found but there was like a clear snot in the needle and seat. The intire system is new so i just do not know where it came from. 3 psi and no leaks so I think I am good to go.
Thanks
Walter
 
I will take the advise and set the pressure back to 2.5psi and see how it works. Thanks for the help! I am certian I will need more in the future.
Walter
 
Set the pressure with the engine running, if the engine is not idling the pressure readings will be falsely high due to 'pressure' creep.
 
3# was too high for my brand new 97's, lowered to 2½# and no problems since.Good luck with your flathead.
 
Ok! Now more help please. Fuel system is working and not leaking. I pulled the drain plug (fresh engine never had oil in it) to prelub the oiling system and and I had a about a quart of fuel run out the bottom of the engine. What have I damaged since this. The engine was not turned over so I would asume the gas evaporated from the cylinders. Advise would be appreciated.
Thanks
Walter
 
waltere said:
Ok! Now more help please. Fuel system is working and not leaking. I pulled the drain plug (fresh engine never had oil in it) to prelub the oiling system and and I had a about a quart of fuel run out the bottom of the engine. What have I damaged since this. The engine was not turned over so I would asume the gas evaporated from the cylinders. Advise would be appreciated.
Thanks
Walter
Click to expand...

You haven't hurt anything. It would be nice if you had a pressure tank to prelube the engine. Fill it up with oil and fire it up. Walt
 
Thanks Walt! I used a tool a budy loned me and it uses a chevy oil pump driven by an electric motor. I plumed into the oile sener and pumped about 2 quarts through the motor that way.
 
With the drain plug out did you run the fuel pump to see if you were still getting fuel into the engine?
A quart of fuel seems excessive for just one carb to have leaked past stuck needle & seat. Although it wouldn't take much fuel to look like a quart.
 
I did check and it stayed dry with the pump running. I soaked up the gas and it took the most part of a bath towl. Not an exact measurement but it seemed big when it was running out
 
waltere;840737[B said:
]I did check and it stayed dry with the pump running. [/B]I soaked up the gas and it took the most part of a bath towl. Not an exact measurement but it seemed big when it was running out
Click to expand...

Thats the important thing. No need to quatify unless you are accounting for gas missing from the tank, and you aren't. It seemed like a lot of fuel and thats why I asked.
 
I realy apreciate the help. This probably a more Hamb freindly flathead but it certianly seems that when I need nuts and bolts help the Barn is where it is at. I know about enough about a flathead to be dangerous but I do want to learn. My Brother in law (Mr. Merc.) is comeing down and going to help me fire the motor tomarrow night. It is going to be a family event. 3 states will be represented. Actualy it will take that much BS and bench talk to make it happen.
If I have more questions I will be back!!
 
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