3000 gasser with gas pouring out of the carb

MtnMike

New User
My 1972 started running really rough and I noticed gas pouring out of the carb. Since it was the original carb (Holley) I changed to a Zenith thinking the Holley was worn out.
Now the Zenith does the same thing. The tractor will start but despite moving the throttle there is no power advance just gas pouring out of the carb. I have tried to set the fast idle screw but there is no change weather I turn it all the way in or all the way out.
I can change the fuel feed to gravity and the tractor runs fine but due to the hills around here I want the gas to come from the pump and not gravity.
I have done everything I can think of to fix this but now I'm asking the forum for help.

Thanks, Mike
 
What kind of fuel pump is it? Is it the original mechanical pump mounted up on the front of the engine or is it an electric pump? If it's electric it is likely too high of a pressure. You only need around 4 psi..
 
(reply to post at 13:04:26 07/05/16)
The pump is a mechanical pump but aftermarket, perhaps it's the problem.
I hooked the carb up directly to the gas tank and the tractor runs fine.
I'm clueless.
 
Sounds like you either have a pump that puts out to much PSI for the float or the float is set wrong or has some dirt etc in the needle seat cause the float not to be able to shut off the fuel when the carb is full
 
(quoted from post at 17:24:32 07/05/16)
(reply to post at 13:04:26 07/05/16)
I had the same problem on my 3000. Changed the fuel pump 3 times till I found a good one. One of them was developing 100PSI to the carb and gas was pouring out of the carb. I even added a pressure regulator and the 100 PSI was too much for it. I hate to say this but your problem is the fuel pump. Putting another one in is a pain, but after doing it 3 or 4 times, I got real good at it. get a gauge and check the next new one before you install it, you can pump the pump with your finger or a screwdriver. anything over 4 PSI is too much.
 

With out knowing all the details I would check the fuel pressure. I have been wrenching daily for 43 years a few mo's ago I got a hold of a bad new fuel pump that did zackly like yours. To make matters worst I got a second pump that did the same. I don't know what kind of pressure it would make it pegged my tester needle it only goes to 15PSI :shock:

I called airtex they did not know other than to say the wrong spring must have been installed in it...

http://forums.yesterdaystractors.com/viewtopic.php?t=1267652&highlight=pump
 


I too think that the pump is the problem. I will check the output tomorrow but for $35 dollars I will probably just switch it out.
I will update with my progress.
 
Yes but gravity has little to no PSI so with the pump that PSI can make a difference as to float setting and or dirt
 

I'm now thinking why even involve the pump. Since the outlet for the gas tank is the same with gravity or pump if my gas level is down then going up hill would not allow gas to flow either by gravity or pump so I may just keep the gravity hookup.
 
(quoted from post at 12:31:09 07/06/16)
I'm now thinking why even involve the pump. Since the outlet for the gas tank is the same with gravity or pump if my gas level is down then going up hill would not allow gas to flow either by gravity or pump so I may just keep the gravity hookup.

The bottom of the tank is curved and the shutoff valve is at the lowest spot in the tank, so it would have to be pretty low on fuel and on a pretty steep hill for the pump to not be able to suck any fuel out of the tank. On the other hand the carb isn't much lower than the tank outlet so a moderate hill will place the carb above the tank outlet so gravity feed would have a problem well before the pump would, in terms of both the steepness of the hill and he level of the fuel.
 

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