Polaris ATV Forum banner

1 - 6 of 6 Posts

·
Registered
Joined
·
9 Posts
Discussion Starter #1
I have a 2000 sportsman 500. I can't seem to get a pulse from the carb to work the fuel pump. I can blow into the fuel pulse line and get fuel to pump out. Also did a vacuum check on the pump and it looked good. It seems like the carb is not pulsing the pump. I started it up using a squeze ball to pump fuel. I put a vacuum gage on the carb but got no reading. It's a new carb. How does the carb get it's vacuum.
 

·
Registered
Joined
·
4,629 Posts
Carbs get vacuum from the venturi effect. In these models, the venturi is augmented by the rubber diaphragm and vacuum slide. If yours is new I can't imagine that there is an issue with it, but the rubber diaphragms of older models can wear out or get small holes reducing their efficiency.

Your carb isn't what creates the pulse, it's the engine BTW.

When you pull the inlet line off of the carb and turn the key is there a steady stream of fuel?
 

·
Registered
Joined
·
9 Posts
Discussion Starter #3
Thanks for the reply. I know about the venturi effect. Can't understand why the 2 carb ports for the pump pulse end up in the fuel bowl. I have the old carb and verified.
 

·
Registered
Joined
·
4,629 Posts
I know about the venturi effect. Can't understand why the 2 carb ports for the pump pulse end up in the fuel bowl.
There is only 1 pulse line from the carb to the fuel pump :thinking:

If you know about venturi, then I must have misunderstood your first question "how does the carb get it's vacuum."
 

·
Registered
Joined
·
9 Posts
Discussion Starter #5
The pump does have 1 pulse line but carb has 2 ports that are "TEE"d into 1 line. If I disconnect the fuel supply line and crank the engine I don't get anything out. If I puff air into the pulse port on the pump I get fuel.
 

·
Registered
Joined
·
4,629 Posts
OK, I see what you're saying now.
 
1 - 6 of 6 Posts
Top