g2 crank case pressure

[colsen]

I rebuild my motor and now the fuel pump will not pump. I don't think i'm getting enough crank case pressure to make the pump work is there a way to check this? I have pulling the outlet tube side of the pump and it is pumping fuel but it will not push it up to the carb. What can i do to fix this? I have bought a new pump and it still does the some thing. All the lines are free of kinks as well.

 

[ftfixer]

not very familiar with yamaha but wondering if you remove the fuel supply hose at the carb. is any fuel being pumped that far? inspect your hose and connections for loose clamps or cracks. route these hoses as straight as possible without any big dips. was this happening before the rebuild?

 

[colsen]

yes I was have issues with this before i rebuild the motor, there is not fuel getting up the hose to the carb. I can put the hose down at the level of the pump and it will push it out . But it's like the pump can't push enough pressure to pump it up to the carb. i'm thinking of putting a elec. fuel pump on, what fuel perssure should i run? is there any other things that may have issues if i run a elec. fuel pump?

 

[ftfixer]

sure sounds like the pump but like you stated you were already having the problem before and have replaced the pump. couple of more things to check think that the tank may have to vent a little bit in order to have good vaccum take a look at the fuel cap on tank and maybe leave it a little bit loose and see what happens. this happened with a chain saw that i was repairing loosened cap pulled rope a couple of times and fired right up. replaced the cap and had no problems since also had this problem with a boat fuel tank.take a look at the tube inside the tank could be loose, cracked,or broken and be sure it is sealed tight where it sticks out top of tank. might not sound like anything that will help but i have learned the hard way sometimes it can be the most simple thing. do you have the clear fuel filter? just for info. it appears it is only gravity flowing and not actualy pumping.