1989 force 125 fuel pump 1258x9b

[cardude59]

i have a question about my 125 force fuel pump. in the exploded diagrams it shows a "booster spring" yet when i had mine apart it did not have one. are all the fuel pumps suppose to have this spring? i just got this engine and on it's maiden voyage it started and ran good at low speed and part throttle. when i went to full throttle it would die out and not accelerate to top rpm. i squeezed the primer bulb and it got better. i think i have a fuel supply issue. also noticed a low rpm miss in the engine that went away with mid-range rpm. FYI. i have cleaned out the carbs, set the idle mixture screw to 1 turn out and adjusted to best idle. floats are set to level with housing. new fuel supply hoses. compression is 120 straight up and down. installed a tell-tail on cooling system and have a good stream of water from that and from the nostrils. any info and help on this would be greatly appreciated.

 

[Jiggz]

Yup, there should be a booster spring on the diaphragm. If you are missing this you need to install one. Another recommendation, if you don't have one yet, is to install clear fuel filter between the fuel pump outlet and the carb inlet. This is not necessarily for filtering but more for troubleshooting fuel related problems like yours.

 

[jerryjerry05]

Some of the pumps have a spring some don't.
Your motor came with the pump that had a spring.
But who knows if the pumps ever been changed??

​Both of my 88/85's didn't have a spring.
​The 125 I just rebuilt didn't.

​Built in tank??
If your vent line is plugged it can do that?
​The inline connectors go bad and cause the same problem.
Try running a straight line without the connectors?
​The squeezie can be bad right out of the box.

They started making a 150 in 89 and found the fuel pumps weren't strong enough.
​They made them stronger(spring) and used 2 pumps to feed the 150.

 

[cardude59]

thanks for the responses. I have a built in fuel tank that I replaced several years ago with a plastic tank. the vent is clear and open. there are new fuel lines to the pump and the bulb was working fine on the old 135 horse Evinrude that was on the boat . when the bulb is squeezed it shoots a good stream of fuel and it will syphon fuel through it easily. I will be adding a clear fuel filter to the system as you suggest. thanks again for the info