1998 Evenrude 90 hp 4V fuel pump

[jwood99]

I recently got her to fire after a new power pack but it bogs down and dies after 20 seconds.

She will continue to run for a minute or two if I squeeze the primer bulb every ten seconds but will eventually die

Just added a new: ignition switch, electric choke solenoid, fuel pump, one coil, and a power pack.

I removed the fuel check valve and the screen is clear & she spurts fuel through the fuel pump if i squeeze the fuel prime bulb, but will not discharge any fuel after i start the motor and disconnect the fuel pump discharge hose (i think it should ??)............and the pump is NEW

Advice please.

Additionally dose anyone know if my motor has a float bowl, i do not see one... and how do non-motorized pumps move liquids?

 

[flyingscott]

Need a model# and does it have VRO. But here is a general explanation of the pump.
​​The pump works off of the crankcase pulses. As the piston moves back and forth it makes the diaphragm in the fuel pump move back and forth. On one pulse the pump draws fuel in from the fuel tank on the next it pushes the fuel out to the carbs.

​Each carb has it's own float

 

[jwood99]

very helpful response!

I'll have to get model number tomorrow...

so if it were not bottled to the motor it would not pump?

also, does anyone know the fuel pump bolt diameter and thread count?

 

[flyingscott]

Is the vro pump still on there or was it changed. Take a pic of the pump you have there are 3 pumps you can put on that motor that work one has 3 ports and one has 2 and one is the VRO. If the VRO has been removed then I believe yours should be a 2 port that bolts to the block like the 88 hp motor. I believe the screws are 10-24. I could be wrong there.

 

[jwood99]

10-24 is what i found on line... but wanted verification

it has two ports, two bolts

I will upload photos tomorrow morning

 

[flyingscott]

Still need the model# 2 different 90s made that year. Unless you know if it's a crossflow or loop charged motor. Loop charged motors usually have louvres in the back top of the hood. I don't believe your pump works on the loopcharged motor.

 

[jwood99]

The pump started spurting fuel once bolted 10-24

after adjusting the idle she purred like a kitten

heading to the lake Saturday!!!!!!!!!!!!