2000 90 horse johnson Upper Fuel Pump

[rokhd]

I have a 2000 90 horse johnson with excessive oil consumption and at WOT it will bogg down. I have been looking for a vacuum leak and cannot find one with a vacuum pump. I dont have an antisiphon valve or any other type of restrictions of fuel. It has a new OEM VRO pump on it. At WOT it will bogg down unless you hold in on the key. The secondary fuel pump has a weep hole in it and if you unplug the hose from the block it will not hold vacuum.Any suggestions would be appreciated.

[tashasdaddy]

i am not aware of a secondary pump on that motor. sounds like a classic case of clogged high speed jets in the carbs, if hold the key in, that means the primer and fuel pump are working. the primer injects fuel into the the intake, bypassing the CARB.

[rokhd]

The parts book calls it a pump AY vapor part #0433352 it is next to what I would call a seddlement bowl. Also it has begun to smoke and use excessive oil, that is why I was wondering if it could be a vacuum leak in this pump.

[tashasdaddy]

OK, possibly, but i would check for a fuel restriction from fuel tank to OMS pump. if there is a restriction the pump will pump more oil, than fuel. it also could be a malfunctioning OMS pump, just over oiling.

[rokhd]

Ok if this pump isnt a secondary fuel pump any ideas what its function is?

[Kamobe]

I am having a similar problem with my 2000 90 HP Johnson...but no increased oil consumption just fuel starvation at over 4000 rpm. When I squeeze the bulb it will run for a few minutes at WOT and then bog down.

??What did you find was the problem with yours?? Thanks.

[Craig-]

I am having a similar problem with my 2000 90 HP Johnson...but no increased oil consumption just fuel starvation at over 4000 rpm. When I squeeze the bulb it will run for a few minutes at WOT and then bog down.

??What did you find was the problem with yours?? Thanks.

If your fuel system from motor to tank is good, you most likely have gummed up carburetor bowls and restricted main jets. Time to clean or rebuild.

[bob johnson]

that OTHER PUMP is on fuel service bracket as well and is the vapor seperator ....

I am not 100% sure how the fuel is moved from one to the other and when the oil is mixed in..

I am thinking the fuel that goes into the vapor seperator already has the oil mixed in....

because it has TWO fuel lines leaving it.. one to each fuel rail...


if priming makes it wake up at WOT...i would worry about running lean..

but i have always thought .running lean gave you MORE power!!! but was dangerous for the motor...


it is easy to pull the high speed jet.
what i would do is get a fine white cloth and hold out spread out under the outer brass screw on the bowl, when you take that out, try and let all the gas filter onto this material.

set aside and take the high speed needle out and then try and catch the rest of the fuel that comes out in another spot on the cloth...

all the sediment collects in the bowl, even with the molded in raised areas around the needle I think debris can get in there..

if you get some debris,

dissasemble the carbs and do a thorough cleaning...

it is seems clean at least look at the high speed jet and make sure it is round and clean..inside

I made a few tools so i can pull those jets out with out lowering the lower colwings...

which is a pain.

good luck


bob