Johnson 200 Fuel Pump Problem

[ky gravy]

I've been a lurker for a long time and I've always been able to find answers without bothering all you experts... now I have a problem I can't answer.

I've had fuel pump issues all summer. With my 80 gallon internal tank, I think condensation combined with questionable gas availability on the Ohio River has caused some water in my tank. I installed a fuel/wter seperator filter and problem solved - for a while. Last week, we were out and had trouble keeping the motor running. Is seemed to not be getting any fuel. We figured out that is someone kept squeezing the bulb, we could limp on back to the dock. I checked all fittings and replaced a questionable section of hose. No help with the problem.

After reading many posts here, I ordered a fuel pump rebuild kit. (I should add that the previous owner of the 1988 Johnson 200 had the oil mix side of the fuel pump disabled). Upon inspection, I fould that the diaphram for the fuel pump was ripped and I thought I would be good to go when I got everything together- nope, same problem. Upon closer inspection, I notice a little bit of seepage out of the back of the fuel filter where the oil mix part is attached to the fuel pump. Could the tiny amount of seepage be enough to diminish the vacuum action of the pump? Everything seems in place and tight and the motor starts up once you get the squeeze ball hard - it just won't stay running...

my thought on the slight leak is that the little triangular o-ring that used to seal the oil pump part of the fuel pump might be damaged or unseated and it is causing the problem... I just wanted to get some feedback before I took the whole assembly apart again. Are there any other obvious places that a leak could cause the pump to be so weak?

I appreciate any suggestions.

John in Louisville, KY

[tashasdaddy]

replace the pump.

Vro Replacement Fuel Pump Kit "no Oil"
(for Using Oil/gas Pre-mix In Fuel Tank)

#5007422 it is in the $300 range.


$100 range on larger motor you may have to use 2 of these.
BRP Part Number: 0438559
Description: FUEL PUMP AY

There is not an aftermarket pump.

[ky gravy]

Just to be sure I understand... The first part number is a replacement pump without VRO and the second part, shown in the diagram is a different pump?

[freetime99]

The # 0438559 is the way to go in my book. I just replaced the VRO on my J60-3cyl and the difference is striking on how well that simple pump delivers fuel. I had to modify the VRO bracket to accept the new pump, wasnt that hard - just took some time, but was well worth it. I spanned the open area on the VRO bracket with some roof flashing material (cut to size) and bolted the new pump to that flat surface material. My engine now starts in half the usual time and fuel delivery is no longer a problem. Now I just have to solve my intermitant overheating.

[ky gravy]

Since we were planning a trip last weekend and I decided to change out the fuel pump on Thursday, I went with the full-on VRO replacement. The thing ran great all weekend. I've had cold start problems for several years and now they are gone too.

One question. This WAS an '88 fuel pump with three wires and now (in 2009)it has an extra purple wire. Does anyone know what that powers and where I should hook it up? I know when I touched grounded metal, the alarm went off so I don't know if it is a power source for all of the alarms or just the oil - since that part of the fuel pump is not activated.... should I leave it off until I reattach the oil side of the pump? I've got about 60 gallons of pre-mix gas that I need to use up before I can go back to the oil tank/injection system....

[daselbee]

Purple wires are always "Switched 12 volts"...in that they are hot with 12v when the key is on.
You would never connect a purple wire to ground.

[ky gravy]

Thank you, it's a start.

[bkwapisz]

Can anyone tell me if there is a rule of thumb for whether or not to use 1 or 2 of the 438559 pumps? I have a 1990 GT100 motor and I have just done the "blockoff" procedure for removing the oil side of the VRO and switched to 50:1 mix. Night and day difference. I am not sure of the longevity of the fuel side and to avoid problems next boating season I am not taking chances. I'm just not sure if one 559 pump will deliver enough fuel to the motor, or if I should just go with the 5007422 setup. I just bought this boat and really can't say what it's supposed to run like when it's 100%.


By the way, does the 438559 setups hookup to the pulse feed from the crankcase to work? I'm a little unclear on this aspect.


Thanks in advance from a Newb.

Brian.

[tashasdaddy]

they used the 438599 on the older 100 hp motors. yes, the pulse line powers the pump, same as the vro pump.

[kenmyfam]

This is my testing and opinion only !!!!
For the 4 cylinder V4's up to and including 140hp then a single pump is quite sufficient. Flow test on the single pump on my motor was way more than the motor could ever need. (30 + gallons per hour)
For the V6 models 150hp and up I would recommend 2 pumps.

[bkwapisz]

Well then since I am running only a 100 that'll be my springtime project.

Thank you, Gents!


Brian.

[Dhadley]

Those old style fuel pumps don't pump enough to properly supply a V6 looper, even if you use 2. I know some folks use 1 on a V4 looper but it's not recommended. 2 of the old pumps on a V4 looper will be fine.

Be very careful when playing with fuel delivery on a V6 looper.

[kenmyfam]

Those old style fuel pumps don't pump enough to properly supply a V6 looper, even if you use 2. I know some folks use 1 on a V4 looper but it's not recommended. 2 of the old pumps on a V4 looper will be fine.

Be very careful when playing with fuel delivery on a V6 looper.

I figured mine will pump 30+ gallons per hour at cranking speed from my testing, that would be ample for a motor that will use approximately 14 gallons per hour at WOT
(1985 V4 140HP Looper)

[bkwapisz]

I figured mine will pump 30+ gallons per hour at cranking speed from my testing, that would be ample for a motor that will use approximately 14 gallons per hour at WOT
(1985 V4 140HP Looper)

Thanks for all of your investigative work here kenmyfam. I can appreciate what it takes to get that data. Also, when I change this from the VRO to the 559 fuel pump, so I need to change the bung on the crankcase too? I read some other threads about that fitting having a pulse limiter or something in it. Some threads indicate replacement with a straight fitting, other's don't mention it.

On an off note, is a 1990 GT100 Johnson a "Looper?"

I'm confused as to what's a looper and what's a crossflow.

Thanks.