I posted earlier this year....Rebuilt the cars, new plugs and fresh
gas, it was running well until last week.
At WOT it was dying and would stall. I found that when I pumped the
fuel line bulb, it would run fine. Since then I have put in the VRO
rebuild kit ( Diaphragms ) . The vacuum line seems to have proper
suction, I even bought a new OMC line to go from the tanks to the
engine. I have the problem with both tanks, so ,
I don't think it's the tanks, or the line to the engine. Really at
this point, I'm not sure where else to look! I'll be replacing all the
gas lines in the engine first. The only thing I can think of is maybe
there's something else in the fuel pump I've overlooked. After all
this, I hope I don't need a whole new VRO pump! Already spent $150 for
kit and lines!!
Any help would be great, thanks!!

On Fri, 03 Aug 2007 20:53:20 -0700, wrote:

Any help would be great, thanks!!

Heh - this is going to sound strange, but try a new hose from the tank
to the engine first.

The primer bulb on the hose may be loosing pressure.

On Sat, 04 Aug 2007 10:03:23 GMT, Short Wave Sportfishing
wrote:

On Fri, 03 Aug 2007 20:53:20 -0700, wrote:

Any help would be great, thanks!!

Heh - this is going to sound strange, but try a new hose from the tank
to the engine first.

The primer bulb on the hose may be loosing pressure.

Losing - losing pressure.

My bad.

wrote:
I posted earlier this year....Rebuilt the cars, new plugs and fresh
gas, it was running well until last week.
At WOT it was dying and would stall. I found that when I pumped the
fuel line bulb, it would run fine. Since then I have put in the VRO
rebuild kit ( Diaphragms ) . The vacuum line seems to have proper
suction, I even bought a new OMC line to go from the tanks to the
engine. I have the problem with both tanks, so ,
I don't think it's the tanks, or the line to the engine. Really at
this point, I'm not sure where else to look! I'll be replacing all the
gas lines in the engine first. The only thing I can think of is maybe
there's something else in the fuel pump I've overlooked. After all
this, I hope I don't need a whole new VRO pump! Already spent $150 for
kit and lines!!
Any help would be great, thanks!!


Make sure you put 50:1 in the fuel tank, don't rely upon the VRO even
more so if you even remotely suspect the fuel pump; or more generally in
an older engine.

You've done the fuel pump you say?? so if the problem persists but then
comes good when you squeeze the bulb check;

(1) Before you outright replace the fuel line, particularly the
connections (both ends). If it's a plug fitted line, the small "O"ring
seals leak & allow air to bleed in.

(ii) The fuel tank(s) has a one way valve in the outlet which can get
blocked &

(iii) The air vent into the fuel tank might be blocked (partially it has
a very fine anti spark gauze in it)


K

the VRO wires on this are not connected, all I've ever done was mix
50/1 myself. Today I took the pump apart again, the diaphragms were
not tightened properly, this time, by turning each side of the pump, I
tightened them right up. I think that may have been the problem!! I
hope so anyway.
I also replaced the lines from the crankcase and to the fuel filter
and pump.
I'll be testing it all tomorrow, if I stil have the problem, it has
to be the tank.

wrote:
the VRO wires on this are not connected, all I've ever done was mix
50/1 myself. Today I took the pump apart again, the diaphragms were
not tightened properly, this time, by turning each side of the pump, I
tightened them right up. I think that may have been the problem!! I
hope so anyway.
I also replaced the lines from the crankcase and to the fuel filter
and pump.
I'll be testing it all tomorrow, if I stil have the problem, it has
to be the tank.



Good luck!!!

K

K. Smith wrote:
wrote:
the VRO wires on this are not connected, all I've ever done was mix
50/1 myself. Today I took the pump apart again, the diaphragms were
not tightened properly, this time, by turning each side of the pump, I
tightened them right up. I think that may have been the problem!! I
hope so anyway.
I also replaced the lines from the crankcase and to the fuel filter
and pump.
I'll be testing it all tomorrow, if I stil have the problem, it has
to be the tank.



Good luck!!!

K


Upon re-reading, maybe you can take another look at that?? if all you've
done is disconnect the VRO alarm wires, but left the oil plumbing itself
in place??? that can also be a source of air getting into the fuel delivery.

That's the design issue with the VRO, all that separates the oil from
the fuel is an "O" ring on the plunger, so once that "O" ring leaks then
fuel can back flow into & dilute the oil, or if there is no oil there
(as might be the case with your system) then it will suck air into the fuel.

If the VRO is no longer needed make sure the oil supply line is properly
plugged so it can't deliver air instead of oil.

Apologies for the extra post:-)

K

Thanks, the oil line was plugged properly. I even changed that line
and put in a new plug. Today I tested it all out....
New lines, new diaphragms, new bulb/hose assembly. Same problem. Just
can't suck gas at anything other than at idle.
At first I had the vacuum line and gas supply lines swapped by
mistake and I noticed gas leaking from the larger diaphragm side. This
leads me to believe there must be an air leak in the fuel pump housing
itself. Both tanks have the same issue, and are clean and not very
old, so I don't think it's them. When I pump the bulb by hand, I can
do full speed.
I just hate to buy a new VRO for $350 and find out I still have this
problem. I don't use the VRO part anyway. It would be a huge help if
someone could let me know if I can just retrofit a different type of
Johnson fuel pump. All the others are so much cheaper, simpler and
probably more reliable!!
What I may try next is putting some gasket material around the parts
of my pump to see if that helps.
Could it be something in the crankcase? I can feel the suction from
the vacuum line, it's a pulsating suction, should it be constant? I
think it's normal anyway. Thanks for the help, I miss having a usable
boat and can't wait to get back out again.

On Sun, 05 Aug 2007 15:57:35 -0700, wrote:

When I pump the bulb by hand, I can
do full speed.

It still keeps coming back to that - you shouldn't have to pump the
blub at all once you've started the engine.

It doesn't seem likely that it's somewhere on the engine. It still
could be the tanks or maybe even the fitting where the hose attaches
to the tank. You might want to remove it, tape it with teflon and
reinstall it.

I know this is also going to sound stupid, but when you pump the bulb,
do you do it horizontally? As odd as it may sound, on my Johnson 25
which has a new hose/bulb assembly and I have to tilt the bulb up and
pressurize it - the pressure won't hold if I hold it horizontal.

You might also want to check the filler cap gasket and the tank vent -
the tank vent may be clogged.

Other than that, I can't add much to what has already been done and
said.

wrote:
Thanks, the oil line was plugged properly. I even changed that line
and put in a new plug. Today I tested it all out....
New lines, new diaphragms, new bulb/hose assembly. Same problem. Just
can't suck gas at anything other than at idle.
At first I had the vacuum line and gas supply lines swapped by
mistake and I noticed gas leaking from the larger diaphragm side. This
leads me to believe there must be an air leak in the fuel pump housing
itself. Both tanks have the same issue, and are clean and not very
old, so I don't think it's them. When I pump the bulb by hand, I can
do full speed.
I just hate to buy a new VRO for $350 and find out I still have this
problem. I don't use the VRO part anyway. It would be a huge help if
someone could let me know if I can just retrofit a different type of
Johnson fuel pump. All the others are so much cheaper, simpler and
probably more reliable!!
What I may try next is putting some gasket material around the parts
of my pump to see if that helps.
Could it be something in the crankcase? I can feel the suction from
the vacuum line, it's a pulsating suction, should it be constant? I
think it's normal anyway. Thanks for the help, I miss having a usable
boat and can't wait to get back out again.


Sorry Jarrod running out of stuff here.

Just on that using "gasket material" be aware things like silastic etc
dissolve in petrol & will just block the carbs.

As to using a different pump if it will physically fit when given a
vacuum pulse it will pump fuel but be very careful because at high power
if it doesn't get "enough" fuel the engine might run lean & that can
wreck it. Is there an outboard wrecking yard near you?? maybe get the
"correct" one secondhand & try it?? Even an electric fuel pump (should
be marine rated ......... but)

Maybe try pumping the bulb with the line disconnected from the tank(s) &
the line to the carbs off, that way once there's no fuel in the
line/pump system, you can block off the outlet to the carbs & should be
able to find any leaks as you keep pressure on the bulb. (air leaks out
much easier & more noticeably than fuel) while there's no fuel in it try
to apply some suction to each section (suck on the pump outlet with a
finger over the inlet & your tongue should hold pressure for a "short"
time, no crude comments needed:-)) Re-check the oil side is really
blocked off because the "O" ring on the plunger "will" leak.

If there are no leaks of air under bulb pressure & given you've replaced
the hoses etc so it's not sucking air at any of the hose connections???
You're happy it's not the non return valves or vent in the tank(S),
the diaphragm is OK? then;

are you sure the vacuum line is delivering a good clean pulse signal,
they have an inline valve to stop a backfire from damaging the plastic
pump; is that clear & not stopping the crankcase pulse??

Good luck

K