Figure this one out....
I've been posting with this same problem all summer now.... My 1999 60
horse Johnson has had fuel starvation all summer. I first tried new
diaphrams in the fuel pump $75. No fix. Then a new OMC line from tank
to engine $40. No fix. Now I bought a new VRO pump $200. No fix.
What's left? What am I missing? I miss having a boat that runs without
having to pump by hand!
Where should I look next? Could it even be the carbs? They were
rebuilt this spring though. I'm hoping somehow to figure this out, the
engine is next to useless until then. Thanks for any help!! |
Aug 27
|
| following well considered thoughts to the readers of rec.boats: |
Gene
Aug 28
|
| I've bought a new bulb. When I squeeze it, it will collapse. I think I
may check the fuel filter. It was new this spring, but maybe it's got
enough of a clog that the pump can't keep up. When I pump it by hand,
the engine runs great, up to 5500 rpm or so.
I have even tried all new lines from inlet to pump, to pulse, to
filter and to carbs, but no help. I'm hoping I've narrowed it down to
the tank or the fuel filter. It's even hard for me to pump by hand,
maybe that means there is a blockage somewhere. Could it even be the
inlet fitting on the motor?
I'll be testing and troubleshooting some more tomorrow. |
Aug 28
|
| > I'll be testing and troubleshooting some more tomorrow. If the bulb is collapsing, then that's the problem. I'm not trying to be offensive here, but check to make sure the bulb's
arrow points to the engine. Second, hold the bulb's arrow UP while squeezing until it it fairly
firm and you can't squeeze anymore. Then try the engine. If you don't pressurize the bulb, the engine
will eventually run out of gas. |
Short
Aug 29
|
| I'd think you'd be able to check this by unscrewing the gas cap enough for
air to get by before replacing the tank.
Unhook the fuel line at the carbs and crank the starter. Catch any gas that
comes out. Don't allow a cloud of fumes to build before cranking the
starter.
This should let you know if the system is working to that point.
Unless something is wrong with all (4?) carbs, this shouldn't be the problem
as it'll probably run on 2 cylinders.
MMC |
MMC
Aug 28
|
| Have you tried changing the primer bulb? |
Rom
Aug 28
|
| Also, check the vacuum line from the block to the fuel pump- could be
blocked. |
Rom
Aug 28
|
| If you can get the engine to run up to its rated RPM under load (in
gear) by pumping the primer bulb, the problem is fuel-system-related
and NOT THE IGNITION. When you have an engine starved for fuel, if the obvious stuff (closed
vent, clogged filter) is not the cause, then divide and conquer. Use a
portable tank and hose KNOWN to work on another engine. If the engine
runs fine with these, then you know that the problem is in your built-
in tank and/or its associated hose, and you just saved yourself
multiple $$$ "shotgunning" every fuel-related component on the
outboard till you finally turn to the stuff on the boat which may have
been the actual cause all along. If you think your hose is bad, try it on another engine, of
approximately equal size if possible. (Of course, don't run straight
gas through a motor that requires oil/gas premix; the hose from your
VRO-equipped engine will need to be flushed with premix if you use it
on a premix motor.) The symptoms will appear on the other engine if
the hose itself is the cause. If the other engine runs fine with your
hose, then it's probable that you can move the hose way down on the
suspect list. Even though you have done some work and replaced some parts already,
there are multiple components on the boat and motor that you haven't
yet addressed. The portable tank test should still be performed. Then
get back to us. Till you do, best we can do is simply list every
component in the system and cross off the ones you've already
replaced, assuming the replacements are good (and we all know what
ASSuming leads to). %mod% |
Aug 28
|
| The vent? Can air get into the tank to displace the fuel that you burn? Dan |
Dan
Aug 27
|
| That's next I guess. I will get a new tank incase maybe it's clogged
screens or vent. I really hope that's what it is, since I have no clue
where else to look beyond all that I've done already. |
Aug 27
|
| You sure the advance is working OK? <jarrod_taylor@mac.com> wrote in message |
BruceM
Aug 28
|
| I'm sorry, but, what's the advance? Something with timing? I had
checked the crankcase puls line at one point and it had good suction.
Are there other adjustments I may need?
The strange thing is that the engine ran fine until July. It's just
struggling to get gas for some reason. |
Aug 27
|
| I'm referring to advancing the timing of the sparkplug firing.
With the motor turned off, try pretending to give it full throttle.
I'm not familiar with your motor but on everyone I've had anything to do
with, you should see the guts of the magneto UNDER the flywheel rotate. If
not, look for the connecting rod that might have dropped off.
On cars etc it is usually vacuum controlled & not linkage drect from
throttle.
Sounds like yours is OK on idle but not advancing on higher revs.
Ofcourse it might be vent blocked in cap like other comment. Try it with the
lid off the tank?
I also have seen outboards come out of the factory with high altitude jets
instead of low altitude ones causing similar symptoms as yours.
<jarrod_taylor@mac.com> wrote in message |
BruceM
Aug 28
|
