1967 Johnson 6hp seahorse run about 1 min and die

[karoteleo]

I am new to this forum.
I just bought my first outboard motor(1967 6hp johnson seahorse).
After it runs for about 1 minute, it will die.
I opened top cover and found some fuel on the edge of the gasket which located on the top of float chamber.(not sure where those fuel come from)
Then I started motor again and I found after it ran for a while, some air bubbles appeared in "fuel pump to carburetor" hose(seems coming from carburetor side). After more air came in, fuel stopped pass through hose then motor died.
I think it should have somewhere leaking in carburetor, but not sure which part.
I just want to get some ideas how can I locate the leaking before I take the whole carburetor apart.
Thanks.

 

[Crosbyman]

air bubbles suggest air leaking could be just a loose screw on the pump filter cover plate ??

​ not likely to come from the carb since the pump normally pushes ...to the carb have you noticed the direction of flow on the bubbles ?

​air could be sucked in from a bad side connector ,a bad hose ? (pump the bulb to see if you have fuel pissing out somewhere along the connections up to the carb ) as the carb fills up the bulb should harden up with no fuel leaking

​the pump itself could be defective (bad check valve bad diaphragm )

​btw keep that air vent open on the fuel tank

servicing the carb is not a big job lots of utubes around to learn from. if you are a new motor owner you need to acquire these skills

http://www.leeroysramblings.com/OMC_6hp.htm

 

[karoteleo]

the bubbles flow from carb side to pump, that's why I suspect leaking is from carb
But when I prime bulb I can't see any fuel leaking, and bulb will be firm after I prime couple times
the vent is opened for sure
Maybe the leaking is not that bad, so there is no fuel pissed out
I will double check both sides of hose clamps to make sure the leaking is not from there
If it doesn't work, I have no choice to take carb apart.
like you said, I need to learn these skills anyway.
Thanks, Crosbyman

 

[Joe Reeves]

Before looking into the air/fuel leak thing, try this....................

While running, pump the fuel primer bulb, acting as a manual fuel pump. Does this cause the engine to stay running?

Let us know what you find.

 

[oldboat1]

Check for overheating (top of head shouldn't be too hot to touch). Operate in a big barrel with water about half way up the leg -- or in the lake.

Along with the fuel pump test suggested above, raise the tank on a stool or workmate. If the pump is weak, it may struggle to draw from the bottom of a stand to the powerhead (it's a small pump). Make sure the tank vent is open.

 

[Crosbyman]

if those bubbles flow backwards ... to the pump...... I suspect the pump would be defective since it is suppose to flow outwards only. it may indicate a defective diaphragm if " vacum" is reaching the fuel side internals of the pump.

one test you can try is remove the pump and just blow air into the fuel outlet port back to the pump. if air actually flows back in the pump it is not "check valving" correctly . air should only flow from fuel inlet to fuel outlet outlet

http://www.leeroysramblings.com/Rebuilding_fuelpump.htm

 

[karoteleo]

Before looking into the air/fuel leak thing, try this....................

While running, pump the fuel primer bulb, acting as a manual fuel pump. Does this cause the engine to stay running?

Let us know what you find.

I tried. It worked.
It stay running as long as I keep pumping bulb.
Is that mean something wrong with the pump not leaking?

 

[karoteleo]

if those bubbles flow backwards ... to the pump...... I suspect the pump would be defective since it is suppose to flow outwards only. it may indicate a defective diaphragm if " vacum" is reaching the fuel side internals of the pump.

one test you can try is remove the pump and just blow air into the fuel outlet port back to the pump. if air actually flows back in the pump it is not "check valving" correctly . air should only flow from fuel inlet to fuel outlet outlet

http://www.leeroysramblings.com/Rebuilding_fuelpump.htm

Is that mean there suppose to has some air in carb, because pump is defective make those air flow backwards to the hose?
That's mean the pump should always keep pumping fuel to carb no matter there is any air in the hose, am I right?
I will read the link you sent and do the test.
Thanks

 

[Joe Reeves]

I tried. It worked.
It stay running as long as I keep pumping bulb.
Is that mean something wrong with the pump not leaking?

That indicates that the fuel pump is faulty. Replace it.

 

[Crosbyman]

pump works one way only never backwards... there is always air in the carb body above the fuel level (normal) what is not normal is the pump sucking backwards

as indicated by JR ... replace it $$$$ or... rebuild it with a kit ... less $$$

if you rebuild get the kit and read the instructions 2-3 times BEFORE working on the pump. work on a clean surface carefull with small parts flying off (springs and nylon caps ) ALWAYS finish with a blow test

good little motors

 

[karoteleo]

Thank you for all your helps guys.
I searched the parts. Seems fuel pump will cost 100 bucks. rebuild kit is much more cheaper.
I will try to rebuild it first.
By the way, my motor needs to pull many times to start. Is this pump issue cause that as well?

 

[oldboat1]

I just bought a pump for about $36 -- Chinese pump. So far, seems to work fine.

 

[Crosbyman]

interesting option probably easier to swap...those square pump kits don't like fat fingers

https://www.amazon.com/dp/B01N3JSZO7?psc=1

 

[oldboat1]

^^agree. Also have the fat finger syndrome....

 

[karoteleo]

interesting option probably easier to swap...those square pump kits don't like fat fingers

https://www.amazon.com/dp/B01N3JSZO7?psc=1

But my part number is 0388685, I am not sure would this one fit my motor?
or most of motors are compatible.
according to these small tiny parts, all of our fingers are fat fingers(not include those beauties)
beauties shouldn't do this job anyway^_^

 

[oldboat1]

may stick out further from the block than yours (need that on my 9.9, or at least fits best). You may be able to use it or a similar one, though -- think about hose configuration and fit under your cover/hood. Look for Sierra pumps here at iBoats -- probably in the $40s (?).

 

[Crosbyman]

the kit is tricky but the worst is fitting small springs and mushroom caps.

I crazy glue the springs on their mating nipples and I glue the caps on the springs with a drop of crazy glue ..then stack the rest on top

 

[bspeth]

tune up your ignition while you are getting parts,fuel and spark will cure the many pulls to start.