Onan fuel pump check

[Keith V]

So the ol Onan won't run, it runs on starting fluid, but not on it's own.
I have gas in the tanks
I disconnected the fuel line and ran the pump, it spurted a little fuel, so it's not completely dead.

How do I know it the pump is truely OK?
I'd know what to do on a car engine, are these things the same?
I'd put a fuel pressure gauge on it and also pump it into a can to check volume.
I'd like to verify it's not the pump as pulling this beast will NOT be fun, unlike the OE Onan, this thing it wedged in really tight, and is not on a slideout. So tight I cant get at the rear spark plug.

FWIW this is a 6500 Onan Emerald, not the stock genset

Thanks
Keith Vasilakes

 

[sgltrac]

if you have a fuel can, set it up on a stand above the genny and run a fuel
line directly to carb. If it runs that way you either have a fuel supply
problem (test by attempting to pump into a jar or such) which could be the
supply to the pump or the pump itself. If the genny runs on the gravity
tank and does not flood out or overflow then the carb should be good.

Sully
77 eleganza 2 (w 6500 emerald genny)
seattle

> So the ol Onan won't run, it runs on starting fluid, but not on it's own.
> I have gas in the tanks
> I disconnected the fuel line and ran the pump, it spurted a little fuel,
> so it's not completely dead.
>
> How do I know it the pump is truely OK?
> I'd know what to do on a car engine, are these things the same?
> I'd put a fuel pressure gauge on it and also pump it into a can to check
> volume.
> I'd like to verify it's not the pump as pulling this beast will NOT be
> fun, unlike the OE Onan, this thing it wedged in really tight, and is not
> on a slideout. So tight I cant get at the rear spark plug.
>
> FWIW this is a 6500 Onan Emerald, not the stock genset
>
> Thanks
> Keith Vasilakes
>
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> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>

 

[LQQKatJon]

???? maybe:

3. CHECK FUEL SYSTEM If the engine cranks and has spark but does not start, the problem is likely fuel related.
This can be confirmed by injecting a small amount of starting fluid into the air intake. If the engine fires and tries
to run, it is starving for fuel. Listen for the fuel pump running during cranking. Check for 12 volts at the FUEL
PUMP pin on the control board during cranking. If there is no voltage, the control board is defective. The pressure
and flow of the fuel pump (and fuel filter) can be checked by temporarily disconnecting the fuel line to the
carburetor and jumpering the FUEL PUMP pin on the control plug to battery positive. Take adequate precautions
when handling fuel. If pressure and flow are normal, reconnect fuel line. Note: If the generator has not been run
for several months, the carburetor float may be stuck closed and /or the jets and needle valves may be gummed
up by old fuel that has turned to varnish. These conditions interfere with normal fuel delivery. The automatic
choke may be stuck closed or binding so that it does not open as the choke heater warms up. On Models BGM
and NHM spec. B and later, make sure that the electronic governor goes to full throttle one second after cranking
begins. Any of these conditions will prevent the engine from starting or running smoothly and must be corrected
before proceeding.
--
Jon Roche
75 palm beach
St. Cloud, MN
http://lqqkatjon.blogspot.com/

 

[a.]

> So the ol Onan won't run, it runs on starting fluid, but not on it's own.
> I have gas in the tanks
> I disconnected the fuel line and ran the pump, it spurted a little fuel, so it's not completely dead.
>
> How do I know it the pump is truely OK?
> I'd know what to do on a car engine, are these things the same?
> I'd put a fuel pressure gauge on it and also pump it into a can to check volume.
> I'd like to verify it's not the pump as pulling this beast will NOT be fun, unlike the OE Onan, this thing it wedged in really tight, and is not
> on a slideout. So tight I cant get at the rear spark plug.
>
> FWIW this is a 6500 Onan Emerald, not the stock genset
>
> Thanks
> Keith Vasilakes
My money would be on a stuck carb float or a plugged carb port/jet.

The fuel pump pushes gas and the set runs on starting fluid means the problem is between the pump and the intake valves. The carb is the only thing
between the two.

The Onan takes maybe a gallon of fuel per hour under full load. A few tablespoons of gas per minute is a gallon. The pump is probably able to do that.

--
73 23' Sequoia 4 Sale
73 23' CanyonLands Parts Unit 4 Sale
Upper Alabama
"Highest price does not guarantee highest quality."

 

[Keith V]

If I HAD to bet it would be on the carb too, but I'm hoping it's not.

I did hotwire the pump, but I'll check again when starting.

Keith "not looking forward to pulling a 6.5KW genset" Vasilakes

----------------------------------------
k
>

>> So the ol Onan won't run, it runs on starting fluid, but not on it's own.
>> I have gas in the tanks
>> I disconnected the fuel line and ran the pump, it spurted a little fuel, so it's not completely dead.
>>
>> How do I know it the pump is truely OK?
>> I'd know what to do on a car engine, are these things the same?
>> I'd put a fuel pressure gauge on it and also pump it into a can to check volume.
>> I'd like to verify it's not the pump as pulling this beast will NOT be fun, unlike the OE Onan, this thing it wedged in really tight, and is not
>> on a slideout. So tight I cant get at the rear spark plug.
>>
>> FWIW this is a 6500 Onan Emerald, not the stock genset
>>
>> Thanks
>> Keith Vasilakes
> My money would be on a stuck carb float or a plugged carb port/jet.
>
> The fuel pump pushes gas and the set runs on starting fluid means the problem is between the pump and the intake valves. The carb is the only thing
> between the two.
>
> The Onan takes maybe a gallon of fuel per hour under full load. A few tablespoons of gas per minute is a gallon. The pump is probably able to do that.
>
> --
> 73 23' Sequoia 4 Sale
> 73 23' CanyonLands Parts Unit 4 Sale
> Upper Alabama
> "Highest price does not guarantee highest quality."
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org