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Hi Hank,I have a problem I hope you can help me with ....my…

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Hi Hank, I have a problem...
Hi Hank,
I have a problem I hope you can help me with ....
my onan 2.8 runs fine for 5 min.s then dies...I have gas from the tank, and I took the gas line off of the carb and I have gas there...but...after the last time I ran it and motor died I immediatly took the line off of the carb and ...no gas came out when I turned the motor over..
so, I have gas coming out of feed line for 5 min's then it stops..( how weird is that, almost exactly 5 min's each time)
my start/stop switch inside coach and at gen. does not turn off unit , it starts it, but I have to pop off the plug wire to kill the motor ( in case thats related )
I did have a rodent problem before all this started, found a nest around the exhaust area so I wondered if that might be a cause for my problems, but to have gas pumped, then not is confusing me...
I wonder if siphoning gen. gas line is one thing, but when fuel pump is actully sucking the gas it is getting air in system...?
thanks..
Mike
Submitted: 8 years ago.Category: Small Engine
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Answered in 1 hour by:
6/28/2010
Technician: Hank F., Technician replied 8 years ago
Hank F.
Hank F., Technician
Category: Small Engine
Satisfied Customers: 15,977
Experience: Certified on Onan and Generac generators
Verified

I'll certainly do my best.

Sorry about taking so long to reply. My daughter had called and her car was broke down. I had to go rescue her.

 

The tests you have done with the fuel pump almost conclusively point to a bad pump. It is very common for them to run for a set amount of time and then overheat. Then they need to sit and cool down for a while before restarting.

There is one more test to be absolutely sure, though.

Remove the fuel line from the filter at the inlet to the pump.

Install a length of gas line to the filter and run the other end to a gas can.

Retest the pump by starting the set and letting it run until it quits. Then recheck for fuel to the carb.

If no fuel, it is definitely the pump.

If there is fuel, you may have a bad fuel line between the genset and fuel tank.

 

The no stop issue is not going to be related, but we need to fix it.

There are 3 wires at the remote switch that we need to be concerned about.

One is a ground wire, it attaches to the center terminal of the switch.

One is a start wire, it attaches to one end terminal of the switch.

The other is the stop wire, it attaches to the other end terminal of the switch.

 

Remove the access panel to the genset.

All the way to the left side, you will see a gray or black 8-pin plug going out through the oval hole in the left side of the set. This is your remote connector. Disconnect it and inspect he pins in both sides of the plug. Make sure they are not damaged or corroded.

On the side of the plug still attached to the genset, find the wires marked A, B, and C. Use a jumper wire to jump from A to C. This should make the set start (these are ground wires, so no electricity is flowing for you to get shocked).

Now jump from A to B. This should stop the set.

If this checks out, the board is good.

Now find out which remote wires correspond to those pins. Sometimes they are color coded, and sometimes they are white and marked A, B, C,.....

Reconnect this plug.

Remove the remote start switch panel.

Find the corresponding wires on the switch (the wire from the 'A' terminal will go to the center pin of the switch).

Use a jumper wire to redo the test here.

If the set still will not stop, the 'B' wire is broken between the switch and the genset.

If it will stop, the switch itself is most likely bad.

 

Let me know what you find.

 

Hank F.
Hank F., Technician
Category: Small Engine
Satisfied Customers: 15,977
Experience: Certified on Onan and Generac generators
Verified
Hank F. and 87 other Small Engine Specialists are ready to help you
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Customer reply replied 8 years ago

Hank,

 

thanks for the detailed answer..!

its dark here on the west coast of Fl. now, and it will be a few days before I can tackle this problem again.

I may need direction on replacing the fuel pump if indeed it is bad, I read from another post of yours that it is possible to do that without removing Gen..?

( checks in the mail , so to speak )

 

Mike

Customer reply replied 8 years ago

hi,

 

I am not sure I understand this part...

 

"Remove the fuel line from the filter at the inlet to the pump.

Install a length of gas line to the filter and run the other end to a gas can.

Retest the pump by starting the set and letting it run until it quits. Then recheck for fuel to the carb.

If no fuel, it is definitely the pump."

 

I did take the gas line off before from carb, started engine and it pumped fuel....

then as I said in my post I connected the line to carb and ran motor till it died and pulled line off and retested and no gas came out. there was no gas in carb either...

my next test was going to be putting a fuel line into a gas can and pull gas from it when I ran the motor to see if it was the gas line sucking air from van or the pump being bad.

 

M.

Technician: Hank F., Technician replied 8 years ago

My bad about the filter - I was thinking about the KY set, not the KV.

There are 2 fuel lines you need to be concerned about.

The first is the one from the tank to the pump.

It attaches to the pump at the top of the set, in the rear left corner.

The second line is the one from the pump to the carb. You can only see the end of this one that is attached to the carb. The other end of it as attached to the outlet of the pump, which is actually located inside the genset, on the left side, all the way to the back.

You can not run a line directly from a gas can to the carb - it will not draw the fuel in. It has to run through the pump.

On this set, to replace the pump, the cover will have to come off. This most often means having to remove the set.

It is the KY sets that you can replace the pump without pulling the set.

I will still be available if you run into anything.

Just let me know.

 

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Customer reply replied 8 years ago

Ahhhhh....

 

no, I wasn't going to go directly to the carb with the external gas can, I was going from gas can to fuel pump...to see if it would pull more than 5 min's ...that would answer the question of if the van gas line was corrupted in some way ( sucking air possibly )

or if the pump was definitly bad.

I was afrad you were going to tell me I had to remove Gen to change out fuel pump...

but as hurricane season is here I have no choice but to do this as soon as possible..

 

thanks,

M.

Technician: Hank F., Technician replied 8 years ago

If you will be able to remove the top cover without removing the set, you will be much time and trouble ahead. If the fuel pump tests bad.

 

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Customer reply replied 8 years ago

no, it has to come out of a cubby hole ... been there done that , know what in store for me...but I do have one of those small hydralic work tables to slide it out on, works great.

I am sure its the pump, but that last test of the system will decide.

by the way, the info on the wiring, is that the same for KY/KV...?

thanks,

M.

Technician: Hank F., Technician replied 8 years ago

Yes, the remote wiring is the same.

The Onan supplied wiring is all white with the letters on it, but a lot of coach makers opt to not use it.

They will use their own wiring between the set and the remote panel. There is supposed to be a standard color code, but most makers do not follow it. This is why you need to determine which wires go to which pin in the plug. Sorry, but I can't help you do that.

The hydraulic table is great, isn't it?

 

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Customer reply replied 8 years ago

Hank,

 

I tested the fuel pump...its not working at all, the only thing that makes this gen run 5min.s is the fuel the choke pulls in ....

so with the stop switch not working and the pump not working I am going back to thinking that " maybe " my rodent friend chewed a couple of wires in the back and " maybe " I will get lucky and just have to fix that..

thats the upside...the downside is , I still have to pull the gen from the cubby hole an d we both know how much fun that is. ( not.! )

it will be a couple of days before I can get the time to pull it out, I will let you know what I find...I am sure by now your dieing to know ..!! ( not ..! ) ha...

 

M.

Technician: Hank F., Technician replied 8 years ago

Please do let me know. I like to know that things work out in the end.

If you run into anything else while you are in there, do not hesitate to let me know.

And also, since you have to pull it, it would be a very good idea to test it out before reinstalling it. It may save you a lot of time and trouble.

 



Edited by Hank F. on 6/29/2010 at 3:54 AM EST
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Customer reply replied 8 years ago

Hank,

 

I have the genny out, cover off.....

I tested the fuel pump ( off a battery ) and it seems to want to run , I didn't let it run long because I wasn't sure if it would damage the unit running " dry " ....( ????? )

yes, the rodent ( from now on called the $%%^^ rat ) had a field day in there...chewed one wire completly off ( and most the insulation in unit for nest material ), its white ( of course ) and says P1-7 ( GND)

it of course was found the last place I looked, behind the start/stop cover on unit.

I have to assume this is why the switch won't turn unit off, but, might this also be why fuel pump wasn't working...???????? please say yes, that the one wire plays with both things ....as it is I will have to use my Houdini skills to fix it...the $#$% rat chewed it at a most inconvenient spot.

Thanks,

 

M.

 

Technician: Hank F., Technician replied 8 years ago

The P1-7 is the actual ground for the controller.

If it was bad, it could very well be all that was wrong with the pump.

 

But I would highly suggest testing the pump before you put the cover back on and reinstall the set.

 

Since you have the cover off, this will be very easy to do.

Just connect a piece of hose to the inlet and drop it into a gas can.

Run the outlet back to the gas can. It may mean splicing on a piece of fuel line, or simply installing a longer one to the outlet.

Connect the pump back to the battery and let it run for 15-20 minutes. If it will last that long, it will most likely be good.

I would not run it dry for very long.

"$%%^^ rat" can sure do a lot of damage, can't they?

I actually worked on one set that had been eaten up by a raccoon! I know this, because it left 'behind evidence' behind.

 

Let me know how it turns out.

 

Hank F.
Hank F., Technician
Category: Small Engine
Satisfied Customers: 15,977
Experience: Certified on Onan and Generac generators
Verified
Hank F. and 87 other Small Engine Specialists are ready to help you
Ask your own question now
Customer reply replied 8 years ago

Hank,

I was just charged another 17.00 and would really like to know if that chewed wire is the problem for both the fuel pump as well as stop switch...

I can't find a wireing diagram on line, do you have access to one..? this would save me a lot of time to know.

my plan was to test the fuel pump with fluid, but the wire at this point is more important.

M.

Technician: Hank F., Technician replied 8 years ago

We are required by Just Answer to post all answers, as some customers wish to accept more then once.

You are not required to accept them all - only one.

Every time you click 'Accept', you will be charged.

If this was unintentional, you can send an email to [email protected] and request a refund. Please be sure to include a link to this question.

 

As far as the wire - yes, it will cause the pump to quit.

But it still could be a bad pump, which is why you need to repair the wire and then test the pump, before putting the cover back on.

Click here to download a schematic.

 

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Customer reply replied 8 years ago

thanks Hank, that will help a bunch...oh, and don't mind paying, your time is worth it...!

I'll let you know how it turns out...

M.

Technician: Hank F., Technician replied 8 years ago

Please do.

And you know I am available if you run into anything else.

 

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Customer reply replied 8 years ago

Hank,

 

I fixed the wiring and tested the fuel pump ( direct to a battery)....it works fine, pumps good...( 10 min's)

I was wondering, if I unhook the starter could I test the circuit ( fuel pump ) by hitting the start button..? Like to know that works before actually buttoning it up and testing everything..even if the pump just sputters I will know that the wires I fixed were the problem.

 

also, the $%#% rat chewed up the insulation between the motor and muffler....I drove all over this town looking for more hi temp insulation and nothing...

think it would be ok without it..?

only insulation I could find was fire resistant ( foam core, silver backing )

 

M.

Customer reply replied 8 years ago

Hank my concern is that circuit board, have 0 experiance with them so not sure if disconnecting the starter and hitting the start button would hurt it...

probably not, but cheaper to ask and see if you have tried that...

 

M.

 

Technician: Hank F., Technician replied 8 years ago

You can disconnect anything you want and it will not harm the board.

The only things that will harm the board are feeding it too much voltage (24V instead of 12V), the wrong type of voltage (AC voltage on a DC circuit or vice-versa), or shorting out an output.

 

The insulation is necessary - it will prevent the heat from the muffler from overheating the engine.

The fire resistant insulation should work, if it is all that is available.

The insulation is not availabel through Onan.

 

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Customer reply replied 8 years ago

Hank,

 

thanks for the circuit board info...

I anticipated your response to the insulation and have been scouring pages and pages of Google images to try to find a photo of a 2.8 with the cover off so I could see the placement of insulation to repair mine. unfortunatly I haven't found one and since mine was made into a %$%^ rat nest I have no way of knowing...

unless of course you have one in your bag of tricks..!

 

thanks,

M.

Customer reply replied 8 years ago

Hank,

 

ran 9 min's and died, stop button still doesn't work....any suggestions..?

 

M.

Technician: Hank F., Technician replied 8 years ago

The insulation is a pre-molded, 2-piece design.

There is a lower half and an upper half.

The intention is to create an enclosed area around the muffler so the heat from the muffler is exhausted down through the vent, and is kept from getting to the engine and plastic cover.

Click here to see an illustration.

 

If the stop switch on the control panel does not work, it is either a bad switch or bad control board. The switch is part of the control board, so either way it will need to be replaced.

Click here for instructions on testing.

 

As far as running 9 minutes, we need to determine whether we are losing spark of fuel

Start the set and let it run until it quits.

Immediately check for spark

If spark is present, remove the fuel line from the carb and test the pump.

For 9 minutes, I would suspect the fuel pump.

Ignition will typically not run for more than 5 minutes before shutting down.

 



Edited by Hank F. on 7/3/2010 at 5:11 PM EST
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Customer reply replied 8 years ago

Hank,

 

After testig fuel pump direct to battery then it not working conected to unit I suspected it was the circuit board and I was right....

replaced that and it runs, stops etc....

thanks for your help..

 

M.

Technician: Hank F., Technician replied 8 years ago

No problem,

Glad it's fixed.

 

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