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Re: [GMCnet] Bringing Onan back to life due to impending hurricane [message #182108 is a reply to message #182086] Tue, 28 August 2012 11:16 Go to previous messageGo to previous message
USAussie is currently offline  USAussie   United States
Messages: 15912
Registered: July 2007
Location: Sydney, Australia
Karma:
Senior Member
Robin,

When I watched the video the first thing I noticed was how clean the Onan appeared to be. This suggests that has very few hours.
That could be verified by checking what the hour meter reads.

I am of the opinion that by trying to jury rig this unit and get it going ASAP could cause damage that is unnecessary. ToddS has
given you some VERY GOOD advice. I am going to continue along his lines below.

The device you called the fuel filter in the video is actually a solenoid. When energized it allows fuel to enter the bottom of the
fuel pump.

If you look carefully at the fuel pump you will see that there are three tits equally spaced around the bottom and there's a nut on
the bottom.

I suggest you:

1) remove the fuel pump and solenoid from the Onan (Ref: Parts Book 78Z page 28-51)
2) put the mounting tab of the fuel pump in a vise with the bottom facing upwards
3) remove the solenoid from the bottom fitting of the fuel pump
4) screw the fitting that is in the inlet to the solenoid into the inlet of the fuel pump
5) remove the Cover (Key 1) of the fuel pump using a wrench
6) remove the Filter (Key 4)
7) inspect filter and housing for varnish left by evaporated gasoline
8) clean the filter by spraying carb cleaner from the ID towards the OD
9) remove the Retainer (Key 5) and remove Keys 6-10
10) clean all those items with carb cleaner
11) in the center of the pump housing there is a plastic check valve; clean it with carb cleaner and make sure it moves easily
12) slide the Plunger (Key 10) back into the fuel pump and make sure is slides back and forth easily
13) reassemble the fuel pump

Move on to the carb now Ref: Parts Book 78Z page 28-74/75

1) remove the wing nut (Key 27) and remove the air cleaner
2) hold the air cleaner up to the light and look up the inside - if it is dirty blow it out with your compressor from the ID
3) remove the fuel line from the carb
4) remove the choke and throttle connections to the carb (take a photograph so you can put them back where they were)
5) remove the screw clamp (Key 23) that holds the hose (Key 26) to the carb and remove the hose
6) remove the two nuts & washers (Key 3 / 4)
7) GENTLY move the carb up and down to break the carb to manifold seal trying not to damage the gasket

Ref: Onan Operators Manual and Parts Catalog 6A73 Page 13 - Carburetor Parts Group

http://www.bdub.net/manuals/Onan/Onan6kwNH_Operator-Parts.pdf

8) gently screw in the Idle needle (Ref No. 16) on the side of the carb and count the turns carefully - write the number of turns
down. Do not screw the needle in HARD, you WILL damage the needle / seat if you do
9) remove the Idle needle and spring
10) gently screw in the Power needle (Ref No. 15) on the bottom of the carb and count the turns carefully - write the number of
turns down. Do not screw the screw in HARD, you WILL damage the needle / seat if you do.
11) remove the Power needle
12) invert the carb and remove the Bowl Retainer (Ref No. 17
13) remove the Bowl assembly
14) push the Shaft (Ref No. 8) out and remove the float and needle
15) remove the Needle Seat (Ref 19)
16) remove Nozzle (Ref 9)

You now have the carb disassembled far enough to clean everything properly. If you look at the Nozzle (Ref 9) you will see that the
hole in this part are EXTREMELY small, you may have to soak it in carb cleaner to get the varnish out.

Once you have cleaned all the parts and there is no varnish anywhere re-assemble the carb and set the Idle and Power needles to the
recorded settings. Check the float setting as per page 13 too.

Reinstall the carb and fuel pump.

Lets move on to the ignition system:

Since your Palm Beach is a 1977 I am going to assume it has the later version of the points; ref: Onan Operators Manual and Parts
Catalog 6A73 Page 12 Figure 2. Carefully open the points and inspect them. They should be clean and shiny with no pits or tits

If they are not:

1) turn the adjusting screw until the points are fully closed
2) cut some 400 grit wet or dry paper into long strips
3) open the points manually and insert one end of the strip in the points
4) slowly pull the strip through the points
5) repeat this on both sides of the points until they are clean and shiny
6) clean the points with a bit of carb or brake cleaner being careful not to spray the shaft that goes down into the engine
7) lubricate the shaft that goes down into the engine with a bit of engine oil
8) adjust the points as per page 13.

You now KNOW that the fuel pump and carb are clean and free of varnish and the points are clean and set properly. This means you
should get gas and spark!

You are correct if you jumper #5 to #9 one the board the fuel pump will run. You could leave the connection to the carb loose and
verify that before you tried to start the Onan.

Regards,
Rob M.


-----Original Message-----
From: Robin Hood

Looks like it's pin 9 to pin 5 in order to make just the fuel pump
run. Will try that. Will also spray some ether or something around the
air filter while starting to see if I'm getting spark in the
cylinders.

--
Robin

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Regards, Rob M. (USAussie) The Pedantic Mechanic Sydney, Australia '75 Avion - AUS - The Blue Streak TZE365V100428 '75 Avion - USA - Double Trouble TZE365V100426

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