Onan generator what to do

Well now i know what not to do in the future, but with all the rat crap stuck on the top of it years of it, wouldn't vacuum off, it was like a goo
from being there so long eww, it needed a hard cleaning, i did stay away from the rear winding.

where would be the best place to get the plugs and wires ? (southern california)

Thanks David

--
78 Royal #749
74 #136
Oversteer is when you hit the wall with the rear of the car, understeer is when you hit the wall with the front of the car. Hp is how fast you hit the
wall, and torque is how far you take the wall with you when you hit it.
 
Go to your favorite Auto parts store. Get two resistance type wires with the 90 degree ends for the plugs already installed. Install the wires and
cut them to the correct lengths on the coil ends. I like the coiled type center wires rather than OEM the carbon impregnated nylon string type.

Plugs should be available at most auto parts stores. Be sure to check and set the gaps on them as this is a very weak ignition system and large gaps
will definitely prevent it from starting. This is a wasted spark ignition and as such the plugs are wired in series. So if one plug fails you will
have no spark on both plugs. I do not remember the exact gaps but it is low and something like .016" or .018". I can go dig out the number if you
can not find it.
--
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
 
Changed the oil, jumpered 5 to 9 nothing happened, started checking voltages, and found the s wire to b1 starter wire chewed, repaired it and jumpered
5 to 9 and the fuel pump works, the generator cranks but doesn't run.

Thanks david
--
78 Royal #749
74 #136
Oversteer is when you hit the wall with the rear of the car, understeer is when you hit the wall with the front of the car. Hp is how fast you hit the
wall, and torque is how far you take the wall with you when you hit it.
 
Do this
http://gmc49ers.blogspot.com/2016/04/onan-start-relay-k1.html

> Changed the oil, jumpered 5 to 9 nothing happened, started checking
> voltages, and found the s wire to b1 starter wire chewed, repaired it and
> jumpered
> 5 to 9 and the fuel pump works, the generator cranks but doesn't run.
>
> Thanks david
> --
> 78 Royal #749
> 74 #136
> Oversteer is when you hit the wall with the rear of the car, understeer is
> when you hit the wall with the front of the car. Hp is how fast you hit the
> wall, and torque is how far you take the wall with you when you hit it.
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
--
Gene Fisher -- 74-23,77PB/ore/ca
“Give a man a fish; you have fed him for today --- give him a URL and
-------
http://bdub.net/gmcmotorhome.info/
Alternator Protection Cable
http://bdub.net/gmcmotorhome.info/APC.html
 
That all looks good gene,
https://goo.gl/photos/Ez4V5yDkF9Kjqia98

I removed the control board, was going to clean it, but i had another control board from my 74 coach's gen, so i put it in just to test and it does
the same thing, the engine cranks but doesn't run

Thanks David

--
78 Royal #749
74 #136
Oversteer is when you hit the wall with the rear of the car, understeer is when you hit the wall with the front of the car. Hp is how fast you hit the
wall, and torque is how far you take the wall with you when you hit it.
 
> That all looks good gene,
> https://goo.gl/photos/Ez4V5yDkF9Kjqia98
>
> I removed the control board, was going to clean it, but i had another control board from my 74 coach's gen, so i put it in just to test and it
> does the same thing, the engine cranks but doesn't run
>
> Thanks David
An internal combustion engine needs exactly FOUR things to run: Air/fuel mix, compression, spark, and they all have to get there at the right time.

Compression and timing are PROBABLY NOT the problem. There is no gas getting to the cylinder OR there is no spark getting to the cylinder.

The spark on these is too weak to see in daylight.

Spritz some starting fluid into the carb air inlet while the engine is spinning with the starter. If it pops or sputters, you have a fuel delivery
problem. If not, you have no spark.

Let us know after you have tried that.

If the fuel pump "tick tick tick" didn't slow down to a near stop, there is no gas getting to the carb.
--
73 23' Sequoia 4 Sale
73 23' CanyonLands Parts Unit 4 Sale
Upper Alabama
"When I grow up I am going to be a curmudgeon."
 
i did check the compression, it's at 70 both sides.

I do believe it's a no spark issue, i checked the voltage on the coil and i'm not getting any, with or without the 5-9 jump while not cranking and
while cranking

Thanks David
--
78 Royal #749
74 #136
Oversteer is when you hit the wall with the rear of the car, understeer is when you hit the wall with the front of the car. Hp is how fast you hit the
wall, and torque is how far you take the wall with you when you hit it.
 
> Changed the oil, jumpered 5 to 9 nothing happened, started checking voltages, and found the s wire to b1 starter wire chewed, repaired it and
> jumpered 5 to 9 and the fuel pump works, the generator cranks but doesn't run.
>
> Thanks david

I guess the next thing to do is to see if you are getting any gas into the carb.

HAVE A FIRE EXTINGUISHER RIGHT BY YOUR SIDE before doing this. Disconnect the gas line at the carb. Jumper 5 to 9 and you should hear the fuel pump
running. Right after that you should see gas coming out of the fuel line.

Do not run it too long and spill gas all over the place.

When you disconnect the jumper from 5 to 9 there might be a small spark on the other side of the Onan and you do not want to start a gasoline fire
from the spilled gas. If there is no gas there then we need to find out why. If there is gas there then we need to look at the carb bowl and see if
there is gas there.
--
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
 
> i did check the compression, it's at 70 both sides.
>
> I do believe it's a no spark issue, i checked the voltage on the coil and i'm not getting any, with or without the 5-9 jump while not cranking and
> while cranking
>
> Thanks David

12 VDC is supplied to the coil and the fuel pump by the same circuit. With 5-9 jumpered you should have +12 vdc at the coil. Check it with a meter
to be sure.

This is a "wasted spark" ignition and it does not act like you would expect it to. High voltage leaves the coil on one heavy wire and returns on the
other heavy wire (NOT GROUND). So to test for high voltage you would need to check between the two wires at the coil and NOT between one of the wire
and ground. Ground is simply used as a method of connecting the two spark plugs together in series. There is no connection between ground and the
high voltage secondary side of the coil.
--
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
 
the fuel is coming out, and also when i removed the screen to drain the fuel out of the carb bowl, fuel comes out, I believe it's a no spark issue as
there's no voltage at the coil

Thanks David
--
78 Royal #749
74 #136
Oversteer is when you hit the wall with the rear of the car, understeer is when you hit the wall with the front of the car. Hp is how fast you hit the
wall, and torque is how far you take the wall with you when you hit it.
 
Yeah no voltage at the coil so first I traced the wire on the driver's side of the coil which goes to some kind of contact switch and it wasn't
passing though, cleaned the contacts and now it does this must be the lop and the ground side of the circuit, and now the coil is getting ground but
still no voltage
--
78 Royal #749
74 #136
Oversteer is when you hit the wall with the rear of the car, understeer is when you hit the wall with the front of the car. Hp is how fast you hit the
wall, and torque is how far you take the wall with you when you hit it.
 
I checked once again after cleaning that lop contact and it's got 12volts when jumpered, it's now to dark to mess around with it but there's tomorrow

Thanks David

--
78 Royal #749
74 #136
Oversteer is when you hit the wall with the rear of the car, understeer is when you hit the wall with the front of the car. Hp is how fast you hit the
wall, and torque is how far you take the wall with you when you hit it.
 
The ground on the primary (low voltage) side of the coil is through the points that are mounted top center of the engine underneath a steel cover.

There is no ground on the secondary (high voltage) side of the coil.

As I stated before, the high voltage goes out one high voltage lead of the coil through one plug, to the engine. From there is travels through the
engine to the other plug and back in the other high voltage lead of the coil.

BOTH PLUGS fire at the same time as they are wired in series. You can not check for spark at one plug if the other plug disconnected. That is how a
"wasted spark" ignition works.
--
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
 
alright i get it with the spark, but i do believe that it's not getting any also the fuel line was old and cracked when i moved it, so i need to
replace it, this is going to the back burner on my list of things to do, i really wanted to see what condition the generator was in, (when i got work
on the fuel tank/lines, roof issues vents/ac/pipevents and bad cv boot, might just do a 1 ton upgrade and anything else to get it moving) so i could
decide to replace or repair, i'm leaning towards replacing, but before that i'll get someone that knows more then me to take a look at it and give
their opinion though

Thanks David
--
78 Royal #749
74 #136
Oversteer is when you hit the wall with the rear of the car, understeer is when you hit the wall with the front of the car. Hp is how fast you hit the
wall, and torque is how far you take the wall with you when you hit it.
 
Here are a few thing you can do with the spark.

Remove just one plug. Leave all wires attached to both plugs and the coil. Place the removed plug where you can see it with the frame of the plug
against the engine(ground). Jumper pin 5 and 9. Then crank the engine and look for spark across the plug. It is a very weak spark.

If there is no spark, Then unplug both spark plugs and read the resistance between both of the spark plug wires and through the coil. If should read
several thousand ohms, But NOT open.

If that was good, then with the power off (no 5 to 9 jumper), read the resistance from the minus side of the coil to ground. Slowly crank the
engine, by hand if possible, and you should see the points opening and closing on the meter (switching from high resistance to 0 ohms). If you crank
the engine with the starter, you will need an analog meter to see this transition as a digital one will not update fast enough for you to see.
Cranking the engine over by hand slowly is preferred.

If you are not seeing these transitions, then probably the points are dirty and the surfaces should be cleaned.

If you are seeing transitions, then place the engine with the points open (high resistance on the meter). Reattach all of wires but leave the one
plug out and positioned against the engine as before. Now jumper 5 to 9 again. Take a second jumper and attach it to the negative side of the coil.
Now touch the other end of the negative jumper to any ground on the engine. Every time that you remove the jumper from the engine (ground) you
should see a single spark jump across the plug. Be careful with your hands and face as you do this as it is applying spark to both cylinders without
the engine turning. If there is any fuel remaining in the cylinders the engine could jump or backfire the first time that you do this.

If you get spark at the plug, then you have proven that everything is good in the ignition system except for the points.



--
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
 
You must log in or register to reply here.
Applied GMC
Get your shine on at www.cruzingear.co

Share this page

Share this page
Top Bottom
Back