GMCforum: GMCnet » Onan Hard Starting

Home » Public Forums » GMCnet » Onan Hard Starting (Looking for tips on getting the Onan tuned up.)

Show: Today's Messages :: Polls :: Message Navigator

Onan Hard Starting [message #276796]

Mon, 27 April 2015 06:41

jtfred

Messages: 132
Registered: January 2015
Location: Grand Marais, MN

Karma: 0

Senior Member

I picked up the new coach n Saturday. When I was doing the walk through with the seller he started the generator on the and manually manipulated the throttle. He said that it has been difficult to start. On a stop on the way home, I tried to start the Onan from the inside switch. It wouldn't start. It was flooded. Yesterday I replaced the spark plugs. I was able to start it at the outside switch, but I did have to hold the choke open to get it going. It runs well once it is started.

Today I am going adjust the mixture according to the manual. I also am planning to upgrade to a Pertronix ignition soon. Let me know if you think there are any other adjustments that I should look at doing.

Is there any adjustment that I should do to the choke?

Thanks for the help!

John
Fayetteville, GA
1978 Eleganza

John Fredrikson Grand Marais, MN 1978 Eleganza

Report message to a moderator

Re: Onan Hard Starting [message #276800 is a reply to message #276796]

Mon, 27 April 2015 07:41

Matt Colie

Messages: 8547
Registered: March 2007
Location: S.E. Michigan

Karma: 7

Senior Member

Fred,

If you have to hold the choke open then something other than the choke is wrong. If the internal carburetor parts have not been replaced with alcohol resistant parts, then the seal on the needle and seat could be bad. That is a lot like what this sounds like. I have had a similar issue and am currently cleaning and replacing old parts.

While you are messing with it, adding a primer circuit (this is in the group documentation) is a real good idea.

The Pertronix ignition on the flywheel is a really good idea. Nobody (except one poor bloke that got his first try so close it got hit by the flywheel) has ever had less than great success with the results.

Matt

jtfred wrote on Mon, 27 April 2015 07:41

I picked up the new coach n Saturday. When I was doing the walk through with the seller he started the generator on the and manually manipulated the throttle. He said that it has been difficult to start. On a stop on the way home, I tried to start the Onan from the inside switch. It wouldn't start. It was flooded. Yesterday I replaced the spark plugs. I was able to start it at the outside switch, but I did have to hold the choke open to get it going. It runs well once it is started.

Today I am going adjust the mixture according to the manual. I also am planning to upgrade to a Pertronix ignition soon. Let me know if you think there are any other adjustments that I should look at doing.

Is there any adjustment that I should do to the choke?

Thanks for the help!

John
Fayetteville, GA
1978 Eleganza

Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Near DTW - Twixt A2 and Detroit

Report message to a moderator

Re: Onan Hard Starting [message #276801 is a reply to message #276796]

Mon, 27 April 2015 07:51

Dennis S

Messages: 3046
Registered: November 2005

Karma: 2

Senior Member

jtfred wrote on Mon, 27 April 2015 06:41

I picked up the new coach n Saturday. When I was doing the walk through with the seller he started the generator on the and manually manipulated the throttle. He said that it has been difficult to start. On a stop on the way home, I tried to start the Onan from the inside switch. It wouldn't start. It was flooded. Yesterday I replaced the spark plugs. I was able to start it at the outside switch, but I did have to hold the choke open to get it going. It runs well once it is started.

Today I am going adjust the mixture according to the manual. I also am planning to upgrade to a Pertronix ignition soon. Let me know if you think there are any other adjustments that I should look at doing.

Is there any adjustment that I should do to the choke?

Thanks for the help!

John
Fayetteville, GA
1978 Eleganza

John
There is a 1/4 od 1/8 id o ring on the main jet that often needs replacing to correct similar problems.
Local hardware store should have one.

Dennis

Dennis S
73 Painted Desert 230
Memphis TN Metro

Report message to a moderator

Re: [GMCnet] Onan Hard Starting [message #276805 is a reply to message #276801]

Mon, 27 April 2015 08:58

James Hupy

Messages: 6806
Registered: May 2010

Karma: -62

Senior Member

One word of caution about manually overriding the governed speed when the
generator is under load. Whatever you have plugged into that is NOT GOING
TO BE THRILLED WITH THE FREQUENCY OR OVERVOLTAGE CREATED WHEN YOU BLIP THAT
THROTTLE. VERY $$$$$.
Jim Hupy
Salem, Oregon
78 GMC ROYALE 403
On Apr 27, 2015 5:52 AM, "Dennis Sexton" wrote:

> jtfred wrote on Mon, 27 April 2015 06:41
>> I picked up the new coach n Saturday. When I was doing the walk through
> with the seller he started the generator on the and manually manipulated
>> the throttle. He said that it has been difficult to start. On a stop on
> the way home, I tried to start the Onan from the inside switch. It wouldn't
>> start. It was flooded. Yesterday I replaced the spark plugs. I was able
> to start it at the outside switch, but I did have to hold the choke open to
>> get it going. It runs well once it is started.
>>
>> Today I am going adjust the mixture according to the manual. I also am
> planning to upgrade to a Pertronix ignition soon. Let me know if you think
>> there are any other adjustments that I should look at doing.
>>
>> Is there any adjustment that I should do to the choke?
>>
>> Thanks for the help!
>>
>> John
>> Fayetteville, GA
>> 1978 Eleganza
>
>
> John
> There is a 1/4 od 1/8 id o ring on the main jet that often needs replacing
> to correct similar problems.
> Local hardware store should have one.
>
> Dennis
>
>
> --
> Dennis S
> 73 Painted Desert 230
> Germantown, TN
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist

Report message to a moderator

Re: Onan Hard Starting [message #276823 is a reply to message #276796]

Mon, 27 April 2015 12:29

C Boyd

Messages: 2629
Registered: April 2006

Karma: 18

Senior Member

Since you sat it runs well after it starts, maybe the choke is not working and you are having to close it to start it. This would explain why the seller had to flip the choke a time or two to keep it running. Just a thought..

jtfred wrote on Mon, 27 April 2015 07:41

I picked up the new coach n Saturday. When I was doing the walk through with the seller he started the generator on the and manually manipulated the throttle. He said that it has been difficult to start. On a stop on the way home, I tried to start the Onan from the inside switch. It wouldn't start. It was flooded. Yesterday I replaced the spark plugs. I was able to start it at the outside switch, but I did have to hold the choke open to get it going. It runs well once it is started.

Today I am going adjust the mixture according to the manual. I also am planning to upgrade to a Pertronix ignition soon. Let me know if you think there are any other adjustments that I should look at doing.

Is there any adjustment that I should do to the choke?

Thanks for the help!

John
Fayetteville, GA
1978 Eleganza

C. Boyd
76 Crestmont
East Tennessee

Report message to a moderator

Re: Onan Hard Starting [message #276824 is a reply to message #276800]

Mon, 27 April 2015 12:52

jtfred

Messages: 132
Registered: January 2015
Location: Grand Marais, MN

Karma: 0

Senior Member

Matt,

I did see a receipt that the Onan carb had been rebuilt. I can't remember the date, but it was done by Southland, so I would think that Zeb would have used the correct parts. Of course I shouldn't assume anything.

I haven't yet read anything about a primer circuit. I will search it and take your advice.

Pertronix is on the list (the list is growing). I want to get it stable as is before I add something new into the mix.

Thanks Matt!

John

Matt Colie wrote on Mon, 27 April 2015 08:41

Fred,

If you have to hold the choke open then something other than the choke is wrong. If the internal carburetor parts have not been replaced with alcohol resistant parts, then the seal on the needle and seat could be bad. That is a lot like what this sounds like. I have had a similar issue and am currently cleaning and replacing old parts.

While you are messing with it, adding a primer circuit (this is in the group documentation) is a real good idea.

The Pertronix ignition on the flywheel is a really good idea. Nobody (except one poor bloke that got his first try so close it got hit by the flywheel) has ever had less than great success with the results.

Matt

jtfred wrote on Mon, 27 April 2015 07:41
I picked up the new coach n Saturday. When I was doing the walk through with the seller he started the generator on the and manually manipulated the throttle. He said that it has been difficult to start. On a stop on the way home, I tried to start the Onan from the inside switch. It wouldn't start. It was flooded. Yesterday I replaced the spark plugs. I was able to start it at the outside switch, but I did have to hold the choke open to get it going. It runs well once it is started.

Today I am going adjust the mixture according to the manual. I also am planning to upgrade to a Pertronix ignition soon. Let me know if you think there are any other adjustments that I should look at doing.

Is there any adjustment that I should do to the choke?

Thanks for the help!

John
Fayetteville, GA
1978 Eleganza

John Fredrikson Grand Marais, MN 1978 Eleganza

Report message to a moderator

Re: Onan Hard Starting [message #276825 is a reply to message #276801]

Mon, 27 April 2015 12:53

jtfred

Messages: 132
Registered: January 2015
Location: Grand Marais, MN

Karma: 0

Senior Member

Thanks Dennis, I will look into that. Do you know if that comes out with the adjustment screw or if I will have to remove the carb to get to it?

Thanks,

John

Dennis S wrote on Mon, 27 April 2015 08:51

jtfred wrote on Mon, 27 April 2015 06:41
I picked up the new coach n Saturday. When I was doing the walk through with the seller he started the generator on the and manually manipulated the throttle. He said that it has been difficult to start. On a stop on the way home, I tried to start the Onan from the inside switch. It wouldn't start. It was flooded. Yesterday I replaced the spark plugs. I was able to start it at the outside switch, but I did have to hold the choke open to get it going. It runs well once it is started.

Today I am going adjust the mixture according to the manual. I also am planning to upgrade to a Pertronix ignition soon. Let me know if you think there are any other adjustments that I should look at doing.

Is there any adjustment that I should do to the choke?

Thanks for the help!

John
Fayetteville, GA
1978 Eleganza

John
There is a 1/4 od 1/8 id o ring on the main jet that often needs replacing to correct similar problems.
Local hardware store should have one.

Dennis

John Fredrikson Grand Marais, MN 1978 Eleganza

Report message to a moderator

Re: [GMCnet] Onan Hard Starting [message #276826 is a reply to message #276805]

Mon, 27 April 2015 12:56

jtfred

Messages: 132
Registered: January 2015
Location: Grand Marais, MN

Karma: 0

Senior Member

Thanks Jim. I will keep that in mind. I haven't had anything running on it while I have been tweaking the throttle. The only things I have used on generator so far are the water heater and the roof AC.

Thanks,

John

[quote title=James Hupy wrote on Mon, 27 April 2015 09:58]One word of caution about manually overriding the governed speed when the
generator is under load. Whatever you have plugged into that is NOT GOING
TO BE THRILLED WITH THE FREQUENCY OR OVERVOLTAGE CREATED WHEN YOU BLIP THAT
THROTTLE. VERY $$$$$.
Jim Hupy
Salem, Oregon
78 GMC ROYALE 403
On Apr 27, 2015 5:52 AM, "Dennis Sexton" wrote:

John Fredrikson Grand Marais, MN 1978 Eleganza

Report message to a moderator

Re: Onan Hard Starting [message #276827 is a reply to message #276825]

Mon, 27 April 2015 13:11

Dennis S

Messages: 3046
Registered: November 2005

Karma: 2

Senior Member

jtfred wrote on Mon, 27 April 2015 12:53

Thanks Dennis, I will look into that. Do you know if that comes out with the adjustment screw or if I will have to remove the carb to get to it?

Thanks,

John

Dennis S wrote on Mon, 27 April 2015 08:51
jtfred wrote on Mon, 27 April 2015 06:41
I picked up the new coach n Saturday. When I was doing the walk through with the seller he started the generator on the and manually manipulated the throttle. He said that it has been difficult to start. On a stop on the way home, I tried to start the Onan from the inside switch. It wouldn't start. It was flooded. Yesterday I replaced the spark plugs. I was able to start it at the outside switch, but I did have to hold the choke open to get it going. It runs well once it is started.

Today I am going adjust the mixture according to the manual. I also am planning to upgrade to a Pertronix ignition soon. Let me know if you think there are any other adjustments that I should look at doing.

Is there any adjustment that I should do to the choke?

Thanks for the help!

John
Fayetteville, GA
1978 Eleganza

John
There is a 1/4 od 1/8 id o ring on the main jet that often needs replacing to correct similar problems.
Local hardware store should have one.

Dennis

John
Should come out with the screw/jet. Even if they look good sometimes they are a fault. I remember Emery saying he has replaced over 100 at rallies over the years.

Dennis

Dennis S
73 Painted Desert 230
Memphis TN Metro

Report message to a moderator

Re: Onan Hard Starting [message #276830 is a reply to message #276827]

Mon, 27 April 2015 13:32

Dennis S

Messages: 3046
Registered: November 2005

Karma: 2

Senior Member

Dennis S wrote on Mon, 27 April 2015 13:11

jtfred wrote on Mon, 27 April 2015 12:53
Thanks Dennis, I will look into that. Do you know if that comes out with the adjustment screw or if I will have to remove the carb to get to it?

Thanks,

John

Dennis S wrote on Mon, 27 April 2015 08:51
jtfred wrote on Mon, 27 April 2015 06:41
I picked up the new coach n Saturday. When I was doing the walk through with the seller he started the generator on the and manually manipulated the throttle. He said that it has been difficult to start. On a stop on the way home, I tried to start the Onan from the inside switch. It wouldn't start. It was flooded. Yesterday I replaced the spark plugs. I was able to start it at the outside switch, but I did have to hold the choke open to get it going. It runs well once it is started.

Today I am going adjust the mixture according to the manual. I also am planning to upgrade to a Pertronix ignition soon. Let me know if you think there are any other adjustments that I should look at doing.

Is there any adjustment that I should do to the choke?

Thanks for the help!

John
Fayetteville, GA
1978 Eleganza

John
There is a 1/4 od 1/8 id o ring on the main jet that often needs replacing to correct similar problems.
Local hardware store should have one.

Dennis

John
Should come out with the screw/jet. Even if they look good sometimes they are a fault. I remember Emery saying he has replaced over 100 at rallies over the years.

Dennis

John
I will add -- when you replace the o ring turn the adjustment screw/jet back in fully closed -- gently -- and then out 1 1/4 turns for the initial setting.

Dennis

Dennis S
73 Painted Desert 230
Memphis TN Metro

Report message to a moderator

Re: Onan Hard Starting [message #276831 is a reply to message #276830]

Mon, 27 April 2015 13:36

jtfred

Messages: 132
Registered: January 2015
Location: Grand Marais, MN

Karma: 0

Senior Member

Thanks again Dennis! I will try this first.

John

[/quote]

John
I will add -- when you replace the o ring turn the adjustment screw/jet back in fully closed -- gently -- and then out 1 1/4 turns for the initial setting.

Dennis
[/quote]

John Fredrikson Grand Marais, MN 1978 Eleganza

Report message to a moderator

Re: Onan Hard Starting [message #276843 is a reply to message #276825]

Mon, 27 April 2015 17:11

jtfred

Messages: 132
Registered: January 2015
Location: Grand Marais, MN

Karma: 0

Senior Member

That was it. I replaced the O ring. Backed the screw out 1 1/4 turns and it fired right off. I still need to do some fine tuning, but the flooding issue seems to be gone.

Thanks Dennis!

John

[/quote]

John
There is a 1/4 od 1/8 id o ring on the main jet that often needs replacing to correct similar problems.
Local hardware store should have one.

Dennis

[/quote]
[/quote]

John Fredrikson Grand Marais, MN 1978 Eleganza

Report message to a moderator

Re: [GMCnet] Onan Hard Starting [message #276845 is a reply to message #276805]

Mon, 27 April 2015 17:14

jtfred

Messages: 132
Registered: January 2015
Location: Grand Marais, MN

Karma: 0

Senior Member

What kind of a range should I be getting under load. It seems to run now at 120 v and 56 to 59 hertz.

Thanks,

John

[quote title=James Hupy wrote on Mon, 27 April 2015 09:58]One word of caution about manually overriding the governed speed when the
generator is under load. Whatever you have plugged into that is NOT GOING
TO BE THRILLED WITH THE FREQUENCY OR OVERVOLTAGE CREATED WHEN YOU BLIP THAT
THROTTLE. VERY $$$$$.
Jim Hupy
Salem, Oregon
78 GMC ROYALE 403
On Apr 27, 2015 5:52 AM, "Dennis Sexton" wrote:

John Fredrikson Grand Marais, MN 1978 Eleganza

Report message to a moderator

Re: [GMCnet] Onan Hard Starting [message #276849 is a reply to message #276845]

Mon, 27 April 2015 17:45

A Hamilto

Messages: 4508
Registered: April 2011

Karma: 39

Senior Member

jtfred wrote on Mon, 27 April 2015 17:14

What kind of a range should I be getting under load. It seems to run now at 120 v and 56 to 59 hertz.
Thanks,

John

As usual, the Maintenance Manual is you friend:

VOLTAGE CHART FOR CHECKING GOVERNOR REGULATION 120 VOLT 1 PHASE 2 WIRE
MAXIMUM NO-LOAD VOLTAGE 126
MINIMUM FULL-LOAD VOLTAGE 110

SPEED CHART FOR CHECKING GOVERNOR REGULATION
MAXIMUM NO-LOAD SPEED (RPM) 1890
HERTZ (CURRENT FREQUENCY) 63
MINIMUM FULL-LOAD SPEED (RPM) 1770
HERTZ 59

Report message to a moderator

Re: [GMCnet] Onan Hard Starting [message #276868 is a reply to message #276849]

Mon, 27 April 2015 22:31

Ken Burton

Messages: 10030
Registered: January 2004
Location: Hebron, Indiana

Karma: 10

Senior Member

Your voltage and speed are within a safe range. I would leave it alone for now until you get everything else the way you want it. After that you could fine tune it if you want.

The primer circuit just allows you to run the fuel pump before starting to fill the float bowl. If is a good, cheap addition but will definitely not fix your flooding problem.

If you install a Pertronix upgrade. I was one of the people that had it hit the flywheel. In my case I mounted it with bolts, nuts, and lock washers. After a few years it shook loose. The replacement is now installed with one pop rivet and one nylon locking nut backed up with a jam nut. This one is not going to shake loose again.

Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana

Report message to a moderator

Re: [GMCnet] Onan Hard Starting [message #276885 is a reply to message #276868]

Tue, 28 April 2015 05:14

jtfred

Messages: 132
Registered: January 2015
Location: Grand Marais, MN

Karma: 0

Senior Member

Ken Burton wrote on Mon, 27 April 2015 23:31

Your voltage and speed are within a safe range. I would leave it alone for now until you get everything else the way you want it. After that you could fine tune it if you want.

The primer circuit just allows you to run the fuel pump before starting to fill the float bowl. If is a good, cheap addition but will definitely not fix your flooding problem.

If you install a Pertronix upgrade. I was one of the people that had it hit the flywheel. In my case I mounted it with bolts, nuts, and lock washers. After a few years it shook loose. The replacement is now installed with one pop rivet and one nylon locking nut backed up with a jam nut. This one is not going to shake loose again.

Thanks Ken. It started OK from the inside switch and ran OK with the load. It seems to be working well enough. I will leave it for now since the list of projects is growing. Pertronix and a primer circuit are on the list for the future.

Thanks again!

John

John Fredrikson Grand Marais, MN 1978 Eleganza

Report message to a moderator

Re: Onan Hard Starting [message #276934 is a reply to message #276796]

Tue, 28 April 2015 20:39

JohnL455

Messages: 4447
Registered: October 2006
Location: Woodstock, IL

Karma: 12

Senior Member

I have no primer and mine starts within 5 seconds after 30 days sitting. After that about 2 sec crank. Stiil on points and cond.

John Lebetski
Woodstock, IL
77 Eleganza II

Report message to a moderator

Re: Onan Hard Starting [message #276986 is a reply to message #276934]

Wed, 29 April 2015 10:34

midlf

Messages: 2212
Registered: July 2007
Location: SE Wisc. (Palmyra)

Karma: 1

Senior Member

JohnL455 wrote on Tue, 28 April 2015 20:39

I have no primer and mine starts within 5 seconds after 30 days sitting. After that about 2 sec crank. Stiil on points and cond.

I think after 40 years these things devleop their own personalities. To get mine to start, when full cold, hold prime for a 5 count, crank for a five count and release, count to 5 or 10 depending on how cold out, hit starter again, don't release started at the first cough but hold in until running. This was all determined after futzing with the Onan and the choke. If all that does not work it's get out, roll it out and start it. Once it has run for a while restarting is no problem the rest of the day.

Steve Southworth
1974 Glacier TZE064V100150 (for workin on)
1975 Transmode TZE365V100394 (parts & spares)
Palmyra WI

Report message to a moderator

Previous Topic:	Looking for vertical trim pieces
Next Topic:	[GMCnet] Rear bed - slatted frame instead of board

Goto Forum:

-=] Back to Top [=-

Current Time: Mon Nov 11 16:38:37 CST 2024

Total time taken to generate the page: 0.03594 seconds