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Re: Onan troubleshoot [message #368965 is a reply to message #368803]

Sat, 05 March 2022 12:06

Ken Shaffer

Messages: 89
Registered: September 2017
Location: Marion Iowa

Karma: -1

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Thanks for all the repies. I finally had a few minutes to work on my Onan today. I isolated my fuel supply by pulling out of a separate gas can. Engine still running rough and seams to be running very rich. I will do carb adjustment procedure described above. Before the next round of rain moved in I decided to poor a whole can of sea-foam in my gas can (3gal gas). The engine almost instantly smoothed out and is running like it should. I was surprised by this. I thought it wouldn’t hurt to let this run awhile but rain moved in and I shut it down, I plan on going thru carb adjust procedure next, but anyone know why it smoothed out with Seafoam? Really just curious, I realize this didn’t “fix” the problem.

Ken Shaffer Marion Iowa 73 Canyon Lands, 455, Micro-level, Alum radiator, Alcoa wheels, Lenzi hubs/bearings, Howell EFI/EBL, Rostra Cruise, Custom interior

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[GMCnet] Re: Onan troubleshoot [message #368970 is a reply to message #368965]

Sat, 05 March 2022 12:42

k2gkk

Messages: 4452
Registered: November 2009

Karma: -8

Senior Member

I get the same results on 1999 GMC 2500 truck, 2012
Ford Flex, and 2018 Kia Soul! Wondrous stuff!

D C "Mac" Macdonald
Amateur Radio K2GKK
Since 30 November '53
USAF and FAA, Retired
Member GMCMI & Classics
Oklahoma City, OK
"The Money Pit"
TZE166V101966
'76 ex-Palm Beach
k2gkk + hotmail dot com
________________________________
From: Ken Shaffer
Sent: Saturday, March 5, 2022 12:06
To: gmclist@list.gmcnet.org
Subject: [GMCnet] Re: Onan troubleshoot

Thanks for all the repies. I finally had a few minutes to work on my Onan today. I isolated my fuel supply by pulling out of a separate gas can.
Engine still running rough and seams to be running very rich. I will do carb adjustment procedure described above. Before the next round of rain
moved in I decided to poor a whole can of sea-foam in my gas can (3gal gas). The engine almost instantly smoothed out and is running like it should.
I was surprised by this. I thought it wouldn’t hurt to let this run awhile but rain moved in and I shut it down, I plan on going thru carb adjust
procedure next, but anyone know why it smoothed out with Seafoam? Really just curious, I realize this didn’t “fix” the problem.
--
Ken Shaffer
Marion Iowa
73 Canyon Lands, 455, Micro-level, Alum radiator, Alcoa wheels, Lenzi hubs/bearings, Howell EFI/EBL, Rostra Cruise, Custom interior

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Re: Onan troubleshoot [message #368973 is a reply to message #368965]

Sat, 05 March 2022 16:39

Matt Colie

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

Karma: 7

Senior Member

Ken Shaffer wrote on Sat, 05 March 2022 13:06

Thanks for all the repies. I finally had a few minutes to work on my Onan today. I isolated my fuel supply by pulling out of a separate gas can. Engine still running rough and seams to be running very rich. I will do carb adjustment procedure described above. Before the next round of rain moved in I decided to poor a whole can of sea-foam in my gas can (3gal gas). The engine almost instantly smoothed out and is running like it should. I was surprised by this. I thought it wouldn’t hurt to let this run awhile but rain moved in and I shut it down, I plan on going thru carb adjust procedure next, but anyone know why it smoothed out with Seafoam? Really just curious, I realize this didn’t “fix” the problem.

Ken,

The Seafoam may have actually fixed the problem.

Carburetors are strange things. In recent (well, my recent) years I have found out that most of what I was told about them and what was commonly accepted is just not correct. Did you ever wonder why they have all those adjustments? You would think that they could make them correct when they were manufactured....
Well, when they were in use in Detroit production, they could be pretty close, but remember that every cycle that new car had to drive off the end of the assembly line and out to the holding lot. Sometimes they didn't start, or did start but ran like (extremely poorly). Sometimes, they fired right up and said "BANG". If more people knew what a marginal operation most of this stuff was, they would be filled with wonder.

Do you wonder why Onan still recommends that you start your new Onan every month?
Some say it is to keep moisture out of the windings. Problem: They stopped using that kind of varnish before WWII.
No, the real reason is to keep the gas (Now Motorfuel) from oxidizing or losing the lighter fractions and restricting some small but essential passage in the carburetor. Since Seafoam could well have dissolved something that was a problem, that may have "fixed" it for the time being. Check the carburetor adjustments anyway.

Matt

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

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