Onan Hydrolocked?

P

Palmerdad

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Sep 24, 2016
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So I was giving the Onan a Sea Foam treatment through the carb and gave it a bit too much of a spurt and it bogged down and stalled and now won't
restart. I pulled the plugs and engaged the starter several times. It coughed out some liquid from one of the plug ports but once the plugs were
reinstalled it still won't start. Anyone have thoughts on what I should try next? I didn't want to try anything else until I got some different
opinions as I don't want to make it worse and I've never dealt with this before.
--
-James Palmer, Traverse City, MI
1976 Eleganza
 
And you were giving it a Sea Foam treatment because? Was it running
incorrectly when you decided to affect it by spraying something other than
motor fuel into the carb throat? I suspect that you fouled the plugs. Clean
them thoroughly with carb cleaner, re gap them to what the onan manual
calls for,or replace them and regap the new plugs to spec, reinstall, and
see what happens. If it does not run after this, check for spark to rule
out ignition related problems. If you have spark, likely that you have fuel
delivery or carb adjustment issues.
Jim Hupy
Salem, Or
78 GMC Royale 403

> So I was giving the Onan a Sea Foam treatment through the carb and gave it
> a bit too much of a spurt and it bogged down and stalled and now won't
> restart. I pulled the plugs and engaged the starter several times. It
> coughed out some liquid from one of the plug ports but once the plugs were
> reinstalled it still won't start. Anyone have thoughts on what I should
> try next? I didn't want to try anything else until I got some different
> opinions as I don't want to make it worse and I've never dealt with this
> before.
> --
> -James Palmer, Traverse City, MI
> 1976 Eleganza
>
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> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
 
Uh how much did you pour in when it quit? "It coughed out some liquid".. how much? If you hydraulic locked it you may of done damage to it. I
suspect it would take a pretty good shot of liquid to do this though. If the above suggestions don't produce results, check the compression on each
cylinder.

--johnny
--
'76 23' transmode Norris upfit, 76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.
"The road goes on forever, and the party never ends" --Robert Earl Keen
 
> So I was giving the Onan a Sea Foam treatment through the carb and gave it a bit too much of a spurt and it bogged down and stalled and now won't
> restart. I pulled the plugs and engaged the starter several times. It coughed out some liquid from one of the plug ports but once the plugs were
> reinstalled it still won't start. Anyone have thoughts on what I should try next? I didn't want to try anything else until I got some different
> opinions as I don't want to make it worse and I've never dealt with this before.

Another thing that could have happened is that the excess Sea Foam washed down the cylinder walls so that the rings are not sealing. When that
happens, so much blow-by on the intake and compression strokes that you cannot get enough fuel/air and compression into the cylinder to fire a decent
charge. If cleaning the plugs does not work and you have spark, pull the plugs and squirt engine oil into the plug holes. Turn the onan over with the
starter (plugs out). It is going to spray some excess oil out of the plug holes. That's alright. Then add a little more oil and turn it over again.
Do this several times to make sure that the oil has coated the cylinders. By doing this, you are recoating the cylinder walls with oil and giving the
rings a way of sealing. Put the plugs in and try a start. If it starts, it will smoke a lot while it is burning off the excess oil.

This has happened to me on several occasions. Especially years ago when we used to spray starter fluid into the carb to start in very cold weather.
Use of to much starter fluid would wash down the walls and the compression would drop so drastically that the engine would not start. HTH
--
Larry
78 Royale w/500 Caddy
Menomonie, WI.
 
I would never ever use that stuff in any engine. Reminds me of the elixer traveling salesmen from the wild west. Except more dangerous.
I would crank more with plugs out. Be sure that you have them gapped at .020 both the same as it is waste spark system. Next confirm oil level. Then
confirrm better than 1/2 tank fuel. You would be surprised about coincidences.
--
John Lebetski
Woodstock, IL
77 Eleganza II
 
Also you may have to hold choke open by hand to create a "clear flood" situation while cranking locally. The throttle will already be wide open by the
governor.
--
John Lebetski
Woodstock, IL
77 Eleganza II
 
> So I was giving the Onan a Sea Foam treatment through the carb and gave it a bit too much of a spurt and it bogged down and stalled and now won't
> restart. I pulled the plugs and engaged the starter several times. It coughed out some liquid from one of the plug ports but once the plugs were
> reinstalled it still won't start. Anyone have thoughts on what I should try next? I didn't want to try anything else until I got some different
> opinions as I don't want to make it worse and I've never dealt with this before.

James,

You did it wrong, but unless you upended the gallon jug into the intake, I very much doubt that you did any damage. The clearance volume of these
engines is HUGE.

If you really think that the combustion chambers need cleaning, take the covers off, then take the heads off and clean them. If the gaskets don't get
damaged (and there is no reason that they should) screw the heads back on. If you don't even own a torque wrench, just put the heads back on with a
3/8 standard length ratchet by hand. Get the screws tight, but not over tight.

Yes, as you have been told, put it back together and try cranking with the choke held open for three trys of 20~30 seconds. If it hasn't fired, let
the choke close and try again.

These old L-heads are pretty forgiving.

Matt
--
Matt & Mary Colie - '73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Still Loving OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Twixt A2 and Detroit
 
Thanks guys. I had heard a lot of good things about Sea Foam and used it in my Wheel Horse tractor with good results so I figured it would be good
for the Onan. I will try some of the things you've suggested tomorrow. One of the plugs was quite dirty when I took it out so I'm thinking of
replacing that one anyways.
--
-James Palmer, Traverse City, MI
1976 Eleganza
 
In general, I have always thought that Sea Foam was a "fuel treatment" where a small amount was added to your gasoline supply to clean out varnish and other crap.

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"--OO--[]---O-"

________________________________
From: Gmclist on behalf of James Palmer
Sent: Sunday, February 26, 2017 17:30
To: gmclist
Subject: Re: [GMCnet] Onan Hydrolocked?

Thanks guys. I had heard a lot of good things about Sea Foam and used it in my Wheel Horse tractor with good results so I figured it would be good
for the Onan. I will try some of the things you've suggested tomorrow. One of the plugs was quite dirty when I took it out so I'm thinking of
replacing that one anyways.
--
-James Palmer, Traverse City, MI
1976 Eleganza
 
After you have done everything Jim, Matt, and Larry suggested and get it running again, I suggest that you change oil very soon. That engine is a
horizontally opposed AIR COOLED engine. It is built with a large gaps in the pistons and rings to allow thermal expansion and to stay at running at
widely varying temperatures. When it is cold things (rings, pistons, etc.) contract and allow anything liquid in the cylinders to flow right past
them and into the crank case.

One other thought is while you have the plugs out, run a quick compression check. If one or both cylinders read low, squirt or two of oil into the
cylinders, crank the engine over a few tines, and recheck the compression again.

Oh, BTW, I found a good use for that Sea Foam. It, like antifreeze, makes a good weed killer.
--
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
 
Sea Foam can be used as a fuel treatment, it can also be injected straight into the throttle body. I spritzed a little starter into the Onan and it
fired right up. I guess a false alarm. Changed the oil after and she is purring along very nicely. I do think I can hear an improvement over what
she sounded like before the treatment. Like I said, it worked well on my older Wheel Horse tractor so I think Sea Foam is a good product to help burn
off deposits. See this video of a guy who tested it with a borescope to see before and after. He mentions trying other products and not seeing the
difference that he saw with the Sea Foam.

https://www.youtube.com/watch?v=WdT4DPFXIkM
--
-James Palmer, Traverse City, MI
1976 Eleganza
 
I use SeaFoam in my gas when the coach is going to sit for more than a couple weeks. Seems to work better than Stabil for me. I don't see a problem
with it and it comes highly recommended for this purpose from several mechanics I know that work on older vehicles. I've never used it direct into the
carb though. The guy at Pinellas Power recommends something else for injecting direct into Honda generator carbs and I used that to great effect. Some
kind of Mercury (marine engine) injector cleaner I believe. I think some of these "mechanic in a can" products do simple things pretty well. But
success seems to vary greatly among people that use them, not just across various products but across various users of the same product. Probably
depends on what you expect to get out of them.
--
Thanks,
Jeremy Knezek
1976 Glenbrook
Birmingham, AL
 
I never had auto shop class, but my friend always quotes his community college advanced engines class instructor--- if you have to add stuff to your
gas and oil , you are using the wrong gas and oil.
--
John Lebetski
Woodstock, IL
77 Eleganza II
 
> I never had auto shop class, but my friend always quotes his community college advanced engines class instructor--- if you have to add stuff to
> your gas and oil , you are using the wrong gas and oil.

Well, yes. But depending on how old you are, your instructor probably didn't have to deal with the problems of ethanol in gasoline in intermittent use
40+ year old engines. I agree that finding pure gas would be the correct gas to use, making your instructor absolutely correct, but it isn't so easy
to find, and what I do find tends to come from gas stations that might not have very clean tanks. Plus they charge an arm and a leg. So some fuel
stabilizer to fix the gas is a modern solution to a modern problem for not so modern engines.

--
Thanks,
Jeremy Knezek
1976 Glenbrook
Birmingham, AL
 
I've gone to great lengths (and expense) to use Ethanol free fuel (which up here always means premium) since I bought the GMC. Not sure what po have
used though. I'm hoping to replace fuel lines, clean up the engine/carbs and then feel some freedom to mix fuels depending on how long it will sit
between use.
--
-James Palmer, Traverse City, MI
1976 Eleganza
 
I have used seafoam to clean out countless old motorcycle engines. It works a treat if you use it correctly. It won't fix mechanical problems, but it
certainly cleans things out.
There's nothing wrong with using it in the Onan.
As for it getting into the oil, that's actually a good use for it as well, you can put some in the oil, run it for a while and then drain it to clean
out the oil galleys. You'd be surprised how much crud comes out of a 40yr old engine.
--
Justin Brady
http://www.thegmcrv.com/
1976 Palm Beach 455
 
> I've gone to great lengths (and expense) to use Ethanol free fuel (which up here always means premium) since I bought the GMC. Not sure what po
> have used though. I'm hoping to replace fuel lines, clean up the engine/carbs and then feel some freedom to mix fuels depending on how long it will
> sit between use.

James,

While I like the idea, but have you checked the gas you are buying?
Late last year the stations up there were found to be selling E-10.

To check it, get a 100cc plastic bottle at a pharmacy. Put 10cc of water in it.
Fill to the neck with gasoline. Shake it a while then let it sit.
That water will be at the bottom. If there is more than when you started, that is alcohol.

Matt

--
Matt & Mary Colie - '73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Still Loving OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Twixt A2 and Detroit
 
With the exception of the outdated rubber fuel lines that simply are not e10 compatible and must be replaced with barrier type, I have had zero issues
from e10 in any cars, GMC or the Onan. Small engines especially 2 strokes that don't get used regularly are another story. I quit using Stabil as well
but try to not exceed 9 months without adding fresh fuel.
--
John Lebetski
Woodstock, IL
77 Eleganza II
 
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