Onan Problems -Carburetor ICE

[richard waters]

So I am not alone with Onan problems. My 6000 watt Onan
runs like Stephen's does. Part of my problem I believe is caused
by carburetor ice.

Today prior to putting the coach is storage, I decided to run the Onan
with the drawer out. I started it up (temp today was about 40 and
very humid). Within a few minutes I could see the carburetor
start to get white with frost. Gradually the frost began to cover everything
from the venturi to about 2 inches into the intake manifold. That's when
the Onan started to really load up and exhaust black smoke like Stephen
describes. After a few more minutes it finally stopped.

I waited about 10 minutes for the ice to melt and restarted. It ran fine
for another 15 minutes or so then the same problems.

Carburetor Ice! I think that explains a lot of my recent problems. I think
there is a kit or something that can be made to heat the intake air during
cold weather. Anyone have any suggestions?
Richard Waters '76 PB, Troy, MI
- ---

> My '76 Eleganza 6KW Onan runs extremely rich under load. Sometimes it sounds
> like it cleans up but when the throttle cracks open then smell, black soot,
> obvious very rich condition. Remove hose from air filter, held choke open
> manually so am sure there is no restriction. Adjusting mixture makes no
> difference. Removed float bowl and it looked clean inside, no buildup of
> varnish as expected. Needle and seat look OK visually, various adjustments
> of float level resulted in either no fuel flow or the rich condition. Onan
> lists the carb repair kit and replacement carb as No Longer Available.
> Golby's said they would mess with it but they have had the carb since
> Thanksgiving so I am going to ask that they ship it back.
> Camper World checked out the generator and it operates fine but they
> couldn't do anything with the carb. I have not been able to find anyone in
> the area (Dallas Ft. Worth) that can help, guess we are too remote.
> This Lurker is looking for some advice.
> Stephen near Denton, TX

 

[dave mumert]

Hi All
My Onan has a cold weather kit installed on it. I had to get a replacement
hose so it would not ice up on New Years eve.

The air cleaner is covered with a cylinder that has a 1.5 inch hose fitting.
There is a hose between the air cleaner fitting and a scoop that fastens on
the engine baffle. I don't think it picks up exhaust heat. It looks like it
may pick up cylinder head heat or cooling air or ?? There is a decal saying
to remove the hose above 50 degrees. I used flexible exhaust pipe for a
hose but I will be ordering some SCAT tubing as soon as I get a chance.

I didn't pay that much attention and I have not looked that closely at a
standard Onan When I get a chance I will try and get some pictures. I may
need a cold weather kit for myself before I do that .

Dave Mumert
dave

- ----- Original Message -----
From:
To:
Sent: January 09, 2000 7:54 PM
Subject: Re: GMC: Onan Problems -Carburetor ICE

>
> > Carburetor Ice! I think that explains a lot of my recent problems. I
think
> > there is a kit or something that can be made to heat the intake air
during
> > cold weather. Anyone have any suggestions?
>
> Richard,
> There was a kit to shroud the air cleaner and pick up warm air from
around
> the exhaust. It is not in the 78Z parts book, but was reported in a
service
> bulletin (76-IM-16, July 1976), Part # 2018248 for 6KW Onan, # 2018249
for
> 4KW. Had to be "partially removed" above 50 deg. F. When I inquired of
> Cinnabar about it a couple years ago, they said it was no longer
available.
> I can barely make out what it looked like from my faded Xeroxed service
> bulletin, but this might be a good project for one of our sheet metal
> wizards. ??
>
> Rick Staples
> '75 Eleganza
> Louisville, CO
>

 

[richard waters]

Rick,
Thanks for the reply.

Now that you mention it, somewhere in the pile of GMC stuff that the PO
gave me there is mention of how to make a winterizing kit for the ONAN.

I'll look for it and let you guys know what I find.
Richard

>
> > Carburetor Ice! I think that explains a lot of my recent problems. I think
> > there is a kit or something that can be made to heat the intake air during
> > cold weather. Anyone have any suggestions?
>
> Richard,
> There was a kit to shroud the air cleaner and pick up warm air from around
> the exhaust. It is not in the 78Z parts book, but was reported in a service
> bulletin (76-IM-16, July 1976), Part # 2018248 for 6KW Onan, # 2018249 for
> 4KW. Had to be "partially removed" above 50 deg. F. When I inquired of
> Cinnabar about it a couple years ago, they said it was no longer available.
> I can barely make out what it looked like from my faded Xeroxed service
> bulletin, but this might be a good project for one of our sheet metal
> wizards. ??
>
> Rick Staples