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Onan: 1976 15 jc

luc102

Registered
Hi guys.. a kwik question
I noticed when i run my genset the carburator tends to freeze up .. is that normal or is this something i should worry.. it runs fine from no load to full load .

We are in full winter mode here but I also noticed it in fall.. thanks
 

VelocityDave

Subscriber
Last Subscription Date
06/23/2019
Whenever it was cold and damp either rain or snow my JC gave trouble with the carb icing up. The rpm would drop so hertz and voltage would drop. I ended up making a home made carb heater setup like Onan had on the JBs and JCs. This ended my carb icing problems. For anyone wondering ice builds up in the carb venturi blocking air flow. Ice would also block the throttle shaft from moving.

David
 

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luc102

Registered
Wow .. thats nice and not to hard to build... thanks i might just make myself one.. although its not giving me any problems but wont wait for it..
 

Mike57

Subscriber
Last Subscription Date
07/14/2019
Really nice work. What materials did you use for the tubing? The painted center section looks to be an air volume control? What did you use to make that?
 

luc102

Registered
I was also wondering...

my jc is in a very sealed enclosure ( no rodents in there ) but it is outside and not heated .. when i brought it back to life i sealed all electric and electronic components and connections with a clear lacquer .. also cleaned up gen end with small brittle brushes and re-sealed with lacquer.. the original varnish was all falling off .. that being said..

what are the consequences of being exposed to about 2 weeks of -20 c ( 16 to 18 f ) and many below zero days .. i noticed it get Full of frost .. i may insulate for next year and heat a bit..
I run it every week for 30 min. With a 40 amp load .


ive started it after 2 days of - 20 c and it just went but is there issues with wirring and connections and the controls ( vr, relays, ) keep in mind they have all been sealed in 2-3 coats of clear varnish even on the reverse side of the vr.. are those gensets made for that enviroment or its a ( nono ) .. thanks
 

VelocityDave

Subscriber
Last Subscription Date
06/23/2019
Really nice work. What materials did you use for the tubing? The painted center section looks to be an air volume control? What did you use to make that?
The hose is silicone preformed w/ 45 and 90 degree bends sold on eBay in all needed sizes and it’s cheap. The green painted part is a temperature control Onan part. I don’t know what it fit but it was the same as the one used on a JC but it had different mounts. I just cut the mounts off and didn’t put any back. To me the hardest thing was closing the bottom of the air filter and installing a tube for the hose to slide on.

David
 

turtmaster

Subscriber
Last Subscription Date
10/03/2019
Can you please post some pictures later, on how you closed in the bottom of the air filter housing, to add the fitting to the intake air preheater. Thanks!

I need to do this and of mine, except I'm going to leave it preheated all the time, because even on a 70 degree, day, if I use E10 ethanol gasoline, I can still get the carb icing, and have to open the main jet and additional half turn.
 

VelocityDave

Subscriber
Last Subscription Date
06/23/2019
My carb would freeze on days when it was humid. Some days the generator would cut completely off. Some days I would here it slowing down. When it cut off it would unfreeze and I could restart it and it run ok for a while. The tubing is 1 3/4” od and naturally the hose is 1 3/4” id. I think this is the same as factory size.

David
 

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Max Thompson

Sponsor
Last Subscription Date
09/03/2019
Darts: I notice your filter housing bottom has an open section in it. Onan also built these with a "solid" bottom, like Dave built for his.

Do not mix up these parts and use a solid bottom with a cover that does not have the hose connection. Your engine will very quickly STARVE for air. (No need to ask how I know this) :rolleyes:
 

VelocityDave

Subscriber
Last Subscription Date
06/23/2019
Wouldn’t a open bottom filter base pull air away from the carb with a vaccuflow cooling system? I can see it working with a pressure cooling setup. The original pictures that someone sent me that I copied mine by was vaccuflow. It was closed. I didn’t realize Onan used either bottom cover.
 

nothingbutdarts

Sponsor
Last Subscription Date
08/15/2019
^ ^ ^ ^ ^ It doesn't need to look new to work like a charm! It has so called patina. As long as it is maintained and works is good for me. Each to their own here at the STAK. Lots of very sweet looking machines here, some almost new and some made to look new. It's a 3 phase and not extended stack so, only good for about 50 amps. a leg.
 

luc102

Registered
^ ^ ^ ^ ^ It doesn't need to look new to work like a charm! It has so called patina. As long as it is maintained and works is good for me. Each to their own here at the STAK. Lots of very sweet looking machines here, some almost new and some made to look new. It's a 3 phase and not extended stack so, only good for about 50 amps. a leg.
great look .. since you mentioned patina.. and i did not intend any diserespect.. we are all proud of our sets..looks are only superficial
 
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