carb frosting

[dwaine8633]

i have a solex 34/34 on my stock sammi.when it snows it would start flooding.took of the breather and noticed frost around the venturi.it almost covered it all except for the small center hole.is there any way to prevent this from occuring.any help please.

[GeoB]

Originally Posted by dwaine8633

is there any way to prevent this from occuring.any help please.

The only thing I can think of is either wake up, smell the roses and stay out of the snow, or maybe supply some carb heat. Most stock vehicles around have a provision for warming the incoming air. I don't know what would be the best choice, but I think I would look for something like the old Pintos used. They had a system that was self-contained. The air filter box, the inlet snout, ducting, whatever, kain't remember exactly what it looks like, had a built-in device that would open and shut the diverter door from the manifold stove, to keep the temperature at like 86 degrees (IIRC). I had a 1974 Pinto. 2300? I imagine some searching and some questions and stuff might find something similar that doesn't require computer control. I think the stock Samurai has a similar device, with an over-riding computer control. It may not be the computer, it may be a temp sensor or something, not sure as I sit here. Which could be removed. But it would prolly be too small as it sits, but maybe you could borrow parts and fabricate a larger one.

Probably this is a well-traveled road and what you want prolly is readily available. Maybe ask the VW people as they are into Solex and Zenith.

Maybe, like the airplane people, you might want a manual control on the carb heat. You could use it when needed only. I wouldnt, but some might like it this way.

It does cost you some potential power. Not like it consumes power, which would lower your mpg, but it provides a less-dense air flow so less O2 gets into the cylinder. But the warmth helps 'atomize' the fuel, thus contributing towards a more complete burn and better mpg. And a cleaner running engine.

[SKY HOOK ZUKER]

Originally Posted by dwaine8633

i have a solex 34/34 on my stock sammi.when it snows it would start flooding.took of the breather and noticed frost around the venturi.it almost covered it all except for the small center hole.is there any way to prevent this from occuring.any help please.

I have the same problem with my Webber. But it only happens in extreme conditions, 20 deg air temp and cruising 55mph which is almost full throttle. I plan to supply it with warm air but its hasn't been a huge problem yet. A manual system would work fine for me.

I own an UMP air cleaner and will be installing it this spring. Still haven,t figured out the best way to do the warm air option yet.

[cajunsuzukispider]

are you still using the stock heat-jacket around the exhaust manifold with it's tubing still plumbed into the stock air intake with it's little heat controlled valve? It may work for you if you're not. usually it's the first thing to go. But if it's that's cold, you probably need it. also, if you have that much moisture in the air at night, you may want to have the end of the air intake tube handy, so you can plug it at night and stop the moisture from becoming frost down in there. We're really humid down here in the swamp, but we don't see that kind of cold. right now it's about 75 and sunny. bet you northern boys are jealous right now. It'll be my turn when it gets 115 plus 145% humidity. I don't care what they say, the heat index is more like 200.

[dwaine8633]

thanks,i have been thinking of building my own breather that incorperates a powerstering cooler off of the original water choke lines.if i get it done i`ll post some picks.my sammy is a daily driver.40 miles to and from work.bad weather is the reason for pucharsing my sammy.freinds at work are enveous of my 28 mpg and supiror 4*4 capability.

[85sj413]

I have had this same problem in the fall on humid days.
On the highway at almost full throttle, the secondary had not opened up yet.....the venturi would start it ice up.

overnight frost is not the problem, think about how fast air is going through your carb, and what the wind-chill effect would be like, if you are having this problem you really need to supply the carb with warm air.

the sj410's used to have a wing nut, on the air box that you would adjust for winter or summer, the sammi has a thermal / vacuum operated baffle. maybe yours is not working.

note : i'm runiing efi now and will never go back to a carb.

later
Steve

[cajunsuzukispider]

One would think that the carb, sitting atop a water-cooled intake, would stay warm enough keep defrosted. And I think wind-chill only applies to things that evaporate water, like people. But it's true that fast moving air out of a valve stem will cool it tremendously and frost on the outside. I can't imagine the motor sucking that much air through there to do that. If you are, then you're getting good power with all that dense air charge.

[GeoB]

The evaporating fuel, as well as the expanding air create the low temps. I think primarily the evaporating fuel.

I don't think you can count on the air being denser; because it is being sucked into the manifold, which lowers the pressure, allowing it to expand and cool. Cool = dense, low pressure = not dense

The cooler and lower pressure maybe have a linear but opposite relationship which cancel each other out.

[Hijack on]
TBI injection makes for a heavier mixture in the intake runners, requiring more energy to get it all into the cylinder, compared to port injection. Dry intake runners have lighter air in them and this makes for big tuning differences. Also the fact that the fuel isn't present to be worried about puddling or something also effects the tuning possibilities.
I am building a MegaSquirt controller, thinking that one day I may switch from the TBI to port injection. 'Bout alls I would have to change would be to add bungs and injectors to the manifold.
[Hijack off]

But what do I know?

[patrickbuilt]

If you wand to get a good idea when carburetor icing is most likely take a look at the chart on this page http://www.ez.org/carb_ice.htm . If you are looking for a cheap way to deal with carb ice go to a local airport and ask an aircraft mechanic if you can look at how the systems work on small planes. It could not be made any simpler then the system on mine. The problem with planes is that the intake air when carb heat is selected to on position is NOT FILTERD at all. If you feel like building a manual control system that could incorporate a filter and only use it when needed.

[patrickbuilt]

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[patrickbuilt]

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