carb frosting up on super 88

pllr

Member
Having issues with carb frosting up, usually I run tractor for a few minutes, carb frosts up, I shut it off, wait till it defrosts, start up and is good. had happen yesterday morning, frosted up, leave sit for a few minutes, then was good, I have snow bucket mounted on tractor, I pushed snow for about half hour, no issues. last night went to move more snow, we got 18 inches yesterday, same issues of carb frosting up. went through 3 cycles of starting, thawing, and back to starting. After tractor sits a few minutes, go to start it up, runs smooth till carb frosts up. Then spits and sputters, occasional backfire. In the past I have added a bottle of isopropyl alcohol to gas tank and gets rid of moisture, I also removed drain plug at bottom of the zenith carb to drain any possible water out. Not having any luck getting it straightened out, looking for more options... Thanks
 
You've got moisture coming into the carb via the fuel. Can you get the tractor inside or get it to where you can apply heat in the general location? Be mindful of the highly flammable nature of gas when using heat sources. Make sure gas is not fuming. Get more dry gas into the system. Shut off fuel flow and drain fuel bowl so any water is removed from that point. Some tractors have had the fuel bowl assembly removed in favor of an inline filter but that does nothing in terms of water separation.
 
Here is the site that I forgot to add! https://www.hemmings.com/magazine/hcc/2015/03/Carburetor-Icing/3747511.html
 
That was a problem on some of the early 1600 gas tractors, in fact Oliver had a "kit" that you installed on the tractor to preheat the air and it solved the problem.
 
put a coffee can over the muffler - put a hole in it to do so then put a hole in the upper side of the can to receive a pipe three inches long -- same diameter as the intake pipe -- put a flexible pipe of some sort from can to intake up to the can -- suck warm air off the muffler into the intake pipe -- problem solved -- no more frosted intake -- engine will run warmer too!! Roy
 
(quoted from post at 15:51:21 02/13/19)
I think that is a normal cold weather reaction. Very cold air goes through carb and up venturi and cause a pressure drop, turns very cold and frosts out side of carb housing, mine all do that. You can heat air going into carb would be a help. Heating outside of carb just masks the frost. Same thing happens when you try to spray early on some cold mornings and nozzles freeze up, the pressure drop across the nozzles cause ice to build. Tractor is just saying "baby its cold outside"
Dave
 
well it sounds like you need the reverse of what most complain about, too much heat being drawn in...I'd look at getting the heat from the exhaust to help. it maybe someone already addressed the hot air issue and that's the problem.

there's a reason air filters on cars are not on top of the manifold anymore...too much heat is being produced under the hood requiring a cold air intake. A shield over the carb and manifold should trap enough heat.
 
Would it help to clean the carbon / rust out the bottom of the exhaust manifold where the intake and exhaust bolt together? This seams to transfer more heat from the exhaust to the intake. I think it helped my Super 77.
Thanks
John Schoenauer
 
Would the louvered engine panels from an 88 fit on a Super 88?

Engine covers like a sheet of corrugated cardboard or thin plywood from the radiator to behind the carburetor will funnel heat from the radiator over the carb. Covering 80 to 90 percent of the front grill and engine covers on both sides of the engine would be ideal.
 
I pulled the carb yesterday, took it a part, took out the 3 small jets/orafices and cleaned everything up, there was a considerable amount of dirt in the bottom of the bowl, put together and got running, somewhat, managed to move a little snow, back into the shed, changed out the plugs, then ran much better
 

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