Vangard engine intake frosting over

Anyone run any Briggs Vangard engines in the winter have the intakes frost over ? These are 27 and 35 hp models. If you have how did you cure it ? One of our customers is complaining about this as it also makes them misfire when this happens.
I'd say like an old tractor they might have to make up a deflector to blow hot air over that area.

I had a similar problem with a generic engine replacement on a snow thrower. I removed the air cleaner (not much dust in the snow) and welded up a pipe that took air surrounding the muffler. Later had to add a screen 'cause it wasn't tight enough and the mice stuffed it with nuts.

That is normal operations of any gas engine and that is why cars and trucks have a tube going form the exhaust manifold to the air intake so as to pull in warm air so as to stop the icing up of the carb and manifold. So the only way to help the problem is rig up some way to heat intake air

Mike, when any liquid changes to a gas, it requires heat energy. Take freon, when it changes form a liquid to a gas it removes heat energy from the surroundings. It makes the copper evaporator cold.

I've seen many engines ice up. I have a pic of my farmall C frosting up. I pull heated air off exhaust manifold on Jubilee and send it via a 4 inch aluminum close dryer pipe to the intake. Keeps the intake air around 80.

Old private single engine air craft pulled heated air off exhaust and sent it to the car. Plane even had a thermometer to pilot could regulate carb air temp.

Do you remember the cars in the 70, they would do the same thing, pull hot air off exhaust manifold and sent it to the air cleaner. When the are got too hot, a damper would close and bring in cold air.

If it an issue, make some way to extract heat off muffler and send it to the air filter.

MANY years ago on the "I" series Mc Culloch saws they made a little adapter just for that. Little tin box that had extra long stud on muffler. The cover had a metal tube that went up into the bottom of the air box after you drilled a hole in the bottom of the box for that tube. You get the air from the flywheel fan plus hot air from the radiated heat off of the muffler. Going to take some handy dandy cobling. Call Briggs and Stratton and ask for tech support. They might already have some gizmo you can buy. If not the muffer gets pretty hot and a #10 Can shield with a short piece of metal conduet tube spot welded together should do it. You only need some warm air introduced.

Manifold Heat Riser flapper valve as I recall. Biggest PIA as they always froze up and that was in S. Texas where they didn't ice the roads. Question was, in what position would they freeze. That and the linkage fast idle hootus on the side of the carb. I couldn't wait for fuel injected gas engines to come along.

Tex, not sure we are talking about the same thing. My old slant 6 had a flapper that diverted exhaust against the bottom of intake manifold. I called that the heat riser.

There was another vacuum activated flapper on the breather and a 2 inch aluminum flex tub that sucked heated air off the outside of the exhaust manifold. That flapper vacuum motor was thermostatically controlled so in summer the flapper was closed and no hot air need.

Bottom line, if an intake is frosting up, engine is having difficulty running, need to figure out a way to warm up the air before it goes through carb, don't you think?

Of course some air cooled engines are not using plastic intake manifolds so be careful not to over heat air.
geo

Cool air moving through the carb is like a wind chill factor. Even the 10 hp snow blowers dont run an air filter and use a shroud around the muffler to direct warm air to the carb.

As I recall, one of my engines, may have been the '71 chevy tub I spoke of earlier had a thermostatically controlled flapper in the snout of the sheet metal air intake where the filter is mounted on top of the carb. Or maybe it was vacuum controlled......I vaguely remember having to remove a vacuum type hose when it was removed....I think it connected to a metal tube adapter in the top of the intake manifold using manifold vacuum as it's "motor".

There was a paper and alum tube roughly 1 ? to 2" that came up from a piece of tin on the exhaust manifold and connected to a vertical tube protruding out of the bottom of the cover behind the temp sensing butterfly. On top was some sort of round cap hootus about 2 ? to 3" in dia.. Below certain temps the carb would suck in manifold heated air and as the engine warmed up the butterfly would open the normal cool flowing port and close off the manifold air..

The other one we called The manifold heat riser. There was a (this is 40 year old memory trying to surface here too) butterfly in one of the exhaust manifolds on the V8 that was supposed to be closed during cold weather. Job was to close off (spring loaded allowing fast acceleration of engine to force it open if necessary) that manifold and force the hot exhaust air back and through a passage in the intake manifold below the carb, to heat both, routing it over to the other side and out the tail pipe. That's the thing that usually stuck and it stuck shut, closing off that side and impeding performance.

So add those to the one that operated the choke butterfly contraption with it's stepped, movable stop and all.

So I guess over the years there were 3 manifold associated tricks Detroit tried to heat engines when cold to which I was exposed. Geez what a mess.