770 carb

Harryaroo · Jul 23, 2016

Looking at a 1961 Oliver 770. I already have a 65 770 so am familiar with the tractor. The current owner says the carb is icing up and making the tractor run rough. I think I roughly understand what causes this-- venturi effect --but am wondering what the most likely solution might be. I have read about applying heat via various methods to the carb but it would seem that if the carb is working right it would not ice up under most conditions. Will this likely be fixed by rebuilding/ cleaning the Marvel-Schleiber carb or will it be more complicated than that?

kevinecwi · Jul 23, 2016

Every gas Oliver we've had on the farm 1650,1550,880 would frost on the outside (above) of the carb. I doubt rebuilding the carb is goin to help IMHO.

old · Jul 24, 2016

Carb icing is a fact of life and some time making it a tad bit richer helps or rigging a way to use exhaust heat to keep it warm helps. That is why many older cars had a tube running form the exhaust manifold to the air intake that way warm air was pulled in to keep the carb form icing up

jh105 · Jul 24, 2016

There is a heat exchanger built into the intake manifold right above the carb. It's got the word "Oliver" cast into it. Exhaust flows through this area, and I've been told this was designed to heat the intake manifold and prevent things from frosting up so bad. sometimes this area of the manifold will fill up with rust and crud, thus reducing it's effectiveness. Probably the only way to really clean this out is to remove the intake manifold. this might help. also you might try and inline filter, and check sediment bowl for water that might be getting to carb.

770 carb

Harryaroo

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kevinecwi

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old

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jh105

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