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Hi.
The heat riser bolt in my 84 302 has rusted off. The unit is hanging there with the vacuum line off of it swinging in the breeze. I can't quite see a way to wire it back in place, and I dread installing a new unit because everything is rusted and I am working in my driveway. What does this thing do, and is it hurting me not having it operate. The gate inside the unit moves freely by hand. Thanks,
When the engine is cold, it blocks the exhaust from going out on that manifold, and forces it to run underneath the carb to the other side. This warms the carb and the intake up very quickly, so you can drive off without it bucking and stumbling when the engine is cold and it's cold outside.
In my experience, if you have the original aircleaner with the warm air pipe going to the stove around the exhaust manifold, and your vacuum lines are hooked up and the divertor door in the snorkel of the air cleaner is working, you can get away without using the heat riser without too much affect, maybe just a little bit of stumble.
If you have a chrome aircleaner or none of the original stuff on the aircleaner is hooked up and working, you had better get the heat riser working. Or you will have a cold natured engine that doesn't want to run when it's cold outside.