I took the heat riser apart today and it was stuck in open position but i managed to get it working after a lot of oil and bending forward and back... When i checked the shopmanual, i noticed that there is a part missing from it, its not possible to see it clearly in the manual , to me, it looks like a bimetallic piece, just behind the spring on the opposite side of the weight and i think that its necessary to have it, if it should work properly, or??? Does anyone know if its possible to buy spare parts for the heatriser or do i have to search for a new one??? I also wonder why the exhaustmanifold has a small tube fitting just pointing straight out, it is about 1/5 of a inch and is located just over the heatriser in the forward direction and it is nothing attached to it??? The choketube goes to a similar fitting but on the opposite side... Someone???
Sorry for the bad drawings but computers is not my favourite hobby ... I am missing the piece that looks like a 8 beside arrow nr 1, but the spring is still in place, what is it for and do i need it??? On my exhaust there is also a tube fitting sticking out 1/5 inch around arrow nr 3, i cant see the same fitting on ypur photo but i guess that it is there somewhere, its similar as the tube fitting close to arrow nr 2... Kind of difficult to explain but someone hopefully know what i mean... Thanks Jannelu
I think #1 is an "anti-rattle" spring, intended to put a side load on the shaft to keep it from making noise due to engine vibrations. Mine looks different than this so I could be wrong. #2 and #3 are opposite ends of a tube that runs through the exhaust manifold. The carb draws air through the tube, which gets heated by the exhaust. This way the carb is not sucking exhaust gas, which would quickly sludge up the carb and tube, only heated air. There should also be a twisted strip of copper inside the tube to help with heat transfer to the air. So, one side goes to the choke housing, and the other side is open. Hope this helps.
Sounds like the piece your missing is the heat riser tube for the hot air choke. Has yours been converted to an electric choke?
Txgwildcat, thats exactly the piece that i am missing!!! Is that the bimetal that close the valve??? My heatriser moves freely now, but its open when i keep it in roomtemperatur and it wont close when it get hot either so maybe thats the part that i need??? My heatriser is also complete with the small antirattle spring on the same side as the weight and i also have the big spring on the other side... I also have the tube for the heatriser choke connected (it is not converted to electrical choke) and now i clearly see what the other tube looks like... I have also posted the same question at Aaca.org and Ted Nagel described that the other tube should be connected to the carburator and that its for clean air... As i mentioned before, on my manifold i only have the choketube and not the freshair tube so i have to fix that also... Thanks a lot, especially for the nice pictures... Jannelu
Jannelu, The heatriser should close when cold, open when hot. If you're going to get all this working, you need to also check the passageways in the intake manifold. I've got two intakes laying around, and they both have the passageway under the front of the carb blocked with black junk.
