Re: Big Twin 35
If it's a '57, then there is no thermostat. It did not get one until '58. Otherwise, it would be under the plate on the head held on by three screws.<br />So for a '57, there should be no restriction felt at all if you were to blow up through the water tube. (Use a hose attached.

)<br /><br />The water should come out of the large hole on the back of the midsection. I belive some is also supposed to come down where the exhaust goes. If this doesn't work, and shoving a wire up the tube doesn't either, then you're going to have to remove the head and/or exhaust cover to expose the passages. But I don't think it'll come to that. <br /><br />Oh yeah, if it was a '58-, then you would have two water tubes for the water pump in the midsection.

<br /><br />I don't understand how carbon could have gotten into the system, unless it was from crud floating around in the bucket it was tested in. It's not chunks of an old impeller that flew apart is it?<br /><br />If your impeller is ok, then it's arms should stick straight out when you take it out of the housing like the one in this picture:<br />
Picture 1<br />
Picture 2<br /> <br />Good luck!