if your leaking coolant wouldnt a leak test tell you, will you see bubbles come up in the rad. or do a
leak test on the rad, that will tell you if you have a leak, i think that most auto part stores have
one you can rent or use, but your uncle prob has one in his shop. but have you tried a different carb yet.
i might have one i can let you use to see if thats the problem.