Exhaust Manifold Test MErcruiser 120

About to do acetone test on my exhaust mani and need to know if I need to remove the caruretor mounting plate boldted on the manifold (see pic) to do the test.

Thanks for input,

trm

I think I may have discovered the leak in my water system. A corner of the riser showed a trace of rust and, as you see in the pic, it was completely broken and held in place by the bolt. I will also test the manifold for leaks with acetone meaning that I still need to know if I need to remove the intake manifold for testing the exhaust manifold (referred to above as "mouning plate"). Does the intake manifold have water passages? If so, will the acetone destroy the gasket between the intake and exhaust manifolds?

Thanks for all inputs,

trm