Home › Forum › Ask A Member › 9.9/15 impeller housing tricks? › Re: 9.9/15 impeller housing tricks?
Another great point Dan. Yes, on most of the smaller OMCs, the overboard indicator is on the exhaust manifold which is at the beginning of the cooling cycle (except for the 4hp models). Sooooo, a plugged thermostat would NOT affect the flow through the pisser/overboard indicator.
This brings us back to the pump/grommet/or something before the exhaust manifold. I suppose a blown head gasket, or perhaps an exhaust leak into the manifold cooling passage might affect indicator performance, but that is a longshot and I think you would be seeing water on the plugs.
Not trying to minimize things, but it is real common to get crud caught in the indicator elbow.