My neighbor's Tohatsu 50 is not running right so he asked me to help him out.
The issues are this motor idles rough, dies at idle at times and surges intermittently at cruise.
He ran it thru some sand/mud 2 years ago and overheated the engine. He had diagnosed by a local mechanic and he found low compression on the #2 cylinder and water on all plugs. He installed a new head and gasket and cleaned the exhaust plates and installed a new exhaust cover gasket. The motor ran well at first but the performance has been getting worse over time.
The first thing I did was pull the plugs and I have never seen plugs in this condition. They are a brown/tan almost rusty color and really look like they have been sitting in water. The middle cylinder was the worst of the three.
We put in new plugs and ran the boat at speed for around 20 minutes and the afterwards the new plugs looked nearly as bad as the old. Could the head gasket be leaking allowing water into the cylinders? Compression is 120 on the top and bottom cylinders and 115 on the middle. Any insight would be appreciated.