Re: overheating....?
It does sound like you don't have enough water being pumped through the engine. What engine and drive? Small engine can mean small amount of water, big engine will mean a whole lot more. I think we are assuming its an open cooling system. Has this been creeping up on him or has it happened all of a sudden? If he doesnt know the last time the water pump was serviced than I would start there. You can test it but if you don't know the amount of water it 'should' be pumping than your fumbling in the dark a bit. I would set up a test drum and lower the drive into it, loosen the pipe from the pump to the engine and start it up, remove the pipe from the engine and you should have a strong stream of water from the pump. Go from there, if it seems plenty than repeat the test at each point along the way until you find the source of the restriction. May just be a faulty thermostat but I would start at the pump and work your way through the whole system. Scale and rust buildup can sneak up on you and than one day you have an engine thats over heating! Dont run the engine to long without water, 10 to 15 seconds should be plenty long enough for each test to gauge the flow and determine if there is restriction at any point or not. If the pump turns out to be not delivering a strong flow of water than work back from there, check the fittings for scale and rust, does it run through an oil cooler first before it gets to the pump? If so by pass the cooler and try it again. If that checks out than rig up a hose direct from the suction side of the pump to the test drum. If you get good flow from doing that than its likely the leg is the problem. If thats the case than you should be right with the advise that will flow your way from this forum from there. Good luck!
