Hi,
I'm new to boat engine troubles but generally a versed mechanical person. I recently aqcuired a pontoon boat with a '78 mercury 402 2-stroke 40HP engine. Before launching it I checked over the engine, checked compression, cleaned the carb, replaced gear oil in lower unit etc. and ran the engine with flush cups. I did not get water out the tell-tale pipe (pee hole). Dropped the lower unit to find the impeller in shreds. I replaced all water pump parts twice now (seals, gaskets, impeller) except for lower and upper housing which appear in perfect condition. Still no joy. I checked the water pipe going from the pump to the power head and blew air through it to make sure there are no restrictions. Appears clear - Air is coming out the tell-tale pipe.
I dropped the lower unit again (third time now) to double check everything, impeller is still good, all seals are ok. Water tube going to the power head was inserted correctly (did not slip past pump housing). Blew some air into the tell-tale tube, plugged the bottom end of the water tube (that normally connects to the water pump) and could hear a significant air leak inside the gear housing below the power head. I talked to a mechanic and several other boat people about the possibility of a leak on the underside of the power head where the water tube connects but everyone says 'no, that's very unlikely'. But I'm running out of options.
I looked up the prints and see there is a seal there but looks impossible to get to without taking the power head off. Anybody have any ideas or siggestions?
Thanks,
Mike
I'm new to boat engine troubles but generally a versed mechanical person. I recently aqcuired a pontoon boat with a '78 mercury 402 2-stroke 40HP engine. Before launching it I checked over the engine, checked compression, cleaned the carb, replaced gear oil in lower unit etc. and ran the engine with flush cups. I did not get water out the tell-tale pipe (pee hole). Dropped the lower unit to find the impeller in shreds. I replaced all water pump parts twice now (seals, gaskets, impeller) except for lower and upper housing which appear in perfect condition. Still no joy. I checked the water pipe going from the pump to the power head and blew air through it to make sure there are no restrictions. Appears clear - Air is coming out the tell-tale pipe.
I dropped the lower unit again (third time now) to double check everything, impeller is still good, all seals are ok. Water tube going to the power head was inserted correctly (did not slip past pump housing). Blew some air into the tell-tale tube, plugged the bottom end of the water tube (that normally connects to the water pump) and could hear a significant air leak inside the gear housing below the power head. I talked to a mechanic and several other boat people about the possibility of a leak on the underside of the power head where the water tube connects but everyone says 'no, that's very unlikely'. But I'm running out of options.
I looked up the prints and see there is a seal there but looks impossible to get to without taking the power head off. Anybody have any ideas or siggestions?
Thanks,
Mike