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Posted on Apr 27, 2009
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Having trouble with my 1974-78 outboard marine engine

Motor starts up quickly after a long winter. I've been having trouble when boat is in water. Motor after a couple of minutes, water temp increases and motor overheats itself. When traveling above 8- 12 knots water pump is not pumping strong as it was when I was in neutral or traveling below 8 knots. I also find when I'm accelerating the motor tends to **** down as if its de-accelerating and rpm's are having trouble to climb. I changed the water pump last year I cleaned carbs I took off one of the heads and cleaned it and replaced gasket-no problem Do you think I have a thermostat problem.... because I noticed the water gets hot as well as the hoses leading into the heads. ( I started the motor for the first time this year on land with water attached to boat I pulled one of the hoses attached to thermostats leading into head, noticed water was hot after running for 2 minutes) What can I do? Please help? P.S Bought a knew prop, had it professionally measured specifically for my engine/boat. Had problem before knew prop too!

1 Answer

Jerry Koski

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  • Mercury Master 443 Answers
  • Posted on Apr 27, 2009
Jerry Koski
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Joined: Jan 25, 2009
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Just an idea but your water pump is only rubber and setting for the winter it didnt stick to the sides of where it pumps did it.. sometimes these pumps are tempermental.. you might check your water pump again making sure its pumping right.. is it peeing out the sides good like it is suppose to ? also if its getting hot on top it makes me think the pump is not doing its job right maybe just pumping some.. not enough? just a thought .. thanks Jerry

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