82 70hp 3cyl 2 carb outboard

Hullfam83

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Aug 8, 2015
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5
70 hp 82 mercury 3 cyl 2 carb replaced fuel lines gas can fuel filter put new gasket set for fuel pump cleaned carbs thoroughly engine goes good off start then bout 20 to 30 seconds later dies from lack of fuel I'm stumped please help
 

Hullfam83

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Aug 8, 2015
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Valves move freely inside and replaced all gaskets any ideas how to check there's enough vacuum to pump?
 

Bill kubiak

Chief Petty Officer
Joined
Jan 31, 2004
Messages
629
The fuel pump works from vacuum suction pressure created by the pistons on the up stroke pulling fuel into the pump and the downstroke creates a pressure pushing on the diaphragm which will force a small check valve in the pump to close and the fuel in the pump to be pushed into the carbs. Might be a good idea to rebuild the fuel pump. The parts are fairly cheap, I recently did mine and the parts cost me around 22.00 bucks
 

Hullfam83

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Aug 8, 2015
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5
Awesome not much to er 2 valves and some gaskets where u find kit? Kinda impossible for it to run so good with blown cylinder if you pump ball it runs like its supposed to when you stop she surges like its not pulling enough gas
 

Bill kubiak

Chief Petty Officer
Joined
Jan 31, 2004
Messages
629
I have a Merc dealer a few miles away, he either has the parts I need or gets them in a few days, but I pay a premium price for genuine Merc parts, check eBay,, good source for Merc parts, you want Merc Quick Silver stuff, not Sierra, Sierra is cheaper and I do not know how good the quality is....
 

Hullfam83

Recruit
Joined
Aug 8, 2015
Messages
5
Thank you very much for help if it doesn't fix problem may hafta get electric pump
 

Bill kubiak

Chief Petty Officer
Joined
Jan 31, 2004
Messages
629
Good luck,,Do you know anything about my issues, look down for my post about hot or too hot
 
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