1999 75 hp carb problem

caverun

Recruit
Joined
May 14, 2009
Messages
2
ok here we go the engine from hell i have been fighting this thing all summer. this is what is going on here, at the house it will run fine, take it to the lake 3 miles away it will not start . it is flooding out. if i unplug the gas line it will start after i crank it long enough . but as soon as i plug the gas line back in, it floods out and will not start again. now when i come home again it still will not start . until the next day after it has sat for some time in the upright running position then it will start right up no problem , start over and over. the only thing that is changing from here to there is that the engine has been tilted forward while i go from here to there. so what could be going on with the engine tilted that will make it not start that fixes itself sitting in my carport. the carb's have been cleaned 2 times . the few times that is has stated when i get to the lake , it has run great . please help if you can . tom
 

Frank Acampora

Supreme Mariner
Joined
Jan 19, 2007
Messages
12,004
Re: 1999 75 hp carb problem

Oh! You have a very valuable engine! It is a collector's item because Mercury made a special run of a very few Force engines that were allergic to water--LOL

Check the enrichment valve and be sure the red knob is not in the manual choke position. Unplug the enrichment valve wires to see if it is stuck open. Clamp the hose from the bottom of the carb with a Vice-grip pliers and see if cutting off fuel flow that way helps.

Check the fuel pump diaphragm for pinholes in the rubber.

Lastly--yes, I know you have cleaned the carb a gadzillion times. HOWEVER remove the inlet fitting and manually clean the inside and bottom of the seat. Use a pipe cleaner and spray WD liberally. A little piece of un-noticed crap there will hang up the inlet needle and cause flooding. Then when it sits, it clears out until you try to start again.

Do NOT use any permatex or teflon tape on the threads when you reassemble it---that's just asking for trouble! (If there is any on there now, clean it off--thoroughly)
 

Stefano

Cadet
Joined
Jan 29, 2010
Messages
19
Re: 1999 75 hp carb problem

Let me know if it works cause i have a 1999 Mercury Force 75 hp and i'm having the same problems as you and its driving me crazy . Thanks Stef
 
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