1991 mercury 25 hp

[beefey]

i have a 91 merc out board 25hp i have to pump the primer ball to keep it running so i was told to put i a new fuel diaghram in it so i did and it still wont stay running i still have to pump the primer ball to keep it running when it runs to runs graet till it runs out of gas and i pump the ball

 

[will941s]

Re: 1991 mercury 25 hp

Disassemble and clean the carb, make sure the diaphram and carb parts are installed correctly, and everything has a good seal and no air leaks. Also check ALL your fuel lines for any kind of leaks, even small ones. If they are even the least bit sketchy replace them. Also make sure the pick up tube in your tank is'nt catching air. If all that checks out then you should be good to go.

 

[Jacket4life]

Re: 1991 mercury 25 hp

If the ball won't stay hard, you have a fuel delivery problem of some sort. That's just the way it is. Start at the tank and eliminate each part through inspection or replacement. You can start by pumping it hard then waiting 2-3 mins. If it is soft again, you pretty well know your problem is before the engine, unless you made a major mistake in replacing your diaphragm.

Best of Luck!