1984 Merc 25 hp XD dies at WOT

trendwalker

Recruit
Joined
May 22, 2004
Messages
4
I just bought this motor day before yesterday. I'm a newbie here and with outboards but like to work on my own stuff if I can. I'm much more familiar with Johnson and Evinrude so this motor stumps me a little bit. It runs like a champ but when you open it up it dies at full throttle. No gas left in the line or fuel filter. If I Pump the primer bulb a few times and she'll fire and go again until it does the same thing. If I keep pumping the bulb, she'll run wide open all day, but its a little tough to prime and drive at the same time. It appears that gas may be leaking out of the fuel fitting going into the motor as well.<br />Primer bulb?, Fuel pump?, air in lines? Something else? Where should I start? Any help would be greatly appreciated.
 

achris

More fish than mountain goat
Joined
May 19, 2004
Messages
27,468
Re: 1984 Merc 25 hp XD dies at WOT

If there is ANY air leaks in the fuel system then the fuel pump will suck air (as it's lighter and easier to suck). That means from the pickup inside the fuel can all the way to the fuel pump on the side of the carb.
It appears that gas may be leaking out of the fuel fitting going into the motor as well.
This would be a good place to start! Besides, gas leaking into a boat makes me nervous. Makes a big bang! If that doesn't fix it, then pull the carb and clean/re-diaphram the pump. <br /><br />Chris........
 

NathanY

Commander
Joined
Mar 16, 2002
Messages
2,408
Re: 1984 Merc 25 hp XD dies at WOT

Well check the obvious first. If it is leaking around a fitting, replace the fitting. If you still have to keep pumping it to run, then more likely then not, you have a tired fuel pump.
 

trendwalker

Recruit
Joined
May 22, 2004
Messages
4
Re: 1984 Merc 25 hp XD dies at WOT

Thanks for the reply. It's not a major leak if it is one, but definitely not one that I'll let go either way. <br />Any opinions on generic vs. OEM fuel lines? I'm going to replace the fuel fitting on the motor I think too, just because.
 

trendwalker

Recruit
Joined
May 22, 2004
Messages
4
Re: 1984 Merc 25 hp XD dies at WOT

I obviously need to pick up a manual so I can be more familiar with this motor, but for those who know already, is the fuel pump part of the carb?<br />Thanks for the fast responses and the welcome of people responding so quickly.
 

achris

More fish than mountain goat
Joined
May 19, 2004
Messages
27,468
Re: 1984 Merc 25 hp XD dies at WOT

I used to sell both types of fitting. We had so many returns with the generics we stopped selling them. <br /><br />Any help?<br /><br />Chris...........
 

Elmer Fudge

Lieutenant Commander
Joined
Aug 25, 2003
Messages
1,881
Re: 1984 Merc 25 hp XD dies at WOT

Hi trendwalker, also check your fuel vent,it's possible it may be clogged.
 

achris

More fish than mountain goat
Joined
May 19, 2004
Messages
27,468
Re: 1984 Merc 25 hp XD dies at WOT

Fuel pump and carb are integrated.
 
Top