Help! Fuel deprived 25hp mid 80s Mercury

[Un?luckyangler]

I have what I believe is a 20hp mid 80s Mercury with a 25 hp carb thrown on. And maybe I'm wrong I'm just having trouble finding parts via serial #OA736753. Carberator part # is literally punched out and missing a number.
Got the motor when I was fairly young and ran well when we first got it. Recently the motor isn't getting enough gas unless it's choked. To the point where you need the choke to start it until it's in gear. Otherwise it won't start or bogs then kills. I've went through the carb a few times, check to make sure its getting good spark, fuel lines/filter aren't clogged, and new gas. Now I've been messing with idle screw, but that doesn't necessarily do much.
Any ideas?

 

[fastjeff]

Is the hole in the carb gasket lined up with the hole in the crankcase?

Jeff

 

[Un?luckyangler]

So the previous gasket did cause some blockage, so I cut a new one. It sits well but still having same issues... Probably going to let carb soak in a seafoam/carb cleaner mix for a day or so then run back through it. Just leads me to believe that there is still some type of clog in a jet

 

[flyingscott]

So the previous gasket did cause some blockage, so I cut a new one. It sits well but still having same issues... Probably going to let carb soak in a seafoam/carb cleaner mix for a day or so then run back through it. Just leads me to believe that there is still some type of clog in a jet

There are 3 different base gaskets that come with the carb kit. What did the gasket block? Was it the main intake hole or the 2 smaller holes that need to be OPEN. The same gasket kit is used for the 6/8/9.9/18/20/25 hp motors.

 

[Un?luckyangler]

It was one of the two smaller holes. Definitely an improvement, but still won't stay running without the choke. Double checked my tank, hose, clamps around the ball, and the quick connect valve from my tanks hose. can't hear or see any leaks from my tank hose, fuel filter stays full and ball stays hard.

 

[flyingscott]

What happens when you pump the primer ball on the fuel line?

 

[Un?luckyangler]

Ball gets firm and stays firm. Fuel fills up the fuel filter. As I run the motor with choke on, that fuel filter doesn't stay completely full. More like 1/4 full. I'm not sure if that's normal or not. I've also tried seeing how open the vent is on tank and seeing if that had any effect

 

[flyingscott]

Take the carb apart and clean it. Get a good rebuild kit that has the fuel pump and primer assemblies.