1980 7.5 Merc with Tillotson Won't stay Running, Puking Fuel from Vent

[Somerowl]

Good day all,
Splashed my 80 Mariner yesterday for the first time and after a hard time getting it started, she picked right up and was flying along.........then sputtered and died. Took another long time to get started again, but did so and it stalled upon down throttling at our destination. Was a real bear to get going and would only come up to about 1/4power for most of the 30 min ride back, but at times hit great speed and then back down to 1/4 power.
Bought gasket kit, tore it apart and noticed the description called out for a spring around the float valve, but mine didn't have that. Rebuilt it the best I could with the gaskets on hand (there were two old gaskets under the idle jet) and the fuel pump screen was bent back a bit letting some gunk in I'm sure. Put it back together and the fuel is still puking out the front atmospheric vent telling me the bowl is getting over filled.
I saw another archive post with the same issue that apparently cleared up with just getting the spring and new float valve which is all well and good, but I'm worried the fuel pump could be an issue as well. How can I test the fuel pump by itself or should I just fix the bowl and try it?
She's gotta be bullet proof for the next trip out with the wife so I can justify putting more money into the boating lifestyle (have a 61 Larson Glass project too).

Any advice / direction greatly appreciated.
:facepalm:

 

[Scott Danforth]

you should always replace the float when rebuilding a carb. specially one that is 35 years old.

get a new float, needle, and seat.

then take the prop off, put the lower in a 5 gallon bucket with a hose in it, and run it at home, if you no longer leak, then heat to the water for a sea trial.

 

[Somerowl]

Thanks Scott,
Already had the 5 gal bucket trick, that's a great one! I will replace everything I can on this unit if I can find it all. It ran for a bit at WOT and I was impressed with the little beastie pushing my 16' aluminum tank along. Appreciate the advice, will follow and post results.
:joyous:

 

[Somerowl]

So after a very frustrating back and forth with tillotson about the carburetor, I had to just take a shot at guessing what carbon it was. Turns out the needle valve was incorrect and sticking in the seat. Pump changed, new needle valve installed and she's running well! Thanks to everyone for helping!!