1989 merc alpha one 4.3 mech. fuel pump issue?

[unclebb]

boat fires up in the yard, in the water i have to crank n give throttle, runs good for an hour, buddy said ,fuel pump, i took it apart, it was loaded up with gunk, bad, 1/4" line going to carb was plugged nipple on carb plugged, i cleaned everything put new fuel line on to carb, took it out, same deal ran great for over an hour the cuts out , misses, backfires, swam for an hour, boat ran great for half hour,the diaphram in the fuel pump is crusty from age,1989, no fuel filter, so im thinking new fuel pump?but, why would it run good for a bit? im thinkin if its bad it should fail on and off always, not after an hour?? buddy says put a electronical one on it n do away with the mechanical one,mech one at the marina 285$ autopart store ordering it 180$ e bay 59? or get a electronical one at auto parts store for a 4.3 50$ some. or, am i barking up the wrong tree all together?? thanks, sorry it took me 20 mins to figure out how to post and i hope i did it in the right forum??

 

[Bt Doctur]

you need to figure out what the problem is first, then buy the correct parts.Fuel pumps are NOT that expensive.
This could be something as simple as a anti-syphon valve or just some crud in the gas tank that your shaking loose

 

[unclebb]

Ok thank you.I'm gonna buy a new fuel pump since it's 30 yrs old n jacked up.put a fuel filter before it.since I don't have one,and since my fuel pump was so correded up I'm sure that crud came from the tank,then see what happens,ain't out nutn.needs replaced anyways,I should drain the gas tank,it sat almost 2 years,I told boat mech. Down the street to drain it when he had it,he didnt, it had 3/8 of a tank,I filled it up with 93 oct. Then 89, then 93, I did put seafoam in it when it was down then again this early summer,2 year old ethanol prob won't light with a match.lol.should be all out by now, but maybe not,its just wierd,runs killer for an hour plus,then acts up,sit an hour,runs killer for 35mins.as a shade tree mechanic It sure sounds and acts like a fuel problem.new plugs,new wires,new cap and rotor,fresh oil change,I can't find a water separator on it,question: is a inline fuel filter for my size of line from autozone good enough?