Motor not holding fuel

I have a 1988 20hp merc that will not get up and go the bulb get hard after about 5 pumps and then it starts to loose pressure and go soft it's a brand new line with bulb the fitting on the tank is also new tank isn't I put a fuel filter in because there wasn't one before and I notice when I prime the bulb it get hard fuel will slowly go bac down into the tank I've taken the carb off twice cleaned once along with fuel filter then the second time I replaced all the gaskets there is no leaks I can see in any lines that gas is escaping or air coming in. The motor starts right up and at wot it only goes about 5mph will not plain off and I have to keep pumping the primer or it does out. I have gotten the raft to plain off and go about 3 times but only for a couple seconds randomly then motor shuts off again it barely ever happens. HELP

Re: Motor not holding fuel

just stating the obvious but check your gasket for the carb itself. there are vacuum ports in the gasket and if you put the gasket on backwards it will block those ports....

Re: Motor not holding fuel

Did you rebuild the fuel pump also??

Re: Motor not holding fuel

Mi duckdown said:

Did you rebuild the fuel pump also??

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The only rebuild kit kit the fuel pump I seen was the gasket kit I put on it I cut the ends off an old hose last night and went directly from the carb to the tank and same thing pumped the bulb and gas drain back into the tank the hose was kind of old and has a small leak i don't know if effects it though