I know this isn't the right section but I have already posted this in the right section but this gets more traffic. Ok, so I have a 1980 mercury 70 hp. When I pump the primer bulb it will not get solid as a rock. Still stays squishy but will not pump all the way. I would say hard but I have seen the viagra jokes blah blah blah lol. Anyways when I pump it if I keep pumping it the bottom carb starts leaking out of a little hole that is near the butterfly on the carb. I thought hey common sense you keep pumping the bulb it will flood the motor. So I ruled out the floats although a few people still think that is a problem. So I replaced the bulb and even replaced the fuel filter with a glass fuel filter from vatozone. Was told those are better since they are clear. If you start it and floor it, it will run for around 3secs but if someone primes it, it will run all day but only half throttle while its all the way to the floor. So next I took my fuel pump off and I'm not sure if the diaphragm was damaged while I took it off or this could be the issue. Would a diaphragm cause the bulb to not stay solid? Would a diaphragm cause the carb (just the bottome one) to flood out and leak? Please help I'm tweaking over here I need to fish! Lol

Sounds like the fuel line is sucking air in. I would try replacing the entire hose and primer bulb. I had an old thunderbolt that happen to. Plus it's an easy fix

I'd put money on a bad fuel pump diaphragm and/or plugged in-line fuel filter. See this: http://www.boats.net/parts/search/Merc2/Mercury/70%20%283%20CYL.%29/8042350%20THRU%208065064/FUEL%20PUMP%2C%20FUEL%20FILTER%20AND%20FUEL%20LINES/parts.html#

If this is the problem you can fix it yourself easily.

Good luck.

Fuel pump diaphram. Buy the kit and replace.

I'm gonna buy it tomorrow and give it a try. Thanks

Yep yep. You need to replace the fuel pump diaphragm. Might as well rebuild the carb while you have it off.

replace the line that jumps carb to carb

If it will run at all I would run Sea Foam through it first.

are the fuel lines black? or gray? is the lettering blue or red ? some lines aren't made to handle our cheap fuel we have these days we had the same kind of trouble a couple years ago, give up and changed the fuel lines at the lake, trouble gone also now that you have opened the pump my guess is you'll need to replace the diaphragm too

That old of a motor the Ethanol could have eaten the hose up. It is tough on motors and lines.

All it takes is a pin hole in the fuel line for this to happen. It can be small enough fuel won't even come out of it and still pull air. If the fuel pump or kit doesn't fix it replace the line. This comes from experience. I replaced an old line just because I was reworking the boat. The new line had a pin hole some where. Replaced it again and it ran great.

Where can you get fuel lines without going to a marine center. I was just gonna get around 5 ft of lines and just replace every dang fuel line there is. All my lines are black except the primer bulb line

Autozone

Ok found the problem. Definitely the diaphragm. She purrs like a baby lion now! Thanks you guys. Next is changing all the fuel lines for good measure.

Walmart may have Mercury lines.