fuel problems? 78 merc 85hp

Would this problem affect the engine in open throttle and cause it to go slow? I have a problem with my 78 merc 85hp. The merc starts fine but when I put the throttle open it boggs out. I tool the boat in and the mechanic said the stator was bad so I replaced that. I told him to put it on the dyno and it got up to 5500rpms. I put the boat in the water and the boat has the same problem not going when throttle is opened. So I took the boat back and he didn't understand what was wrong. So I took him out on the water and showed him the problem. I opened up the boat and he took off the top case and the carb cover he stuck a screw driver in the bottom carb hole and it took off. Wow I was amazed my boat was going 5500 rpms. Then he took the screw driver out and it started slowing down back to bogging. He said the bottom seal(Lamberg seal?not sure it this is the right name of seal) on the lower crank is bad , thus causing the boat to suck air. And he said do a rebuild which would cost $2000. So I have the same problem my boat boggs out. Sometimes I press on the fuel bulb and the boat goes fast and I keep pressing it and the boat go faster. So I as so confused???????? WHat can I do to fix?I rebuilt carbs,new stator,.

Re: fuel problems? 78 merc 85hp

Did you end up rebuilding the power head, or replacing the seal (I have never heard of a Lamberg seal). It sounds to me like you are getting too much fuel. What was the old timer doing with the screw driver? What it in the carburator?

Re: fuel problems? 78 merc 85hp

at a loss.... how would stickin a screwdriver in carb fix a bad seal?<br />

Re: fuel problems? 78 merc 85hp

If pumping the primer bulb helps, it sounds like a fuel delivery problem (bad pump) or an air leak in a line or fitting. Not sure what 'seal' your mechanic was talking about.

Re: fuel problems? 78 merc 85hp

I too am having this problem. 1986 Mercury 90, just had 2 pistons replaced. If I bulb it a lot it will crank and run but then run out after a very short while. Piston job sounds good. I replace the bladder on the fuel pump, because the old looked really worn, and it still does the same thing. I am going to try replacing the line next.

Re: fuel problems? 78 merc 85hp

The mechanic came out on the boat and took the carb cover off and put his finger in the bottom carb hole when the motor was opened and went fast he took his finger out of the hole and it slow down until it died out. So how can i check my fuel line if it is bad or not? Someone said they can blow air threw the tube from the gas tank to see if it leaks. Sound right??

Re: fuel problems? 78 merc 85hp

Do you guys know of any good mercury mechanics in the oceanside area or close to it. Thanks

Re: fuel problems? 78 merc 85hp

captin 420 <br /><br />"I opened up the boat and he took off the top case and the carb cover he stuck a screw driver in the bottom carb hole and it took off."<br /><br />It sounds like the butterfly for the bottom carb is not opening. The only thing that I can think of that the mechanic would do with a screw driver that would produce that result is to nudge the butterfly open.<br /><br />On top of the bottom carb there is a screw that fastens the carb linkage rod to the bottom carb. Make sure it is tight. With the boat out of the water (not-running) move the throttle control to full speed and make sure all three carb butterflys are wide open. They should be straight in line with the carb bore so they will produce the least resistance to intake of air. Also all three butterflys should move in unison.<br /><br />Good luck,<br /><br />Gold Bear