[blbj]

Hi everybodybought a 1980 80hp mercury outboard motorwater pump had gone out but had been replaced before I bought it, was told engine got hot and top cylinder was low on compression but said it ran good but wouldn't idle and had to baby it up to full rpms or it would kill.ran motor on the water, would die if idled to long, die if you gave it to much throttle to fast, would clear out and go 40mph. replaced top piston and new rings on all cylinders, disassemble/cleaned carbs. still die at idle, die if given to much throttle, still got 40mph after motor got going.went to adjust idle screw and saw gas coming out of lower carb. adjusted float, now it idles great. still dies if given to much throttle at one time. pumped gas bulb, sprayed wd40 in carb intake when giving throttle, no change.down to either to much gas or the timing is off. does anyone know what the timing is for a 1980 80 hp merc 4 cyclinder withthe thunderbolt ignition or have any other ideas?thanks in advance

[jstooks1]

hAD THE SAME PROBLEM WITH MY EVINRUDE, Did you try cleaning out the high speed jets. They should have a slot on them so you can unscrew them and clean out with a wire. Also check the connection on your choke(electrical) . Heat and corrosion can play hell on wires, they could be faulty and just hanging on by the insulation.Hope this helped

[blbj]

I had both carb fully disassembled and cleaned all the ports, doesn't mean I missed one. I had ruled out plugged ports because I had sprayed wd40 into the carb while it was running rough and it did not change the symptoms. the choke appeared to be operating normally and not sticking, you can hear the click when you restart the engine after it stalls.won't hurt to check it again though.thanks

[Rex]

IF IT STOPS AFTER IT IDLE FOR A LITTLE BITI WOULD SAY YOU GOT SOMETHING WITHTHE WIREING GOING BAD AFTER IT GET HOTIT START TO QUIT ON YOU.DOES IT RUN GOOD WHEN COLD?

[crazyray2]

on your engine think you either have an over lean misture that causes mixture to really lean out when you first open throttles or that timming is in fact off....think it should be 2-4 degrees but should have sticker on face plate of engine stating this.......where are your idle mixtures set at now?....think 1 1/2 turns out is start point then try it......if same problem back em out another 1/4 turn and try that.......also might do a search some time back someone posted about bleed tubes in a mercury causing your proble might be that......happy waters\