1988 mariner 115 hp help

[bigricky5]

Hey everyone new to this forum. Have a 1988 merc mariner 115hp. Ok. This engine has been giving me some issues. First off wouldnt idle in the water but on muffs idled fine. So I just adjusted the throttle links to the top carb so the carb plates would be cracked alittle open causing it to idle around 1700 out of water but when in water was around 900 to 1000. I know not the proper way to adjust idle but had to make work with what I had and the situation. Put about five or.six hours running no problem throught all rpm range no problems. Was going to look into adjusting timing and fixing the idle properly, but in water on that day while the engine was cold it wouldnt even reach over 3000 rpm, no power or torque to.plane. just plowed water. After about five minutes u could hear and feel possibly rest of the cylinders starting to fire surge with power for a split second off and on. Then bam all power again running all day long no problem. This has occurred twice now. Hoping someone has had similar issue. Have not checked anything yet. But while it was running like crap I would squeeze primer bulb no change bulb stays firm. Also pushed choked to see if it wakes up. But it just chked out and died. Someone please help. Not to familiar with the engine. But do.have experience in automotive field knowing how to use ohm/vol reader and what not.and I dont have a manual for this engine which I should I know and probably wouldnt be here.