Trouble with top end

[InTheHole]

I had an 87 merc with the exact same symptoms and after checking out everything that had to do with fuel I still had the problem. I took it to a mechanic and he found that 1 of the power pacs ( 2 in that engine) was cutting out at high speed. He replaced it and problem solved. I would still start with the fuel system - simple things first.

[macojoe]

Cloged Filter, Vents clear, ball not holding??

This new gas can cause filter clogs for the first few tanks, I had a problem like that last year. But if you have used a few tanks of it you should be fine.

[afterhours]

check for scamooge in carb bowls.

[zacs]

scamooge is a very technical term from gunk, right?

[afterhours]

gunk and/or debris- motor is 17 yo. would'nt hurt to clean 'em. had the very same problem with a newer motor.