I have a 1992 Mercury 150 black max that will not idle in neutral for more than a minute or two. If I put it in gear it will idle along at a little over 1000 rpm just fine and after I have been running at higher speeds I can put it in neutral and it idles fine for about five minutes and then it seems to start starving for fuel and knocks off. It is also difficult to get it cranked. It idles fine when it's in gear and runs fine at higher speeds. I read in the forums that the water pump impeller can cause this or trash in the fuel filter. Any ideas about things to check would be appreciated!
