What would be the first performance upgrade that would benefit with the least amount of money? (i.e. air filter, jets, exhaust, scoop grate etc.) Any suggestions would be great.
1986 Mercuiser 140 4-cyl, that has trouble starting. It acts as if the fourth cylinder doesn't fire until after a few minutes of warming up. The boat shakes moderate amounts during this period. There is also a little black smoke that happens during this time but again goes away once warm...
