Re: 90hp 2-stroke mercury or johnson
The rough idle is a real sticking point to most of the customers. Merc tried adjusting one carb lean on the idle circuit like two on the 4-cylinder models, but without the accelerator pump they dog and die out of the hole. The midrange quirks of the 4-cylinder aren't problematic in the triples, but the idle on the 4's is decent and on the triples it's just plain awful. They're a constant challenge to adjust and if you go lake hopping, they're likely to run completely differently if the elevation is significantly different. In other words, the fine tuning is just about as operator intensive as old 40's and 50's outboards. You just don't have the knobs right out there in front so you can easily get at them. If you're on the same lake all the time, that's not a biggie. And if you adjust all three idles the same it's no biggie, jou just have to put up with the rough idle. But try to adjust that one carb lean enough to not fire and still have good accerelation is all but impossible on trailered boats that go from lake to lake.