How to set carburator idle jets on 115 mec 2 stroke

[killerpirate]

Hello, i own a 4 cyl 115 merc 2 stroke and it idles quite high. I want to check if the idle screw on the top two carbs are right, but i cant find any info on the position of the idle screw. I know the position it is on right now (as i bought it), but im scared that if i set it in the wrong position the engine will run lean (or rich) and do damage. Can i just keep turning them until i find the engine running good?
Also, does changing the idle jet affect higher rpm range? My guess is no, since the fuel is then going trough the main jet, right?
Im not a carb specialist, all butterfly valves are closes at idle.

[Merc 2.5]

Not familar with those carbs , but best to to have is a manual , u wont hurt the motor messin with idle screw

[killerpirate]

Thanks for your reply, i cant really find that info on the manual, i actually cant really find the right manual. I got the 2 piece cowling that flips sideways

[RSWORDS]

God I hate to do it.... lol

Serial number?

Oh and it will idle high on the hose

[Merc 2.5]

God I hate to do it.... lol

Serial number?

Oh and it will only high on the hose

Hahaha. Hey sumtimes its neccessary,

[Dave Strong]

1 1/4 turns out from lightly seated is base setting, only adjust in the water boat floating at normal resting height.

Dave

[FMP]

Motor at normal operating temperature, in gear no throttle just trolling approach to dock speed. Tied to dock, normal pitch prop. Then if it's very cold outside 30-40°F a little richer than summer. From where it idles at the noticeable highest rpm and not sneezing lean with the setting give it another 1/8 turn out, rich. All the carbs should be near the same setting but dial the same adjust one after another in small increments.That should get you close if your base ign advance is set correctly. You need a proper manual.
Also is that one of those 2+2 motors that use two cylinders at idle in certain situations? Maybe that's the 125.

Maybe download it if you can't find factory

http://www.selocmarine.com/engines/Mercury.php

[Dave S]

They ruun on the top 2 clys…...you just adjust the timeing till it gets low and gets on the idle circuit and almost stalls. But first get the slash mark on the throttle cam lined up with carb roller. Adjust small 5/16 bolt /or plastic covered screw just above the 9/16 bolt that is the pivot point.

[killerpirate]

God I hate to do it.... lol

Serial number?

Oh and it will idle high on the hose

Its not just on the hose, also in the water, sometimes around 1700rpm, and after running (when engine is hot) sometimes 2500 RPM!

Serial numer is 0D176140

[killerpirate]

But if i set the timing lower, will the top end timing also drop? And if i just set the timing to low (and the problem is not the timing, but for example a vacuum leak) wont that result in a hot exhaust?

[killerpirate]

Correct, 2+2 engine. Thanks!

[RSWORDS]

There is a check valve in each the bottom 2 cyls that if it goes bad it will kinda somewhat run on that cyl and can cause high idle