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Just replaced the thermostats and waterpump impeller, but now the motor is idling high (around 1200rpm). Anyone know how to adjust the idle on this particular motor? Any help would be greatly appreciated!
I would think there should be an idle adjustment screw on the throttle linkage somewhere! Doesn't make sense that after you replaced what you did that the idle is to high! Do these engines have a temp sensor, which allows them to run at a higher idle till warmed up?
If you're expecting normal idle on a hose, you won't get it. The back pressure of the water against the through hub exhaust is critical. They always idle higher out of the water.
Mud's right , I used to put my foot over the exhaust to hush it up a little, found out it idled better. 2 stroke exhaust is critical for good running. Look at all the motorcycle mufflers and differant power bands each muffler caters to.
The timing arm adjust the idle speed. It it's a carb motor, it has a ratchet deal over the flywheel cover. Any chance you moved the linkage getting the shift shaft loose? 1200 sounds too high to me, even on a hose.
1000 -1200 is just about where my 150 Johnson would idle on the trailer. Put the boat in the water or put the lower unit in a 55 gallon drum, check the idle and then adjust IF necessary.
Thanks guys, I haven't had a chance to put it in the water since, so hopefully I'll get to run it this weekend. I know it usually idles higher on the hose, but 1200 seems a little excessive. Weather down here last weekend was 84 degrees (Replaced springs on trailer, couldn't use boat) this weekend (Boat ready to go) weatherman calling for 50 degrees. Go figure!
1200 is not excessive. If you set your idle now it will not idle when you put it back in the water. Set aside 2 minutes next time you are out and you will have a perfectly idlng motor.
2000 Johnson 150 idle adjustment 
