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Johnson 40 idle fix

smoody

New member
"Can someone help me with this

"Can someone help me with this. I have a 2000 40HP Johnson, the thing idles fine on the hose but when put in the water it will stall out. It will fire back up easily. It will stay running as long as I keep the carbs open a bit. I know the water puts back pressure on the engine but could this just be that the engine idle speed is set to low? I look at Seloc online and it shows how to adjust the idle, but it doesn't say which way to adjust the screw for increase/decrease. Also where do I hook a shop tach up to it? OR is there something else causing the idle issue? the bulb stays hard, has a new fuel pump. At WOT it doesnt skip a beat.

Thanks"
 
"What are the compression read

"What are the compression readings of all cylinders?

With the spark plugs removed, the spark should jump a 7/16" gap with a strong blue lightning like flame.... a real SNAP! Does it?

Are you running the recommended s/plugs, gap?

If the above are as they should be, I would assume that the carburetors is somewhat fouled, in which case, remove, clean, and rebuild them.

Advancing the throttle/idle is simply a matter of adjusting the threaded trunion on the throttle cable..... in which direction should be obvious."
 
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