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2009 mercury 50 hp idling problems

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Sommy

New member
Hi I was just wondering I’ve currently got a 50 hp merc 2 stroke oil injected which has some idling problems, on the go when cruising or WOT it runs fine but whenever brought down to 3 knots or lower it starts running rough and engine cuts out, also when cold takes a bit to get going and when started engine sometime cuts out as well, Was just wondering if anyone has any idea of what it might be and how to diagnose the problem
Cheers
 
Sommy said:
Hi I was just wondering I’ve currently got a 50 hp merc 2 stroke oil injected which has some idling problems, on the go when cruising or WOT it runs fine but whenever brought down to 3 knots or lower it starts running rough and engine cuts out, also when cold takes a bit to get going and when started engine sometime cuts out as well, Was just wondering if anyone has any idea of what it might be and how to diagnose the problem
Cheers
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I'm 73 years old and have seen a bit of transition with outboard systems. If this is a carbureted engine I would tell you to run some carb cleaner through it because in this age of ethanol based fuels water can clog a idle system where flow is not as brisk. Check fuel filter and gas tank for water.
Dry gas which is predominantly isopropanol will pick up the water, but don't run the engine with the Dry gas because I am not sure how isopropanol behave in a two cycle engine. After the circuit is free of water reset the idle mixture and you are good to go.
 
Running fine at WOT, but poor idle and trouble starting is usually caused by an issue with idle circuit in carbs. I've attached a diagram of our carbs. You'll need to remove carbs and take off the top cover #10 and clean out the small passages under that cover. Also,take out the adjustment screw #7 and clean that out also. Forced air and maybe a small wire works well. Carb cleaner with the "straw" attached is good too.
 
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