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1999 20hp Mercury wont idle

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Ricky1953

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Motor is SN OG807291. This was my fathers motor that had not been started in over 10 years. MOTOR HAD NO SPARK< SO I replaced the stator, switchbox and trigger. Motor now has fire. Removed and cleaned carb and replaced all gaskets. Carb is getting fuel, but the motor will not idle. It will fire but not run. Looking for some ideas.
 
I serviced the complete carb, soaked it in a gallon can of carb cleaner for two days. The low speed jet is set at 1-1/4 turns from lightly seated. I checked the primer before reinstalling it on the engine as well as the float needle seat t make sure it was working. I can get it to run rough I hold the throttle open partly.
 
Ricky1953 said:
I serviced the complete carb, soaked it in a gallon can of carb cleaner for two days. The low speed jet is set at 1-1/4 turns from lightly seated. I checked the primer before reinstalling it on the engine as well as the float needle seat t make sure it was working. I can get it to run rough I hold the throttle open partly.
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Try opening the low speed needle more. did you put the carb base gasket on correctly? Did you use the correct one?
 
The carb gasket that came with the kit was different than the one already on there. I checked to make sure that the holes in the gasket lined up correctly and even went to the trouble to remove the carb and try the old gasket with the same results. I will try to open the low speed jet some more, but I don't think it will make a difference. I am going to check the compression tomorrow and recheck all the electrical that I changed out. The old stator was the "red" kind and the new one was a different one that was supposed to be a replacement.
 
The other one wasn't even close. I just don't know what to try next. I will open the low speed jet and I am going to check compression.
 
Check to make sure no water is entering the cylinders. Those motors like to leak through the exhaust plate. Did you replace the waterpump.
 
I checked the compression and it was 110 on both cylinders. There was no indication of water in the cylinders anywhere. I opened the low speed jet another 1/2 turn and there was no change. It must be a fuel issue because the plugs will spark across a one inch gap. I'm going to take the carb off again and start over.
 
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