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90 hp J90PLEEB idle issures I need advise

M

marvin1952

New member
This engine set for sometime. how long don't know I recently bought boat. Engine cranks ok but will knot idle very long goes dead. Also after pushing in the choke a few times and raising the trottle it will take off and run great. when you come back in after a prolong idle the engine will go dead and you have to start the process of cranking and fast idle all over. I have run 3 can of Seafoam and pulled the idle screws along with the bole drain screws and sprayed carb cleaner the idle jet holes and the midd range air orfices. I seamed to have cleared up and then it has stared again. Do I need to pull the carbs or do I have weak fuel delivery at low speed. I need advise

Mt
 
Fuel systems gum up if stored with fuel in them.---------When motor stops , what happens when you operate the manual fuel pump ( aka primer bulb ) does it pump fuel to indicate that the VRO pump is not working properly ?-------------Compression test results are ??---------Spark test results are ?----------might as well pull a carburetor apart to see if indeed there is varnish / gum deposits.--------Trouble shooting 101 for you.
 
When I pulled the drain screws from the carb boles there was sign of varnish, The first time I blew and washed out the idle screw jets I thought I had the problem fixed but it started again. If you choke it just when it starts to die it will pick up and after you do this for three or four times and advance the throttle it will pick up and run. After running down the lake and stop, idle for a short time it will take off again no problem. it is when you are idling into a boat launch area that it will start to die. The engine runs great otherwise. I have checked all fittings and find no air leak. I am capable of dismantling and cleaning the carbs but just did not want to if I had another Problem. What does the vapor pump and float do?
 
The engine will idle all day on a water hose, I have not checked the spark or compression. My take was that the engine cranks and runs great other than the aides problem. Turns 5200 rpm with a 19 pitch prop.
 
On a 2 stroke the carburetors are also the " oil pump " ------starving for fuel means starving for oil.-----------No point risking damaging your engine with iffy fuel system.---------But it is a choice , many folks just love to ignore advice.--------Trouble shooting is the way forward.
 
Tell me this. What function does the vapor pump serve. it has it,s own fuel bole and needle and seat. Could that cause a slow speed fuel starvation. I don,,t mind tearing into all of it I just want to figure out what all I need to rebuild while I am in there. Could the fuel pump it self be weak?
 
Could be the back pressure is lowering the rpm. set the rpm with the engine in the water. When you set the rpm on the hose there is no back pressure.
 
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