4 HP 4 stroke Mercury Tohatsu Nissan 2001

w2much

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Jun 22, 2005
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My newest Merc is built in Japan so I thought I would post here rather than the Mercury forum. I have acquired a 4 HP 4 stroke Merc 0R02206 . I recently finished off a Nissan 6 HP 4 stroke thanks to the help I received on this forum. With the 4 HP I am having the exact same issue as the 6 HP. Bad carburetor. On the 6 HP the pilot jet and the main nozzle were frozen in place. I could not remove them as they were already damaged from previous owner trying to extract them. With the forums help I was directed to a new carb model for the motor. It was reasonably priced. I purchased it and installed it. End of problem 6 HP ran and still runs great.

Now the 4HP. Exact same issue.The main nozzle is damaged again from the previous owner(s?). I was able to extract the pilot jet. I now have two bad carbs.This time I am not so eager to purchase a new carb. But if I do which one is recommended. If I am not mistaken a 4,5,or 6 HP carb will fit.Am I correct? If so which is recommended. The Mercs are higher priced and the same exact carbs as on the Nissans and the Tohatsus. There are quite a few different carbs which will fit this motor. Should I put on a 6 HP carb ?If I do purchase a new carb I prefer the least expensive one available.
Is it a common problem with these carbs that the nozzles and jets freeze in. I have soaked and heated them and when hope is lost tried soaking heating then vice grips to try to remove them? I am thinking of trying to drill them out next. If it does not work then I will go the new carb route as a last resort.

I was able to remove the pilot jet on the 4 HP. Does it breath to the outside of the carb body? I can not run anything through it so it is either severely clogged or there is not an air passageway to the outside.

Thanks for any sugesstions.I appreciate them
 

pvanv

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Apr 20, 2008
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3R4032001MCARBURETOR ASSY, MFS/NSF6A2$122.35

Available from any Tohatsu dealer. The idle jet is an air bleed, and has several tiny holes in it. Like any carb, if the aluminum corrodes, the jets will stick in place.
 

w2much

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At the point where the jets or nozzle can only be drilled out if removed at all is it worth it?
 

w2much

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one last effort before purchasing a new carb. I found an older 5 HP Honda carb that fits . I will try to clean it out and post the results. I see a 3r1 3200 carb on ebay will that carb work?
 

pvanv

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Apr 20, 2008
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3R1032001M is a carb for a 5A2, so if that is what is for sale, it will fit. Is that particular carb any good? That I can't answer.
 

w2much

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Jun 22, 2005
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A 6HP with a built in fuel tank. Best of both worlds. Thank you for your help
 
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