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Nissan4hp starting/idle problem

W

Wilf

New member
Have an issue with my 4hp outboard , a few weeks ago I was out on the dingy and had to slow right down to idle and it cut out and wouldn’t start again but started about an hour later,this happened a few times, so since then I have changed the fuel filter, spark plug, took the carb out and cleaned it, tried it again in the garage starts with full choke and then runs great.

put it back on the boat but same problem, cuts out if idle is too low and won’t start again, I read another post about fuel getting into the oil and thought the dipstick had a smell of gas so I replaced the fuel pump I’ve also installed an external tank since then so it had less chance of running out of gas. But same problem , thought about buying a new carb but don’t know if a new carb needs adjusted or not? Any advice would be appreciated thanks
 
What is your model? What method did you use to clean the carb? Do you always eityher idle the carb dry at the end of the day, or drain it? What is your idle RPM?
 
pvanv said:
What is your model? What method did you use to clean the carb? Do you always eityher idle the carb dry at the end of the day, or drain it? What is your idle RPM?
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It’s a Nsf4a I usually run it dry after using it , I took the carb apart and jets and soaked them for about 8 hours don’t know my idle rpm it started and ran ok after cleaning it but if I go too slow it cuts out and won’t start again unless I leave it a few hours
 
Hey Paul, The product I soaked it in was recommended by the marine store can’t remember which product it was, I sprayed jets too, what does it mean if the plug was wet or if it is dry? I will check it later I was considering getting a new carb or even an upgraded 4hp to 6 hp but don’t know if it was all ready upgraded as it has a metal prop
 
pvanv said:
What did you soak it in? When it won't start, is the plug wet or dry?
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Can’t remember what I soaked it in it was recommended by the marine store, I prayed the jets too, I will check the plug later Iwhat does it mean if it’s wet or if itsdry
 
Wet means gas and no spark; dry means no gas.

Did you completely disassemble the carb -- including emulsion tube nozzle -- and after soaking, thoroughly blow out each and every passage with generic carb spray?

6 hp carb will be stamped 3R4. 4 hp carb will be stamped 3H9.
 
pvanv said:
Wet means gas and no spark; dry means no gas.

Did you completely disassemble the carb -- including emulsion tube nozzle -- and after soaking, thoroughly blow out each and every passage with generic carb spray?

6 hp carb will be stamped 3R4. 4 hp carb will be stamped 3H9.
Click to expand...
Yes I disassembled it and took out jets and blew them out with the spray, I put it all back together it stated and ran great but when I came back to the dock and slowed it right down it cut out and wouldn’t start again took it home and tried it next day with full choke, started right up again I’m going to start it when I get home and let it stall and try it again then I will check the plug and let you know, thanks for your help so far
 
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