2-stroke Nissan running away

[Ben16737]

Hi all,
Getting ready to sail for the first time in a few years. Among all the other repairs & jobs I’m doing, I got my ‘87 5 horse Nissan out of the garage to test it. I stored it correctly 3 or 4 years ago (flushed it, lubed everything, etc) so I figured if anything was wrong I might have a little trouble starting... Nope, opposite problem. It started right up, idled fine with the choke, but when I opened the choke the RPMs took off. Turning throttle all the way down had no effect. I was able to shut it down with the kill switch but it was dicey for a few seconds there.

It’s definitely running lean for some reason. I think the easy answer is give the carb a thorough cleaning in the hopes that something is just gummed up from sitting a couple years, meaning I’m not getting enough fuel flow. But if that doesn’t help, where should I look next?

Any advice appreciated!

 

[MikeHoncho]

Thats not a run-away. that is a screwed up carb. Gasoline engines cant run-away.

 

[kloudie1]

I think you have the diagnosis correct, the engine is "running away" (2 stroke racing to higher RPM with throttle closed) because of too lean a mixture.. The carburetor is a prime suspect but also check all fuel connections prior to the carb and check the carb base is tight to the reed plate and air is not leaking in there..

 

[Ben16737]

Hey all, just a quick follow up on this one. I finally got around to working with this some more, and it turns out some carb cleaner was all it needed. I soaked it good, let it sit for a while, and things fired up as they should. Idled normally.

Appreciate the responses!