Nissan 3.5 2 stroke. Reed valve vs. LU gasket???

[beeraday]

Sup guys?
So here is my problem. I have a Nissan 3.5 forward gear only. It runs only if I have the choke pulled. As soon as I push it back in it dies. This motor is super clean with low hours on it. I happen to have two of these motors so just to check, I pulled the carb off the motor that works just fine. Same thing happens, only runs with choke pulled. This leads me to believe that either I have a leak in the lower unit seal or the reed valve may be damaged. My questions to you is what should I check first? Is there a test to see which one is the problem? Or should I start with the LU and work my way up. Just curious. Thanks for the help.

 

[Sea Rider]

Re: Nissan 3.5 2 stroke. Reed valve vs. LU gasket???

LU is the engine's propulsion & cooling system, nothing to do with gas problems, There's no LU gasket, there is a gasket between drive shaft gasket and cylinder crank case. Is small gas filter located inside fuel **** clean ?

Happy Boating

 

[TOHATSU GURU]

Re: Nissan 3.5 2 stroke. Reed valve vs. LU gasket???

Possibly low compression due to:

reed failure
bad seal on carb o-ring
blown head gasket
scored block
scored piston
stuck ring
blown base gasket
bad crank shaft seal
pissed off gremlin


Usually just a dirty carb though

 

[beeraday]

Re: Nissan 3.5 2 stroke. Reed valve vs. LU gasket???

Possibly low compression due to:

reed failure
bad seal on carb o-ring
blown head gasket
scored block
scored piston
stuck ring
blown base gasket
bad crank shaft seal
pissed off gremlin


Usually just a dirty carb though

Thanks for the reply. I know for sure that it is either a bad crank shaft seal or the reed. My question was.... Is there a way to detect which one it is with out having to open everything up?

Thanks

 

[TOHATSU GURU]

Re: Nissan 3.5 2 stroke. Reed valve vs. LU gasket???

Sort of. Put a piece of paper in front of the carb while it is running. If fuel is spitting out is may be the reed....It's almost never a reed.

 

[beeraday]

Re: Nissan 3.5 2 stroke. Reed valve vs. LU gasket???

Ok will do tomorrow and will post my results. I figured that with such a small house power engine it would more likely NOT be the reed. I just was looking for some sort of tell. Thanks GURU!!

 

[Sea Rider]

Re: Nissan 3.5 2 stroke. Reed valve vs. LU gasket???

Perform a compression test and take the nail out, anyway how old is the little devil ? If you have taken the carb out, there's a black rubber o'ring located inside carb's neck that seals against crank case, check to see if still there.

Happy Boating