2stroke outboard crankcase check valves...

MystyBlue2

Well-Known Member
Joined
27 Aug 2020
Messages
819
Visit site
I have been scrolling through my owners manual and i have noticed there is 2 checkvalves on the reed housing, Top and bottom with a small vaccum hose connecting them both together,

Could someone please enlighten me on what the purpose of these are and what can happen if these fail and what failing symptoms are?

A little search on google and they seem to be common for causing trouble but no insight of symptoms or problems caused by a failure.

Could a failing check valve just cause rough running or could it end up being catastrophic?

My motor is fine, I'm just trying to increase my knowledge and just want to know what to look out for.

Cheers (y)
 
Try searching on "Mercury Bleed Hose".

Copied from another website:

"The hose sucks excess oil from the pooled oiled in the reed cage area where it may tend to pool & re-directs it to where it will be used/burned."

If it fails:

"... it's possible the motor may have a tendency to foul spark plugs & run a little rough / bad idle."
 
Last edited:
Try searching on "Mercury Bleed Hose".

Copied from another website:

"The hose sucks excess oil from the pooled oiled in the reed cage area where it may tend to pool & re-directs it to where it will be used/burned."

If it fails:

"... it's possible the motor may have a tendency to foul spark plugs & run a little rough / bad idle."
Thank you very much for that info. Good to know it wont be catastrophic. Every day is a school day eh (y)
 
Top