Yam T9.9 cylinder head cover bolts torque

voileux

Recruit
Joined
Sep 28, 2010
Messages
3
Hi, I own an T9.9 2006 outboard on which I do the maintenance.

The outboard have a very small oil leak ( not noticeable drop on the dip stick after 60hr ). I am suspecting a leaky head cover's.

I like to re-torque the head cover, but my service manual does not give any torque for the 4 bolts.

Q1 Any guideline from experienced users?

Q2 Shall I take the opportunity to adjust the valve ( total run time 300hr ) and change the head cover gasket?

Thanks
Andre
 

voileux

Recruit
Joined
Sep 28, 2010
Messages
3
Re: Yam T9.9 cylinder head cover bolts torque

Sorry I found the torque value ( as well as sequence ) casted on the cover.

However the oil leak is still a mystery!

Andre
 

rodbolt

Supreme Mariner
Joined
Sep 1, 2003
Messages
20,066
Re: Yam T9.9 cylinder head cover bolts torque

I doubt the cover was leaking, most likly normal blowby gasses under the cowl.
did not have the manual at the house but I imagine the torque to be about 8ft pounds.
not critical at all and I imagine I would not bother torqueing them.
however I do have 30 years experience with small fasteners.
its a cover, not a cyl head or a rod bolt or a crankcase bolt, its simply a cover.
biggest thing is DO NOT wring it off.
 

voileux

Recruit
Joined
Sep 28, 2010
Messages
3
Re: Yam T9.9 cylinder head cover bolts torque

Thanks rodbolt.

I may be too ambitious but I hates to drop, even a single drop, oil based product in the lake. However, few table spoon a season does not compare to what my previous 2 stroke outboard was doing.

Regards
Andre
 

rodbolt

Supreme Mariner
Joined
Sep 1, 2003
Messages
20,066
Re: Yam T9.9 cylinder head cover bolts torque

your going to get a certain amount of condensed blowby gasses in the airbox that will drip some and work its way around the engine.
 
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