Yamaha f9.9 timing belt change

[seanfoster]

Does anyone with one of these engines know how to change the timing belt?

I've been looking for a service manual but can't seem to find one (I have one which covers a large range of 4 stroke yam engines but nothing in it for changing belts).

Any help would be appreciated!

 

[mickywillis]

When we do car ones, there is a VERY easy way to do it (if you do not need to remove the flywheel/pulley on your engine)
Take out spark plugs and remove any cowlings /covers which stop fingers touching the belt.
With a Stanley knive, have an assistant turn the engine over by hand and cut the belt in half, around its total length.
Put the new belt onto the pulleys (you may have to use the assistant again to turn the engine over by hand)
Once the new belt is fed around all the new pulleys, simply cut away the remainder of the old belt and carry on turning engine over by hand, until the new belt is fully wrapped.
This method saves having to alter the belt tensioners and doesn't need to alter the timing or require the use of locks to hold the engine at set timing positions.

 

[VicS]

You dont say the year of your engine,
but you have looked at the
Seloc manual that covers 2 -250 hp 2and 4 strokes from '84 to '96
and the one that covers Yamaha, Mariner and Mercury 4 strokes 2.5 to 250hp, 1995 to 2004.
And the Clymer manual that covers 9.9 to 100hp from 1985 to 1999.

I'd doubt if its possible without removing the flywheel and magneto components as well but I see no mention of a tensioner in the parts lists I've looked at.

If you decide to have ago. Mark both crankshaft sprocket and camshaft sprocket so that you can be sure to keep then correctly timed unless the above procedure with a Stanley knife is applicable.

maybe worth asking on the iBoats forums and the MarineEngine forums

 

[seanfoster]

Thanks for the replies I think I will be able to change it using the stanley knife method!

The outboard is a 1990 Yamaha F9.9 AE