Honda outboard 4-stroke 10 HP: noise at low speed with gear in
 

Hi! I have a problem with a strong noise appearing only at low speed
(roughly at one quarter of the maximum throttle) and it appears only
when the forward gear is inserted. The noise is like a 'rod shaking'
(kla-kla-kla type of noise) and it seems that it comes from the bottom
of
the engine, near the top of the trasmission shaft.
The noise tends to disappear when rpm increases.
It is like something has become loosen and touches alternatively at two
sides....
Anyone could tell me what I should check in the engine? I do have the
shop manual.

Many tanks!!

Domenico