There is a very specific procedure for correctly setting the timing on the TB V. It has to be placed in Base Mode You will need a copy of the Merc manual to get it right. Don may have a copy he can post.
Line up the 2 dots on the timing chain if your cover is off,or if its on align the tdc mark on the balancer,then install the distributor and make sure the rotor is pointing at the #1 spark plug wire.When you get it started hit it with a timing light and set it to spec.Just make sure its at TDC on the compression stroke.
There is a very specific procedure for correctly setting the timing on the TB V. It has to be placed in Base Mode You will need a copy of the Merc manual to get it right. Don may have a copy he can post.