I was out again this weekend. After installing ground cable to starter I still have the same problem. I am 100% sure it is the timing causing my problem.
Started fine when unloading off the trailer. 10 min ride to the beach. Shut it off. Tried to restart it. The starter engaged/motor started to turn slow and then I new it was just going to start grinding.

Couple hrs later I loosened starter and re-tightened it. An hr later went to start and it turned over slow again.

I loosened up the distributor and retarded the timing slightly. It turned over fine and started.
It started fine half a dozen times with the timing turned down.

bajabob had a solution for this, but I am wondering if I was to get a brand new started, not rebuild, would this possibly work.
I am thinking that my rebuilt starter may be alittle weak even though some components have been replaced.

http://stores.ebay.com/DB-Electrical...=p4634.c0.m322 call this place you get a brand new starter whole sale i did works great. msd has what you want starterbox mine work great easy to hook up

I feel your pain is all it takes is one buck and off with the nose.
this one made it three weeks

Are you certain your solenoids are de-energizing or being de-energized, and opening the circuit?

Me or him lol me it never started ,,,timing locked at 32 cold start and it bucked (632 tall deck 10;1) the little stock starters just dont hold up,the CSI on the starboard is holding up,knok on wood.
Getting a tilton super for the port in the morning

Look at the starter bolts again, a bolt that is too long will cause this problem.

bajabob had a solution for this, but I am wondering if I was to get a brand new started, not rebuild, would this possibly work.
I am thinking that my rebuilt starter may be alittle weak even though some components have been replaced.[/QUOTE]

I have also problem with one 454, loose starting new solenoid.
I replace whole starter, no starter problems anymoore.

buy new one and is failure still go on, you can be sure the
problem is somewhere else..

Talked with a couple mechanics this week.
Stated: Mercruiser does not recommend running new motor timing more than 8 degrees at idle (28-30TTDC) until the motor loosens up some (approx. 20hrs depending how hard you break it in).

When the motor is cold it will start fine, but once it heats up to running temps, everything expands (bearings, rings etc.)
This does work for me so I will run it here for awhile and turn it back up in the future.
Or I can by a new starter that might work or it might not.

What is your initial timing set at ?
Do you still have the Thunderbolt Dist or do you have something else installed ?

There are a couple of things that will do that to the drive end housing.
One, kick back against timing
Two, incorrect drive gear to flywheel tooth depth ( shimming)
Three, too long a bolt ( loose starter moves)
Four, wrong housing ( Imperial 3/8 holes and 10mm bolts)

If you are not running the timing locked at full advance, I suspect your dealing with issue number two.

When everything heats up, particularilty after a hot soak, the teeth grow, the housing grows, the ring gear grows and IF you did have any clearance on a cold motor, it is now gone and the flywheel will wipe out drive end housings one after the other.

The gears crush together with no space between the teeth. This causes hard engagement ( grind when key turned) and once the engine fires, the initial force of the flywheel against the starter drive literally pushes the drive sideways away from the flywheel and breaks the drive end housing.

Use liquid paper to paint the drive teeth completely. Install the starter using one shim. Crank the motor a few times and then pull the starter and inspect the wera pattern on the drive. If the liquid paper has been removed right down to the bottom of the teeth, add another shim and retest.