My earlier post:
One engine died running at 3000 rpm. Died like turning off a switch. Happened 3 times in one day, would not restart on 3rd time. No misfires, backfire, etc. Fault codes 42 & 42...... all electrical components were verified good by "swap" method, including the kill switch. All wiring & voltages tested good per Mercruiser tech manual. Verified distributor rotation when engine was cranked. NO spark, would not start. Mercruiser mechanic was working on this......

Last night we pulled the distributor & the drive gear is nearly GONE !! I have never seen a gear wear like this. Arizona Speed & Marine said GM had some bad gears made & to replace the gear with a "plated" one from GM, not Mercruiser. From the metal that has to be in the pan, I should do a tear down, but would lose most of the summer. I will install a new BRONZE gear, & maybe the cam gear is not too bad. At least the bronze will not destroy the bearings like steel does. Now to flush, flush, flush !!

That really sucks! I hope you can make it through with the new gear. Happy flushing and break out the magnets.

I doubt if a bronze gear will last more than 5 hours if the cam is set up for a cast gear.

Bronze gear isn't the answer. The gear will wear out rather guickly. Believe me, I've been there.

You have to find out the problem and get it corrected.

If you insist on running a Bronze gear you better take a couple with you so you can change them out in the water. They wear VERY rapidly.

BlownFormula,

There was another post with this same problem not too long ago. I don't remember what the fix was. I too would not be too quick to run that bronze gear. Is it possible that the cam is walking back and forth under load causing this premature failure? Is the motor stock? I personally have never taken apart 1 of these newer Merc roller motors, does amyone know what they use for a cam button? If that is bad, you will certainly burn up whatever kind of gear you put in it.

Checkmate 454 no cam button they use a thrust plate that bolts to the block.Heard that high volume/high pressure oil pump and a heavy weight oil can stress dis.gear.

The engine is stock '97 Mercruiser 454 Mag EFI with only 140 hours on it. I am changing to the bronze gears mostly to determine IF there was damage to the cam gear. If it is damaged only slightly, then maybe with a little care, I can make it until fall before I have to pull the engines. If no damage is evident, then I may install the plated gears by GM. This could really be a major problem, I just bought the boat & haven't even changed the title yet!! It would not make the wife happy to lose a season because of engines now.
I will have to see what the wear looks like after this weekend. Cross your finger.....mine will be !!

Since it is a known problem with Merc maybe Merc will handle fixing it. Could be worth a try.

Tom

My Mercruiser dealer/mechanic talked to the Mercury tech line. Mercruiser does not admit there is a GM or Mercruiser problem or a "known defect". That is even if a hundred or so OSO members have had the same problem. Ahhh, the power of Mr. Black to disavow a known problem.......why, we never heard about that!! We would have know if there was a problem.......yeh, right !