starter motors keep breaking

[renny1]

3 litre 1999 140hp mercruiser
as we know i have just had a reconditioned engine installed which runs beautiful and purrs nice BUT i am now buying my 3rd starter motor in as many weeks,what happens is the starter turns the engine but now and again there is a big bang kind of noise like the flywheel just stops dead or trys to run backwards,the first starter the hole which the bolt goes through (on the starter) broke so i purchased another thinking its because i got a cheap one on ebay,so the 2nd i went to a chandlery and paid full price this worked fine for a week or so until i went to start it and bang same noise.
i then opened the starter up and the plastic gear in the starter was all threaded.i have been told its the timing
is this a timing issue even though engine is running fine???

 

[Bondo]

Re: starter motors keep breaking

Ayuh,... I'd guess Hydro-lock, or possibly bad timing...

 

[Silvertip]

Re: starter motors keep breaking

Does the starter have a bracket that ties the front end to the engine block? If not, fabricate one to relieve some of the torsional stresses. Also make sure the bolts are the proper style. Starter mounting bolts have a knurled area just beneath the head. Standard bolts will not work in that application as they would allow the starter to shift slightly. An incorrect or damaged flywheel or incorrect starter can also cause the problem due to improper tooth meshing. But by all means, check ignition timing as engine "kick back" can do this as can hydrolocking.

 

[intrepidvoyager]

Re: starter motors keep breaking

had this issue before on a 3.0 .... these engines do not like aftermarket starters ...even a Wilson which is a good starter did not last more than a week in a 3.0 VP ..... so to start with make sure you use the original manufactures, think you said Merc, starter with the extra bracket and use locktite blue on NEW oem starter bolts.

when you instal the starter make sure there is no crud on the mating surface on the block .... as it is upside down get in there with a mirror and good light ,,also where the starter drive goes into the bellhousing ..

 

[TilliamWe]

Re: starter motors keep breaking

Ayuh,... I'd guess Hydro-lock, or possibly bad timing...

I agree with this totally.

 

[renny1]

Re: starter motors keep breaking

thanks guys the timing was set to 12 btdc

 

[intrepidvoyager]

Re: starter motors keep breaking

hi ..........so guess the conclusion was that despite the fact the engine was running fine ..unlikely possible at 12 degrees BTDC ..... all of a sudden the starter destructs .....was your distributor loose ....I can see where a high pre TDC ignition could push the crank backwards but if the timing was that bad how would the engine run fine. I am always curious about these types of situations in case I run into them in the future, so would appreciate if you post if another starter destructs.. thanks

 

[Bt Doctur]

Re: starter motors keep breaking

Supposed to be closer to 0-2 .Advanced timing will blow the head gasket on the 3.0