496 MAG died, crank sensor?
 

I was cruising last night and the engine suddenly shut off as if the key was turned. Everything appears in order, no funny smells, fluids are all checked for level, etc. Breakers, fuses, etc look good. The engine will crank but will not attempt to fire.

I hear the fuel pump run, no issue there.

I could not get spark and noticed that the tach does not move while cranking. I am leaning towards the crank position sensor. The local marina has one so I am going to swap that out. He said he probably can't even get it on the scanner for about a week and a half or I would try that first.


Any other suggestions? Thanks in advance!

That sounds plausible. If you check for injector pulse and there is none, that would indicate a crank sensor too.

UPDATE


I was able to get the new crank position sensor installed. Fired right up! The search feature was my best friend for this one. Thanks!

Mine did the samething yesterday, will turn over
but no spark. Goes into shop monday.

save yourself some cash and do it yourself. The sensor was about $100. The biggest pain is getting to it but once you do there is only one bolt holding it in place. I used a long set of pliers to pull it out due to the sticking O ring. It's simple!

those motors are bullit proof as long as you dont
build them, first problem i had is this one and i
have over 700 hrs.

Had that happen to my 496 in the chevy truck. Dealer stumbled as it can be an intermittant problem too. They don't always just go out completley. Old super duty fords do this too.

Nice call!!

so my 496 really died...hydro locked. less than 400 hours. Ill know a little more on monday on how bad it is but someone said I should keep an eye out here for a used one. Anyone know of one available?

Cant get that lucky , computor went, one local
shop wants 1900.00 for new ,1200.00 for
merc rebuilt.