Alpha One Mercruiser 3.0 no start

Trying to diagnose engine issue with engine that is used in fresh water only with out experiencing any issues for past three summers:

- engine started fine on this summer season's maiden voyage; ran it slow and easy for about 3 miles and then berthed it for the night.

- engine started fine next day and after warming it up, brought up to maximum speed for a couple of miles and then berthed it for a few minutes and turned engine off. Then started it up again and it stalled a couple of hundred yard off shore. Engine seemed to be turning over fine but would not catch. Also noticed that none of the gauges (temp, oil pressure, trim level, voltage, gas tank) were activating when key turned to on position nor while motor was being turned over. I believe this to be unusual and perhaps a clue to what might be going on. Bilge pump and blower turn on as usual though.

- boat was stored at the usual marina over the winter and was winterized and then set up for the summer season by them. 3/4 of the tank was filled with fresh fuel as the tank was empty during its winter storage, the boat having run out of gas on its final voyage last autumn.

- My initial thought is that all of a sudden there is something wrong with the fuel system, as the engine is turning over. Just to be sure it was not a weak battery that was at fault, I connected my car battery (that I removed from my car and brought down to the dock) with some jumper cables but this made no difference and gauges did not activate.

- Online research has me thinking there are other clues to what might be causing this no start. In recent seasons, the engine was stalling every so often when easing back the throttle to idle in neutral. Could this mean the IAC valve needs replacing? But would its complete failure cause a no start or just a rough idle?

-When I bought the boat three years ago, was advised the fly wheel would need to be replaced at some point as the sound of it on start up suggested it had broken teeth. However this sound has not worsened and would surprised that this could suddenly cause a no-start just a few minutes after the engine had successfully fired up.

Any thoughts would be greatly appreciated before towing the boat to the launch ramp and trailering it back for what's bound to be an expensive fix at the marina.

 

Welcome to the Forum dtmmore.

Sorry to hear about your dilemma.

Too many variables to diagnose over a forum but it sounds electrical and fuel related to me.

Simply start replacing anything suspect. Keep the replaced parts until you know they are faulty.

Good luck. Let us know how it turns out.

 

Thanks BB!

I got lucky and shortly after joining the forum I came across a thread on another site where the gauges were not coming on as usual ... tried the same fix and engine started first time .. had unknowingly flicked the kill switch! "You're not the first, and surely you won't be the last" was the final post on that thread. Curious to know why the switch kills the gauges as well as permits the engine to turn over (but not start). Boat does not get much use so this bit of luck saved a tow down the lake and perhaps a long wait time for a boat mechanic to diagnose the problem!