2002 22i - Mercruiser 350 MAG - Engine Won't Fire

[youngc]

The Merc 350 on the 22i will not me turn over. It cranks but will not fire. I have fuel to the fuel rails, power to the plugs, fuses all seem good, but still it just cranks and won't fire. I had taken on it the lake and was running it (idle and moving) for about an hour. As we were running it across the lake, I turned on an aftermarket depth finder. As I turned it on, the engine died and has not been able to fire up since. I'm not sure if this was just a coincidence or not, but figured I'd mention it.

I bought this '02 22i last season and ran it 4 separate occasions until the season ended with no problem and used the depth finder every time. I have been searching every where for an answer, but cannot come up with anything. Is there something obvious I'm missing? Is there a "hidden" fuse that could be cause the motor not to fire?

Any help is appreciated.

[youngc]

Here's a video of what's going on.

https://youtube.com/shorts/-yALqSv2g8U?feature=share

[FlyinFishTX]

I had a similar issue on my '07 20v where it wouldn't fire. I discovered that if I started the boat while the fuel pump was running (building pressure or priming, I guess), the boat started every time. Haven't had an issue since. Worth a try.

[youngc]

Thanks for the response FlyinFishTX

I hadn't tried an "immediate" start, but unfortunately, that was not the solution to my problem but thanks for the info. It's too much of a coincidence the engine stopped firing when I turned on the depth finder so I'm thinking somewhere electrically is bad.

All my plug have power, plugs are new, power to the fuel injectors, fuel is in the fuel rod, starter works, every fuse I've found is good. Are they any "hidden" fuses that anyone knows of on or around the motor? I've searched it over for hours.

I'm hoping it's not the ECM. I'm trying to get my hands on a diagnostic tool to see if that can give me some codes.

[youngc]

gumby Thanks for the information. Going to get after it this afternoon. I know my fuel pressure is 40 psi, I’m getting spark to the plugs and off the coil. Injectors seem to have power as well from my light test.

I’m going to test voltage at the coil today to see if I have enough juice to the plugs. I’m hoping this is it. This is the only electrical test I haven’t done.

I topped the fuel when I winterized it so I don’t think water could be in there. Just seems like timing is off which makes me think worst and it’s the ECM. Will let you know.

[youngc]

Well it had good voltage, power to plugs, pulse on the injector and fuel is good. I'm taking it in to a local marine motor guy to see if he can diagnose further.

Appreciate the help on this.