GT-40 No Start

I've had this nagging power loss issue over the last two months. It finally left me stranded at the River Ruckus this year and had to limp back to the dock early. It was kind of hard to diagnose because it only happened once or twice and was infrequent. All of a sudden, I would lose power to the fuel pumps and the engine would die and not restart. Not fun when you are underway...

I was getting voltage (12.0+ at the dash), the engine would turn over, but the ignition wire going back to the computer had no power. It took me a few trips to get this figured out, but it finally happened once when I was in the driveway and I was able to troubleshoot properly. Any guesses on the solution? (I'm sure you'll get it quick.)

99 Sport - GT-40 engine

Is this a quiz or something?

Any prize for the winner?

Yep, those two were the first items on my list (relays and laynard), but it ended up being the Neutral Safety Switch. I was using the GT-40 manual wiring diagram and the NSS isn't listed as a component in the circuit. Any idea on why this would cause an issue with power to the ignition wire? The motor would crank and not start, but had full power to the dash.

Good job. Keeping it simple.

I could be totally out to lunch here but you have a 50 amp fuse and a 12.5 amp breaker feeding power to your ECA relay. The fuse is in the battery box and it seems to me that if you have some corrosion in the holder, sometimes it may conduct just fine and other times not at all.

See this attached link about the fuse. According to the link there was a retrofit to remove it and some boats probably don't have it anymore
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link

Also this PN link talks about issues like yours. It covers your symptoms pretty well, crank but no start Posts 3,4 and 5 are really pertinent

PN link

The wiring diagram in the GT 40 manual you mention does show this fuse and a 12.5 amp breaker going to the ECA relay. (Numbers 14 and 15 on page 6-8 and 6-10)

As another thought.maybe the breaker is having corrosion issues at the wiring connections that could be cleaned up too.

Maybe you've already checked this stuff and it's not the problem but I figured it was worth mentioning.

Wanted to follow up on this post. During some Summer maintenance I moved my battery from the bow to under the observers seat. My battery terminal connector was split in half and think this was causing some of my electrical issues. My alternator decided to start chewing up the belt so I replaced this, too. Either way, I replaced both with new and haven't had any issues since (at least 15-20+ hours). I'm now confident again in my boat running well!