So im a little late on getting th boat started this year... I went to the yard today st see if i could fire her up... Everything was completely dead so i went and bought 2 brand new batteries. I needed them anyway and thought all would be good once i installed. To my surprise. .. Nothing! the batteries are good and have full power but i cannot even get one light to work... Nothing! The biggest problem is that i cannot get my engine hatch open to look at wiring (seems like a bad ground to me).
By the way... The boat is a 2000 7.4 Mpi. I/O
If anyone has any ideas on how i can proceed please help!

Thanks...

Brian

Make some 12 gauge jumper wires and jump from a battery or good size charger to your fuse board or cig lighter and open the hatch.

Ummm remote battery switch PERKO turned to OFF.

Assuming your battery switch is good, check two things- there are wires that run behind or near the starter and might chafe against the back of the block- one of these goes to the main engine breaker on the starboard side of the engine (same side as starter). This exact thing happened to me while I was on the water- the wire finally grounded out and completely broke through, and I lost complete engine power but still had a few lights. I had a few cases before that where the engine would hiccup but then keep running, which turned out to be warning signs of the impending wire break. While tracking that down, I found that the battery ground to the engine block was very loose as well (opposite side of the starter in my case).

The battery switch is the first thing I looked at of course... all seems fine. Don't see how all can be good when I left her in winter then come back now and everything is dead... at least not in regards to the battery switch anyway.

The bad ground theory sounds good to me.

Anyway... thanks for the help guys... I will be at it again tomorrow.

If this is a EFI motor there is a fuseable link on the starter if there was a short it'll blow this and kill all power to everything. I'd check that first if you assume your battery switch is good.

Don't remove it and not replace it if it is bad this is what protects the ECU on the motor.

Everything is still dead!!! One of the biggest issues is that I cannot open the engine hatch to look inside! There was a line with a fuse coming from under the hatch to the perko switch and there was a glass fuse in there that I believe was broken. The whole link was corroded so I changed it out and thought that would do it but still nothing.

It's definitley not the perko switch cause I bypassed it and still get nothing.

I do not understand why I cannot get the hatch motor to work... I have two wires coming from that motor up to the batteries direct... usually (just last year when I winterized) I could just touch those wires to either terminal on batteries and get the hatch up or down depending on wich wire was pos or neg. Now nothing... why? Isnt that direct power with no fuse or switch or computer or anything?

Also... does anyone have any idea how I can get the hatch up? Shy of destroying it of course. The boat is a 2000 checkmate and the hatch weighs about 1000 lbs (gotta be at least 200 - 300 lbs easy).

Really going crazy on this one.

Thanks

remove the hatch switch and put 12 v to it,,,,, hatch will go up,,,,well,,,, or down if you do it the wrong way !!!!

Looks like you just need to start tracing power and wires- using a multimeter to trace this out would be a good thing to try.

To get the hatch open, just run a temporary jumper wire from a good battery to the back of the hatch switch.