2001 90HP 4-stroke acting dead even with new battery

[Sande Ace]

Of course I wait until 2 days before the 4th of July to get our boat with 2001 90HP 4-stroke Merc going after sitting for 9 months.

The tilt was dead so I charged the battery. The tilt worked, the gas gauge responded when key was turned on and it started and idled on the hose. The battery was 4 years old, probably good but I got a new one for safety's sake.

Now, everything's dead again. No tilt, no gas gauge response.

Any ideas? Are there any fuses, fusible links, switches that could be the problem?

Thanks.

 

[Texasmark]

Get yourself a $5 Digital Multimeter and follow the voltage. If you don't know how to use them, instructions are included with the meter....Harbor Freight has them at that price and are a super buy. From the limited info you published you may have something draining the battery or you may have drained what charge (that was on the new battery when purchased) you had by only idling. Service manuals refer to 1k rpm for minimum alternator output adequate to start battery charging....idle rpms are around 650.

A fully charged battery at standard temperature and pressure reads 12.7v at my house. A regulated alternator power supply running a charged up battery is 14.5v. Anything between those numbers is output from your alternator and rpm dependent....along with your batteries state of charge...lower the charge, lower the voltage but it rises slowly as the battery charge level increases.

On your procrastination comment, you did it to yourself....grin. Nest time you'll know better won't you....grin #2.

 

[Sande Ace]

Started with a new Mark 35A on a Sande Ace runabout in 1959 when I was 15. Wouldn't allow battery acid in it and have used the Armstrong starter on all the Cloud White Mercs I've had on it.

I was just interested if there were any go-to points on the 90.

Wally, http://www.sandeace.com

 

[jimmbo]

Was the bilge pump, lights, entertainment system left on? Bad Diodes in the Alternator can also drain a Battery

 

[Sande Ace]

I'll rephrase better. When I first tried to get it going, the tilt was dead and I couldn't lower the motor to run on the hose.

I put the 4-year old battery on the charger for a time. The tilt worked and I could start and run the motor. Problem solved??

I decided to buy a new battery to be safe. I topped it off with a 2-amp trickle charge. After connecting it, the tilt was now dead. There really wasn't enough time for the new battery to discharge.

The 4 fuses in the motor compartment (two 20A and two 30A) look good. I had suspicions about the 30A fuse on one of the negative battery wires not making good contact so put on a new in-line 30A fuse there. Still nothing.

Also, how do you tilt a 90HP motor up for travel if the electrical tilt system is dead?

Thanks for any help!

 

[Sande Ace]

I did find out how to raise the motor without the tilt working. Merc really knows how to hide a screw!

 

[Sande Ace]

Turns out it was not a single, same problem with the old and new battery.

The old battery was indeed bad. When I installed the new battery, cables were improperly attached. Lucky nothing got fried.