Online Merc Parts?

[Forsythian]

Any recommendations for online mercury marine parts? I've got twin 60hp Bigfoots (1999), need a couple of starters, thanks!

[fishinwrench]

Both outboards simultaneously need starters ?

I have to question the troubleshooting on that one.

But if you truly need them go with "ARCO" aftermarket (available through O'Reilly auto parts), or have yours rebuilt. Merc OEM replacement units are gonna be outrageous.

[REDSOXWSCHAMP]

a starter for a '99 merc 60hp big foot-$239.08

[Forsythian]

Hey guys, I'm back.

A new solenoid did the trick on motor #1. Sticky bendix on motor #2, I've brought it home for clean & lube.

In the course of this adventure, I'm thinking the batteries are not wired in the proper series. There are two starter batteries (port & starboard) and one deep cycle. There is a battery combiner, and the previous owner has wired it between the port motor and the deep cycle. I'm guessing this was done to apply an alternator charge to the deep cycle(?).

Honestly, It's an older boat and I'm not sure the combiner works. I've a mind to isolate each starter battery to its own outboard, and leave it at that. Any thoughts? thanks

[fishinwrench]

Is it an isolator, or a combiner?

Isolators and combiners are generally installed to do the same thing but how they work is different. An isolator has an input post to take a charge current and two output posts so the charge gets distributed to two banks. The isolator uses diodes that act like one way valves to allow current to flow to the batteries but the batteries cannot backfeed to each other which prevents both going dead if one is being used while no charge current is present. The negative on isolators is the diode consumes almost a volt of the charge so batteries don't get topped up fully when being charged and that can cause the voltage regulator on an outboard to overheat.

Combiners are really just a voltage sensitive relay hooked between two batteries that allows the full charge to flow through.

Unless you make long runs (15-20 miles at a time) you aren't putting enough charge on that deep cycle battery to make much of a difference, therefore you could eliminate the combiner.

And I would DEFINATLY eliminate it if it is an isolator.

[Forsythian]

Thanks fishinwrench, you explain it well. It's definitely a combiner. I think I will eliminate it.

While you're giving out free advice, is there an easy way to use a 12V indicator to check whether the alternator on the outboard is charging? Thanks again

[fishinwrench]

Absolutely, just takes a digital voltmeter.

Red lead to + / Black to - (at the batt., or starter solenoid....whichever is easiest to get to).

Operate the tilt/trim several times with the engine off (to pull battery voltage down a bit).

Start the motor and observe the voltage climbing until it stabilizes (between 13.5 - 14v.

Operate the tilt/trim with the engine running while observing the voltage result (it should pull down slightly then quickly recover after you stop activating the trim motor).

Rev the motor up a bit (no more than 2500 rpm if you are just running it on muffs and a water hose with no load on the powerhead) and make sure that voltage never climbs to 15v or more.

If it does then the regulator is failing.