I have a 1987 28' Saber with a 502 in it and am having some problems with it not always starting at the starter. I replaced the ignition switch a couple months ago because it was acting up.
Only sometimes, when I turn the key to start, I can hardly hear ONE quiet click that seems to come from the solenoid, but I'm not sure. Sometimes I have to turn the key 20-30 times and then starter will take off fine. Sometimes it turns over on first attempt. Is this something in the starter solenoid or a short in the wiring somewhere else? Where should I look first? The wiring from the new switch, from the battery to solenoid, or pull starter?? Any help would be appreciated, and please be patient, electrical wiring is a big downfall for me...

Likely the solenoid. If it is not bad keep the original for a spare. Not too hard to swap out on the water and they do go bad. I suppose you have checked grounds and condition of all wires?

I don't know what kind of starter/solenoid that you have, but if this applies, check the small screw on the solenoid: holds and connects the copper strap, which goes directly from the starter motor to the solenoid cap. It needs to be tight.

First check all your wiring/connections & battery.
Merc uses a remote slave solenoid/relay to actuate the starter. It's usually located by the red breaker button on the engine.
Buy a $10 test light. The next time it happens, have someone turn the key (crank position). Check the yellow wire on the side. If it's hot, the ignition switch is OK. Then check The yellow/red wire on the relay that goes from one of the bigger post down to the starter. If it's hot, replace the starter. If not, replace the relay.
Gary

I think Gary is on the right track the assist solenoid is is more likely the culprit, located by the breaker on the engine. A quick check if you can reach the starter easily is to put 12 volts to the inner small terminal on the staters solenoid. If it turns over without hesitation change the assist if it don't yank the starter.

Phil

Been there, done that, bought a new slave solenoid. All is well now.

It 's located, on mine anyhow, at the starboard front corner of the engine. Mounted with the engine circuit breaker.
Easy way to tell if that one is bad, take a pair of pliers and jump the two large threaded terminals with the handle ends. If it cranks easily then that's the problem.

Always use a jumper wire first attached to the small inner terminal then put power to the jumper, arcing across the terminal can ruin the threads making it a bear to get it apart down the road.

Phil

Thanks a lot guys. I did jump the starter and it turns over fine. Tonight I will test the slave/assist solenoid because that sounds like it might be going bad, as long as the ignition switch is working. Thanks again, MIKE.