Fuse location 135 merc black max

[Uncle rex]

After replacing the steering cable on my 1987 Glassstream 17 Bass boat I do not have power to the instruments. It is a 1986 Black Max 135 Mercury. Can some one help on trouble shooting the problem?
Thanks

 

[Chris1956]

Re: Fuse location 135 merc black max

Looks like a fuse on the main harness. Look for a red wire and trace it until you see an inline fuse. The wire color may change to red/purple, at the fuse.

 

[sam am I]

Re: Fuse location 135 merc black max

Thinking here.......It's properly not an engine fuse, that doesn't power gauges typically.

The gauges however(on my raft anyway)......temp/voltage etc., derive their power off your start batt. typically and that then is switched on/off by your ignition switch which inturn is powering your gauges. There should be main feed with a inline fuse coming forward and feeding your ignition .......usually close to the batt and maybe 30 amps.

However..........It appears if the manu didn't wire as above, they sometimes use the inline that should be close to the starter solenoid for your gauges(they are tapping off the purple wire for the gauges in this case). This engine fuse(as per my schematic/s) would also energize the starter solenoid though. Does the motor crank over? If so, then that fuse is good and I'd be looking for an inline fuse as I indicated above as in how mine is wired.

 

[Chris1956]

Re: Fuse location 135 merc black max

Sam, A lot of times the gauges are run off the purple ign accessory wire. That is typically fused under the motor cowling. Stuff other than the gauges would be typically powered directly off the battery. I use a "Master" dashboard switch to control power for stereo, FF and other items, or anything with a high current draw.

 

[sam am I]

Re: Fuse location 135 merc black max

Agreed......Mine though(that's why I added the "however" paragraph, not all are like mine but some might be, just covering bases) is wired/designed such that as to limit the paths off the main under cowling fuse to only three things......The main fuse feeds(through the ig sw.).......the starter solenoid(yel/red) when in start position, and only one load from the purple wire in run position, the warning module(which btw, is not needed to run but....), and choke(yel/blk) when pushing in on key.

The ig. switch also(genius IMO)switches through different contacts that other feed I spoke of coming off my batt that runs all "other/non-essential" switched devices such as gauges for example and/or heavier switched devices if they were to exist.

The theory, wiring it this way was to limit all non-essential things that could potentially take out your main fuse's critical functions(starter solenoid, choke and warning module) and prevent you form starting up and running.

I tend to agree with this, I could give a rats butt about a dumb voltage gauge(or path to) if it and/or something else on that switched circuit hung off the purple wire that happens to short taking out my main fuse and cutting off my ability to start up.

These older merc's, to start them?......you just have to turn them fast enough, the mag does the rest.......if you loose the ability to turn them cuz of a shorted gauge taking out your fuse?....well.

It's actually harder to figure out how to shut them off(not realy but ya know what I mean).......lol

 

[Uncle rex]

Re: Fuse location 135 merc black max

Thanks Guys I thank you for the information. I am planning to work on the Boat tomorrow.