re-wiring 1988 bass buggy pontoon, would like some help

[Jasindude1]

So, searched all online and of course couldn't find ANYTHING about a wiring scheme, called Suntracker and no luck there, so turning to the forum peeps, Here are the issues i am having, no speedo, no tach, no water temp, voltage gauge works, opened the console and man wires running everywhere some not connected to anything, just a total mess, I have a 6 fuse box that has 5 glass fuses on it and dont know what they ever go to. Lights work, fish finder works, cig lighter, anchor light doesn't, no radio and bilge doesn't work. Besides that runs and drives fine, ok so first question, i want to track down the speedo and tach issues, do I need to run a fuse to the gauges? I have been reading yes you do, or wire all all gauges to 1 fuse, ok well what size fuse? 1 ordered a circuit breaker box with 5,10,15 amp fuses breakers and a box of 5amp breakers for the front panel accessories. Replacing the front old lights with 120w LED lights, installing a stereo, and replacing all old corroded wires. So any information on wiring, fuse recommended sizes, how to track down tach and speedo issues, (the water temp doesn't have the wire to the motor.) Tach really more than anything bc i wanna be able to adjust idle. The lights and switches and wires im just gonna scrap and buy all new switches and run all new wires. So if u can tell me what the glass fuses wiring diagram is, help with gauges or have any insight or maybe done this urself please i would really appreciate some help or guidance, i have never wired a boat before, but i have re-wired many cars, motorcycles and installed many after market electronics.

 

[jlh3rd]

I re-wired my '07 lowes pontoon boat last year. It was a rats nest also under the console. I added individual positive and negative buss bars, a battery master switch to feed my individual circuits and added a stereo switch also.
Originally, it had only 4 switches, one was an accessory switch not used. I left that and added the battery and stereo.
I also added a main battery and aux battery selector switch, and an automatic switching charging module. I kept the factory fuse from the main harness....I don't know what that is, I'll try to find out. The 4 individual original circuits have 5a re-set breakers, the battery master I added I put a 10a breaker on. Maybe that is wrong but the maximum amp draw total from my individual circuits does not exceed 10a....My limited knowledge of circuits and amp draw says basically that is ok.....everything works....so...
My point also is that I used Newwiremarine as a great source for switches, breakers and info. Have you tried them?
Also, Id suggest if your gonna spend that amount of time, I'd at least get rid of glass fuses and put in modern fuses.....or if you can, push-to-reset breakers......that ,of course, depends on instrument panel space....I was cautious and careful in my planning when I had to cut two new rectangular spaces in my irreplaceable panel to add the two new switches....measure twice, cut once.......
Engine instruments are wired from the "key on" circuit. Gotta be a fuse/ breaker on that, I'll try to find that...
My old speedometer worked on water pressure, the only electrical it needed was backlighting....I added smartcraft tach and a gps speedometer. The tach uses mercury engine cable from computer now, and the speedo is simply analog connected to the "key on" circuit.
Analog tachs, aside from being connected to the "key on" circuit, has a separate signal wire ...and... the tach itself has a selector switch on it for the type of "charging impulse " the engine uses....or something like that...google it......it can be confusing. If it's set up from the factory and hasn't been touched , it should be set properly......but if not, well, google it.......

As simple as my pontoon was, it was still a headache to decipher what I needed to do for upgrading...as you know.......so all of this is fyi and fwiw.....
I plan to go to the boat today , and I'll try to take pics of what I did....
here's this:

 

[jlh3rd]

and...for a start...

 

[ahicks]

I can add 1 hint. Unless you are talking about the light, there is no power necessary for the speedo. It runs on water pressure fed from the pick up on the back of the boat.

 

[stylesabu]

tach and water temp are on engine harness,look for motor schematic for these 2. other wiring is basic boat wiring, speedo could run off paddle wheel. look at back of speed if it has a fitting size of windshield washer tube runs off pressure, either fitting on lower unit or bass pro has plastic sender cheaper that attaches to back of boat, you will have to attach it to one of the pontoons. chase down one wire at a time,use ohm meter to check continuity. because of age, you will probably fine corrosion

 

[Silvertip]

Every gauge has an internal back-light for running at night. So yes - 12 volts to each gauge is required but it comes from the Nav/Anc switch typically. Some have that line powered any time the ignition switch is on. Not what I would want but some folks are terribly forgetful and turning the key off kills that line.