First time owner

[pingjockldo]

Greetings all,

First time owner of a “new to me”. 1994 1800XR with a 2004 Mercury 90hp 4-stroke. Working on some small things to get her in the water. And could definitely use some advice on the fuse block! Thanks all!

Regards,
P-

[mmwjr]

Welcome Aboard!

What is your question on the fuse block? These are cheap items and if it's giving you problems I would replace it with a higher quality one such as Blue Seas.

[pingjockldo]

Thanks for your quick response. That’s the problem I haven’t been able to find a fuse block. This connection board is the only thing I’ve found just yet. I know the outboard works because I can get the engine started (at least once before) and it tilts up and down easily. But none of the switches work on the dash or lights around the boat. So I have to be missing something. Is there a hidden location? Thanks again.

[mmwjr]

PO hacked the wiring as that terminal strip is not original nor is that wiring job. The fuse block should be under the helm. Hate to say it but you may to rewire the helm.

[pingjockldo]

Mike,

I figured as much. I'm going to do one more sweep of the boat before I start rewiring. Thanks again.

P-

[shrew]

That is a bus bar. There should be a fuse block under the helm. While they look similar, Terminal Blocks, Bus Bars, and Fuse Blocks are very, very different.

Terminal Block: This is a 1-to-1 relationship which isolated circuits. Wiring position 1A, only connects the opposite post 1B to the circuit. 2a and 2B are isolated. This allows you to route multiple circuits to the same block.

Bus Bar: One connection shared by all posts. This can be either a positive or negative bus bar, but not both at the same time.

Fuse Block. This is more like a combination of a Terminal Block and a Bus Bar. This has a single Ground and Line connection. There is a often a negative bus bar on one end, sharing the ground. The positive is distributed to all posts on the positive bus bar, however there is an onboard fuse slot for each positive terminal. All grounds are combined, but all positives are isolated from one another.

Blue Seas makes nice fuse blocks. There is nothing wrong with using a positive bus bar, but you also need to use inline fuses for each circuit, which can get crowded in tight spaces and difficult to troubleshoot and switch when a fuse blows. A wad of inline fuses tends to have the one your looking for hiding in the wiring harness.

[pingjockldo]

Thanks for the detailed response. I found the fuse block and I checked continuity of each fuse. All good. So here's the issue: still no action from any of the switches in the helm. I checked voltage to each terminal and I got around 8.5v. All the gages i.e. fuel (sorta) and battery gage shows 12v. Ignition system works just fine. I just can't get the blower, nav lights, bilge pump and accessory switches to actually do anything. Any ideas? Thanks again.

Mark

[mmwjr]

When measuring and getting 8.5V are the switches on or off? If off the connections need to be cleaned at the switch and fuse panel. Then I would measure voltage at each of the non-working items to verify they are actually getting power. i.e. measure voltage at the blower; no voltage ohm the wire between the switch and blower, voltage present the blower is bad. Note the negative may also be bad so ohm-ing from the battery negative to the negative at the blower is required.

Accessory switches are extra that Maxum installed for the owner to add stuff so they may not be connected to anything.

[shrew]

8.5v would be dead IMHO. If the battery doesn't read 8.5v, then start moving downstream. Is the positive coming into the fuse block also reading 8.5V?

The fuse holders are the connections between the fuse block back plane and the post where the wire terminal is connected. ANY of the following will become corroded over time:

Fuse Block backplane
fuse holder
fuse blades
terminal post
ring terminal
main ground to fuse block
any ring terminal on ground or positive

[yahoo82]

Since the voltage drop could be occurring on either the supply or ground side, it might be helpful to bring a long wire that will reach from the battery to the helm. Then you can measure from the helm directly to the battery and see if the voltage drop occurs between the battery + and the fuse block. should read zero volts (12 at each end). Then connect the lead wire to the battery Neg and check measure to the fuse block for 12v.

If you get 12v from the fuse block directly to the batt negative, then you know it’s an issue on the ground side. Look for a bad grounding lug, corroded battery cables, etc.

My friend once found his corroded negative battery cable on the floor of his bilge which broke off the grounding buss bar behind the motor. His systems worked but with lots of gremlins because they each found some other path to ground (presumably thru a much smaller cable which created a big voltage drop to ground).


Sent from my iPhone using Tapatalk

[pingjockldo]

So I think I have narrowed it down to the supply side (so I am going to need to build a new supply cable and ground just in case) based on all of you guy's input. I disconnected the fuse block completely and took readings across the ends (supply/ground)- 8.45V. Then to eliminate any other connectors dropping voltage, I removed all other connectors from the battery (which is still reading 12.5v) except the ground and supply. Still dropping to 8.45v. So I am fairly certain that this is the issue (supply) since the ground is a straight run. Now it could be the ground but I'm thinking that since the 30a in-line fuse is on the supply side it is more likely something with that.

Does this logic follow? More to follow. Thanks again.

Mark

[pingjockldo]

So that supply was definitely the issue. I made a test wire and got 12.5v from the battery when I replaced that supply wire. I will reinstall the fuse block tomorrow and see what happens. At least, I know that I have good voltage coming in to the fuse block.

I'll keep you posted. Thanks again!

Mark

[mmwjr]

The fuse box gets power from the Mercruiser harness. Check the 10 pin connector in the engine compartment for corrosion.

[pingjockldo]

Mike,

I have a 90hp Mercury 4-Stroke outboard and based on my "hand over hand" there were only two wires (ground and supply) to the fuse block. I'll be putting it back together tomorrow so I'll let you know how things go. Thanks again.

Mark

[mmwjr]

Mark, my mistake was thinking I/ O.

[pingjockldo]

Mike,

No worries! I figured as much! Hopefully I’m on the right track.

Mark