Boat electrics/gauges faulty.

[DavidMBowman]

Hi
Bought a Bayliner 160 OB
Non of the gauges work.. We’re working around it..
is it more likely that they are just broken or could they all be linked to a common single fault or corroded connection?
Ive started trying to trouble shoot. The fuel gauge is registering half full all the time. So i remade a couple of connections at the sender end. They were actually poor and corroded. But also an earth wire (yell/green) is disconnected and I cant see where it might bolt on??
where does the Speedo and rev counter get its signal from?? Gearbox or engine head??
And I have a brown and white wire male in the engine head that is not connected to anything but there is a black wire female but a bit nervous to just join them up
Any help would be really appreciated.

 

[vas]

earth connections buggered?
engine block for stray yellow/green is a good place to start re debugging wiring. or back to bat negative.

 

[rafiki_]

It is likely that you have a pitot speedometer on the Bayliner. You should see a small tube mounted on the transom with wiring back to the speedo head. I expect the Rev counter to work off the alternator. Check all connector corrosion as Vas says.

 

[ChromeDome]

Instruments belong to the engine, not the boat (may be branded but still came with the engine).

The OB in the boat model name indicates Outboard, but you didn't mention engine make/model. Since Bayliner is a Brunswick company along with Mercury and a bunch of others, my guess is that you have a Mercury 90 hp, probably 4-stroke. If it is EFI most electric signals would come from that system, somewhere central in a black box.

A manual with diagrams will tell.

If the pitot tube is part of the engine instrumentation it would be fitted to the outboard, sensing the pressure on the leading edge of the lower leg, when moving forward. It works by pushing the air in the tube towards the gauge to give an approximate indication of speed.
If at any time the tube has been leaking the pressure will fill the tube with water up to the leaking point, resulting in water in the boat and probably the instrument itself. If a leak is on the tube i below the waterline, the tube can siphon water into the boat the even when moored (don't ask!). If you decide to measure speed by e.g. a GPS or app, make sure you block the tube off properly or just remove it - at least the part outside the boat.

A manual for the boat itself should be available from Bayliner.

Showing a Yamaha, but same thing:

 

[DavidMBowman]

Wow some great accurate and very informative answers there!! Thanks very much I’ll start investigating. Yes it’s an outboard Mercury 90 but it’s a 2 stroke. Runs very very well. Circa 2005. Quiet on tickover up to about 10mph so very handy for the lakes. I’ll update if/when I find out more. Again thanks for the info. Much appreciated.

 

[DavidMBowman]

Ok so I’ve cleared the tube and blown up and down the pipes. The speedo defo moved a little bit so hoping tomorrow it’ll be working.
no luck with the fuel level. I’m looking at stuck sender I think. I’ve found a multiple connection to the neg on the battery quite green so that’s next on the list. But I havehad speedo lights come back on but lost the bilge pump ?. I’ve got a few photos but seem too large to post. How do I reduce the size of them to be accepted on here?

 

[DavidMBowman]

Oh think I’ve managed

 

[DavidMBowman]

And more. The guages have Talia or Falia on the speedo.

 

[DavidMBowman]

Just an update. The speedo works! Thanks for that. But sadly we had a mech breakdown this week. In a two pronged attack the throttle bar popped off and the gear selector has sprung out of adjustment. No reverse and jumping out of forward at mid revs. !! Throttle easy remedied and I’m into the remote box for a look see. ( although it has freed up whilst I’ve been dismantling!). I’m going to continue and inspect and lube up the box whilst checking for damaged parts. No kinks in the wires and engine head area is well lubed up. Any ideas what causes that kind of failure. ? We’d been cruising at 7mph for 10 mins steady revs. Regards David.