Yamaha gauge fuse problem

[max366]

I went to run my twin 2001 200hp OX 66 engines and they started ok, but the gauges were all blank. I checked the wiring diagram and found that the fuses in the wiring harnesses. Port engine had blown fuses blown while the stbd had the fuse in the yellow wire blown. I've never had a bit of trouble- seems strange that this occurred out of the blue.

Any ideas on what might have caused this?

26' Black Watch
T200HP Yamahas

[jtburf]

One idea did you by chance charge the batteries with the key's on !!!!! Just a thought ....John

[max366]

Nope- no charging of the battery. Just shut off the engines with everything OK, came back 2 weeks later and the fuses were blown.

26' Black Watch
T200HP Yamahas

[knotwanted]

Max.. Have you replaced the fuses? The fuse on the yellow wire is for key on power going to the gauges. Did the fuse blow when you tried to start the engine or when you turned the key on? Will the Stbd engine turn over without replacing the fuse? Check the battery cable connections. They must be tightened more than finger tight or you can have high resistance and could blow a fuse. Check each engine one at a time to see if either will crank without blowing a fuse. Also see what is connected to the yellow wire, other than the gauges. They may be plugged into a blue wire on the gauge to illuminate the gauges when the switch is turned on. If so disconnect this to see it this eliminates the fuse blowing on the yellow wire. Good Luck and Good Fishing.

[max366]

Knotwanted,

Interesting point about the batteries. The gauges never came to life after turning the key to on. The fuses seemed to be blown before turning the key. The engines started in spite of the gauge issue.

My port battery was weak and I used the crossover switch to start the engine using the stbd battery. Wonder if the low battery indicates a leak/short somewhere in the system? Wouldn't a low battery cause high amp flow?

26' Black Watch
T200HP Yamahas

[knotwanted]

Yes low battery voltage does increase amperage draw and can cause a fuse to blow. Also I've seen fuses below because the battery cables are not tight. Make sure the battery cables are tightened with a wrench or pliers. The ox66 engines require 12 volts to run properly so make sure both batteries are charged. Many boats are rigged with the automatic bilge pump switch wired to pull off of one the starting batteries even with the battery switch off. This may have been what pulled the port battery down.Good Luck and Good Fishing!

[KevinM]

Corroded connections will also increase current draw. I have seen some so bad that they became heater circuits because of the corrosion/higher current draw!