electical fault - advice wanted

[boristhebold]

Ive been having an intermitant fault with one of my yamaha guages shutting off when I hit moderate waves, I changed the inline fuse holder on sunday morning early before the round isle of wight event and it seemed to improve.

However, after a battering due to south west wind and sea state on my way back from needles to Poole both guages went off.

When I reached studland bay I dropped anchor and went to switch engine off, engine would not switch off, even removing kill cord would not switch engine off. After several attempts finally engine switched off.

As im not an electrical engineer my simple thought process makes me think either a bad earth/negative connection or a bad pin connection somewhere, as the ignition, kill cord circuit and guage circuits use same wiring harness.

Any ideas so I can narrow down where the issue is. The engine did restart but both guages off.

[Davie]

Run a wire from the neg battery terminal to any black wire on the back of any gauge. You have a broken wire somewhere in the harness.

[Nightfisher]

Clean your ground wire connections or better yet, cut the connector, find clean wire within the wire shield. Crimp and Solder new connectors. Do both ends, froam fuse panel to batter/battery fuse. Frankly as said above, I'd replace the black (neg) wire from the battery all the way to the fuse panel, And fuse panel to the main gauges negative. I'd do all other outputs from the switch panel to all lights, pump and any other electronics. Remeber to use 10 gauge feed wire from battery if your running only standard draw items. Add the amp draw on every item (look up online), the length of run from battery then look-up the guage of wire needed from battery, crip and solder connectors. Sounds harder than it really is. Better being safe than sorry be sure to include a main batter fuse at 75% of the full amp draw rating of all equipment on. Heavy loads such as Electric Motors must be direcly hooked to tha battery and fuse 8 inches away from battery. Good Luck.

[boristhebold]

In the end I found a loose wire connection inside the unit, fresh bit of soldering and should be sorted.

one question I have, when I put it all back together and connect the speed pressure PVC tube back on to the back of the guage should I run the engine until water starts to come out of tube and then connect it back in because ive noticed while its been off there is air in the line and hence if i connect it back up like that surely the air trapped in the line will prevent the water going up the tube to the pressure sensor ?

[Pikey Dave]

Originally Posted by boristhebold

In the end I found a loose wire connection inside the unit, fresh bit of soldering and should be sorted.

one question I have, when I put it all back together and connect the speed pressure PVC tube back on to the back of the guage should I run the engine until water starts to come out of tube and then connect it back in because ive noticed while its been off there is air in the line and hence if i connect it back up like that surely the air trapped in the line will prevent the water going up the tube to the pressure sensor ?

No need to bleed the pitot tube, the pressure will be equal along the tube & register on the gauge. It will be an advantage not having water in the gauge, less chance of corrosion.

[Fender]

Originally Posted by boristhebold

Ive been having an intermitant fault with one of my yamaha guages shutting off when I hit moderate waves, I changed the inline fuse holder on sunday morning early before the round isle of wight event and it seemed to improve.

However, after a battering due to south west wind and sea state on my way back from needles to Poole both guages went off.

When I reached studland bay I dropped anchor and went to switch engine off, engine would not switch off, even removing kill cord would not switch engine off. After several attempts finally engine switched off.

As im not an electrical engineer my simple thought process makes me think either a bad earth/negative connection or a bad pin connection somewhere, as the ignition, kill cord circuit and guage circuits use same wiring harness.

Any ideas so I can narrow down where the issue is. The engine did restart but both guages off.

Personally if I had a similar electrical issue with the engine not switching off I’d get back to my home base quick smart before chancing that the engine would start again, you can worry about fault finding once safe back on your trailer J ( clearly if the magic electrical smoke appeared then a different course of action would be appropriate ).
Glad it worked out OK

[jyasaki]

Originally Posted by Pikey Dave

No need to bleed the pitot tube, the pressure will be equal along the tube & register on the gauge. It will be an advantage not having water in the gauge, less chance of corrosion.

The speedo is actually supposed to read air, I think. It's all air when connected, and there's no escape valve to get water up the tube when the boat is launched. That means normally, the water going into the pitot hole pressurizes the air in the tube. Most likely doesn't matter either way, but I also don't think it merits worrying about.

jky