static and white screen on depthfinder

[randy]

I have a 1197 hummingbird on boat that I get alot of static when going faster than 5or6 mph . The higher the rpm the more static until finally its a white out. I got the finder wired to fuse block hooked to starting battery as I got trolling batterys wired 24 volt. Is their some kind of resistor to wire inline at the battery. Any help appreciated

[SeaCatMich]

1. What transducer are you using and what mode is the fish finder in (dual mode, side finder...)?

2. Have you tried wiring direct to the battery instead of through the fuse block?

3. What is your engine?

[randy]

18' Alaskan with a 90 merc 4 stroke.i think it is on the dual 83/200.

[SeaCatMich]

The outboard is new enough that I wouldn't think it is causing any spurious electrical signals. I would lean toward the grounding of the fishfinder being the issue. This could be the fuse panel, the wire running from the battery to the panel, the connector on the end of the fishfinder power cable, or the boat's main ground.

Easiest way to test is to run the fishfinder power directly from the battery. If it resolves the issue then the problem is either the panel or the battery to panel wiring. If it doesn't, then I'd check the overall ground. Another indication of this would be if you are seeing the same sort of problem with your VHF radio getting lots of static when RPMs go up.

[randy]

Thanks Ryan, I'll run a separate feed and ground to it. Appreciate it

[Rascal Trophy Fishing]

Regarding that ground wire, most mfrs. equip the units with a very thin wire, not good. Change that to say a 14-16 gauge wire and try it, worked wonders for me.