Fish finder Interference

JetPen

Recruit
Joined
Mar 21, 2017
Messages
3
I have a Yamaha XL1200 jet ski and have had a Lowrance Hook 3 installed on it. The finder has been replaced several times because of inteference.
To check the source of interference I have removed the wiring and left only the transducer mounted on the outside of the hull with the cable exiting the ski at the rear hatch. When the ski engine is not running the screen is clear (even though the transducer is in air) but the moment the engine is started the screen shows lots of rubbish. I have powered up the installation with a bench power supply totally separate from the ski battery and moved as far away from the ski as the cables will allow but I get the same result.
As there is only about 2 foot of transducer cable in the ski and its away from power cables etc I am at a loss as what can be causing the interference. Anyone have any ideas? IMG_0218.jpg

The attached pic shows from the center to the left without the engine running and from the the center to the right with the engine running.
 

dingbat

Supreme Mariner
Joined
Nov 20, 2001
Messages
15,414
I suspect you have a transducer problem or the gain is set too low.

Shooting thru air, one would expect to see something like the screens on the right.

The unit showing 13.1 volts without the ski running is also suspect
 

ajgraz

Lieutenant Commander
Joined
Mar 1, 2010
Messages
1,858
Unless I missed something, all your testing has been with the transducer mounted to the hull, yes?

Perhaps the jet's stream is passing under / around the transducer, causing disturbed water and screwy readings? Or maybe the transducer is just vibrating too much?
 

JetPen

Recruit
Joined
Mar 21, 2017
Messages
3
Thanks for all the replies. Eventually I removed all the wiring and transducer and placed the transducer in a bucket of water and started the ski. the screen was all clear so I placed all the slack wiring into the hatch compartment and still all clear. All the wiring was then replaced into the ski but I left slack at the transducer through the hull and placed it into a bucket. When the motor was started all was clear on the screen. The wiring path was changed only slightly. So now I will have to test it in the water and if it doesnt work then I will have to assume that the water flow is causing the problem.
 

gm280

Supreme Mariner
Joined
Jun 26, 2011
Messages
14,585
I was going to say, when you have the jetski running catch those fish and then turn the jetski off. Sounds like a plan to me. :pound:

I do hope you found your problem though. JMHO
 
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