Kicker and Sonar Interferance

[Ringo]

I've got a Garmin 942xs with GT21 transducer and a 9.9 Suzuki kicker. With my main engine running, Suzuki 140hp, Garmin picture is clear in both 200 and 50KHz. When running the Kicker and at medium-high RPM, the screen goes completely blue in the 200 mode. I can track my DR balls when switched to 50Khz but can't mark any fish. Kicker and main are connected to the starting battery and the Garmin is wired to the deep-cycle house battery. I tried disconnecting the kicker leads and wired to the house but still have the same issue. Also replaced the spark plugs on the 9.9 in case of any noise but still had no luck. Both the kicker and Garmin are professionally installed and wired through the haul. Anyone with a similar setup has the same issue?

 

[zurk]

add some doel fins to your kicker. the doel fins smooth out surface aeration from the kicker by blocking prop ventilation and the main thing which interferes with sonar is mixing air with water resulting in broadband noise from bubbles popping. if you dont want doel fins i would remove the circular prop guard. that thing is probably causing a ton of vortices, ventilation and noise in the water which will disrupt sonar signals.

 

[gone fishin]

based on what I see on your photo I can not see any way your kicker should interfere with your sounder unless your prop guard is causing the problem
I would try taking off the prop guard and see what happens

 

[Unreel]

Any chance your sonar cable is running along side a power cable from the kicker?

 

[the force]

My kicker causes a ton of interference from bubbles when back trolling (will lose bottom signal), however is fine in forward gear… a bit surprised it would cause interference moving forward but may be the culprit.

 

[Charlie415]

Disconnect the charging circuit to see if it is electrical interferance or prop wash. I would put my money on transducer wire getting electrical interferance. Re-route the transducer wire away from the kicker charging circuit or if possible away from any current carrying wire.

 

[Ringo]

Thanks, guys. There isn't really much interference when the kicker is in idle or low RPM so it may have soemthing to do with vibration or aeration from the prop. I'm going to start with the easy fixes and isolate the wires as much as possible. Will do a test when out on the water this Saturday.

 

[Reel Time]

add some doel fins to your kicker. the doel fins smooth out surface aeration from the kicker by blocking prop ventilation and the main thing which interferes with sonar is mixing air with water resulting in broadband noise from bubbles popping. if you dont want doel fins i would remove the circular prop guard. that thing is probably causing a ton of vortices, ventilation and noise in the water which will disrupt sonar signals.

put the kicker in neutral and test this theory first.

 

[Alan Wilson]

I have the same setup with a 3 Lowrance HDS unit and no problems

 

[Rayvon]

Can't see how it could be aeration with the transducer on the opposite side of the boat,must be a wiring issue as "Unreel" suggests.

 

[BC Coast Pilot]

Double check they gave you resistor plugs when you changed them? Tough to find a great parts counter guy that gets it right. Secondly check the power cabling proximity to transducer cables. looking at the transducer being like 4ft from the kicker I wouldn't suspect aeration from kicker however do rule it out.

 

[easydoesit]

A couple of things to consider:

50 kHz will have noticeably less resolution than 200 or 90 kHz due to physics - not the best for spotting fish.

Your trim tabs are close to transducer and will Cause turbulence - are they out of the way when trolling?