I have a fish hawk 840 thermo troll that is getting scattered readings, nothing consistent. I have sent the unit back to the manufacturer to have him look at it, sync the probe with the display head and have replaced the transducer. I've turned off my depth sounder thinking it might be causing the interference but it is still being interfered with by 15hp Johnson kicker. I have replaced spark plugs with resister type I put dieletric grease in plug caps. Still getting interference. Hooked unit to its own battery seperate from any motors or electronics still getting erratic readings. Any help or suggestions would be greatly appreciated. Thanks.

what or where are the wires routed near ?

try rerouting wires away from any thing that could cause rf
especially battery cables or other power wires or tachometer leads speaker wires or speaker magnets
also if the kicker has a charging system the rectifyer on the kicker could be bad letting ac current into the 12dc circuit

Frank
calumet marine

Where is your F H transducer in relation to your kicker motor? I had my F H ducer to close to my kicker and it would not read right, moved the ducer to the other side of boat and worked perfectly, had something to do with the prop wash from kicker.

Hi thanks for responding. The fish hawk was wired to a 12 Volt battery not hooked to anything else. The transducer is on the opposite side of the boat furthest away from the kicker as I can place it. The transducer cable runs at the bottom of the hall away from any other wires. I'm stumped.

Hi I moved tranducer to the other side of the boat last year .This year i put a second battery in the boat not hooked to anything but the fh and only the fh Still getting scattered readings I may try to replace rectifer I have not tried that but I kind of thought it might be the charging system thats why I put it on it,s own battery wierd thing is it works when the big motor is running and kicker is off But I cant troll with 235 Hp goes too fast 4.9 mph.... Thanks for the help

does the kicker have a charging system ?

just disconnect all the wires from recifyer and try it if the static goes away then replace the recifyer