Garmin 750s 1kw transducer issues

jeff84 · 26 November 2013, 08:10

Hi just wondering if anyone here has a garmin 750s I have just upgraded the standard 600w transducer to a Airmar tm260 1kw its not performing as it should loosing depth and bottom at about 90-100 meters and screen scroll speed is very slow compared to standard transducer have adjusted the transducer several times still no good any ideas? thanks

Chris Caton · 26 November 2013, 08:21

did you put any liquid in the housing before fitting the transducer, such as olive oil ?

jeff84 · 26 November 2013, 09:03

no I havent

Chris Caton · 26 November 2013, 09:10

that could be part of your problem, I'm assuming that you have fitted the transducer type where you bond a mounting to the hull then lock the transducer into the mounting, if so you need some fluid between the bottom face of your transducer and the hull, I was advised to use olive oil which has worked very well for several seasons, but I have read on here that others have used various gels etc with similar results, but whatever you use just fresh air won't work! when we fitted ours we just guessed the amount of fluid, but you want to try to push any air out so it's just fluid in the gap

hope that makes some sense and helps solve your problem

jeff84 · 26 November 2013, 09:13

mine is a transom mount transducer not a through hull cheers

Chris Caton · 26 November 2013, 10:48

oh, have you checked in the menu to see if you need to change settings for different transducer

jeff84 · 27 November 2013, 04:40

ive spoken to garmin and they said on this model there isn't any setting to change it you just plug it in and it will work

Chris Caton · 27 November 2013, 06:52

how about the transducer itself, is it still horizontal or has it been knocked ?

jeff84 · 27 November 2013, 07:49

Its horizontal slightly down at back doesn't go deeper than about 90- 100 meters even stopped I've just done a software update to from 3.80 to 4.10 so hope that sorts it. Maybe a faulty transducer?

Chris Caton · 27 November 2013, 08:52

Quote:

Originally Posted by jeff84

Its horizontal slightly down at back doesn't go deeper than about 90- 100 meters even stopped I've just done a software update to from 3.80 to 4.10 so hope that sorts it. Maybe a faulty transducer?

If it still doesn't work with the update can you try the old transducer again, if it works ok with that one then I would suspect the transducer

jeff84 · 27 November 2013, 08:58

good idea will try that will let you know how I get on thanks for your help

biffer · 27 November 2013, 09:00

I've got a couple of new arimar transducer with speed logs

jeff84 · 27 November 2013, 09:05

speed log?

Ovey · 27 November 2013, 09:26

I haven't got a transducer (next big purchase is a plotter/GPS/transducer combi!) but I've heard that stern mounted transducers can be affected by height above/below/on the waterline, and also distance from the prop (bubbles in the water affecting performance).

It might be worth checking the depth and distance from the prop - maybe experimenting by mounting it to a piece of wood and moving that around rather than drilling the transom?

jeff84 · 27 November 2013, 09:29

I could try that its still the same with engine off to

biffer · 27 November 2013, 10:21

Quote:

Originally Posted by jeff84

speed log?

There's a little paddle wheel on the ones I've got, give you speed if your plotter can cope with it, usually they can

Pikey Dave · 27 November 2013, 16:21

There may be a setting in the menu that tells the unit what to use as it's speed data source, gps, paddle wheel or pitot tube. Assuming you have a GPS in the system, set it to GPS