ive got a motorguide 4 743 trolling motor,,,,it pulls boat good even in wind for my needs,,,,however id like to have one that cut milfoil better....any prop suggestions,,,,and how do i tell what size prop i have ?

According to the parts list, your motor is the 3 1/2" diameter. This is a list of what is available:

http://www.iboats.com/Motorguide_Replacement_Props/dm/view_id.39213

Another is the new Safari prop (3 1/2") and is supposed to be excellent in weeds, but I have not used mine in weeds. Some have and are pleased with its performance. Is is a slower speed prop though.

well that helps me out ,,much appreciated,,,,im allready tired of raising my t motor to pull hydrilla or milfoil out of the prop......lately just finding flats and drifting with both motors up......

i also just bought a humminbird 565 and am worried about mounting the transducer ,,,,,any help or tips thier id greatly appreciate as well

The new Safari prop is awesome. I tried mine out this past weekend and the only time that I had to remove weeds was when they completely covered the entire head and shaft. The rest of the time it cut through some very thick and nasty stuff without getting loaded down with weeds. I had no problems driving up into the thick stuff. Wiht my old 3 blade prop I was having to pull weeds off every few minutes.

As far as the transducer, exchange it for a trolling motor puck type and you will have less trouble in the weeds with it as opposed to the transom type that is supplied in the box.

Your next best option is to use the transducer you have with a Transducer Shield and Saver as it is more hydrodynamic than the puck alone.