Hey I mounted a Lowrance Mark4 on my Revo13 last night. What model is that you have? Any pro/cons/thoughts/uses?
Lowrance Elite-4. Honestly, I have mixed feelings about it. Out there in the ocean I get great readings when the depth is less than 150ft, but when I get out to the ledge where I normally fish for tuna (275-300 ft) I don't see much fish activity or detail on the bottom. Part of the reason might be that I have the transducer mounted inside the hull in a block/puddle of marine goop; so perhaps performance is better when the transducer is actually exposed to the surrounding water. If you're doing shallow water or freshwater, you needn't worry about this as much as I do.
The GPS works quite well on my unit, even without the navionics chip.
Helpful tip: if your model has the two ports open at the back, you're only using one for power/transducer. Cover the other port by whatever means necessary so it doesn't get exposed to saltwater. I saw corrosion after the first time my alt port was exposed, so then I cleaned it up with a q-tip and wd40 and then sealed it with a rubber cap.