Looking to buy a scan tool for Mercruiser gen 4.

Have them all, so you would need to be able to scan MEFI 1 if your set up is OEM stock ??

Rinda
https://www.rinda.com/marine/marine.htm

how much?

rinda / diacom only has 2 scan tools for sale - the techmate pro and the laptop software version. if your not going to be working on a handful of boats then The hand held would be a good choice. Ill pm u the best option. I own and have operated every marine scan made on the market. Actually for the the Mefi s 1 thru 3 and the ECM / PCM 555 the DDT and if one is wanting a hand held the DDT rather than Diacom hand held is a best option. PM sent

Still looking!

MEFI Scan 1, cCD (mefiscan1) $195.00 @ OBD Diagnostics, Inc OBD Diagnostics

Its not for mefi (marine efi) it uses the automotive obd2 connector, its for auto

OBD Diagnostics This works just fine for my 2 AS&M EFI 575s ..........