1975 Mercury 7.5 or 9.8???

Hello,

I purchased a Mercury outboard the other day that has no decals on the hood. A previous owner down the line took off decals and rattle canned the outboard to death. The person I bought it off of couldn't tell me if it was a 7.5 or 9.8. There is a serial no. 4251968 on the transom mount plate and I matched the same serial number on the block. Serial numbers leads me to conclude that it is a 1975 model but I don't know if it is a 7.5 or 9.8! Are there any markings on the block that would point me in the right direction? Any help would be greatly appreciated.

Thank you

Is there a decal on the block that says ----Comet ------That identifies the 7.5 model.------Or remove that narrow bypass cover with 3 screws.----Then measure intake ports and post the diameter here.----The 7.5 had smaller intake ports.

Thank you for replying racerone. I'm attaching a couple photos. Is this what you mean by comet decal?

Correct those were put on the 7.5 models.

Thank you for helping me identify this outboard racerone! Have a good evening.