Is there any difference between the O.S. .18 CV-R which is a buggy motor or the O.S. .18 CV-RM besides the cooling head?

reason I ask is we can get the non marine one for alot less including the marine head then we can purchase the marine one for, so if anyone can help i would appreciate it.

thanks in advance

You can go into the Tower Hobbies site and compare the HP and RPM numbers but it appears that they may be the very same engines with just the heads as the only changes.

Well, it took longer than normal, but I finally found the info you need at the OS engine site. I compared the part numbers for critical pieces such as crankshaft, crankcase, and piston/liner. These were all the same.

Here are the two links to look at:
http://www.osengines.com/parts/ev11830aa.pdf
http://www.osengines.com/parts/ev11890aa.pdf

thats what I thought, My only concern was temp. one motor runs over 200 and the other around 140 and just wondered if that wuld affect performance either way.

thanks again to both of you for helping out

As long as you drop them in a hull where the heat sink gets enough air, the air-cooled one works fine. Fortunately all of my little boats are low enough where they get more than what they need as the entire heat sinks are above the decks. I took one for the heck of it and cut off the top 3 fins and it still ran cool. When you figure that we can run them in the open air and not under a Lexan body with a tiny hole that we don't need the extra cooling.