If you need the full job on it,like water cooling the head,water cooled manifold,mounts, port work, and other little things to get more out of it,chipbreakr (Jim Johnson) on here and JRCBD does a great job on boat engines.He hasn't been on here since 2015, but here's his last known email,
[email protected] and his phone number ,304-610-2287 or the last four digits may be 3287. I couldn't tell if it began with a 2 or a 3 He's been on Jim's r/c Boat Dock, so if the email and phone don't work contact him from Jim's if you're a member.
I looked up the Echo PE2000 and found out it is about 21cc.May not be a good candidate for an r/c boat engine to get any speed out of.Most boat engines are in the 25 to 30 cc range.
Probably would made a good air cooled engine for an airplane or airboat.