motor weights, too much?

[Snookerd]

The heaviest 4 stroke I'd consider is the 140 Zuke and I think it's a little heavy for an 18. Suggest you send a PM to Snookerd, as he had one with a V-4 2 stroke and his dad has one with a 140 Zuke. I believe he feels it'd ride better with a lighter motor.

Bushwacker is correct. Only motors I would put on an 18SF to have the intended weight for the boat is below 380lbs. My family has the 140 Zuke on their 18SF and it does fine, but it isn't close to being self-bailing.