Re: 1997 Alaskan
That's a big boat and the 2008 18 Foot Alaskan "is" rated for 75 hp for the tiller model. So with the 75 you just might be legal. But hull designs over the years might have changed and even though you have a 2 stroke, because of the extra weight of 4 strokes outboard capacity plates have changed too.
Check out this link off Iboats which also gives the 1997 model a 60hp rating: It may have been the one you were referring to . . .
http://www.iboats.com/Lund_Boats__18V_Alaskan__1997/bp/64b49717r0
The 2008 has a built in gas tank which further distributes the weight away from the back of the boat on a tiller model. Notice the side console model is rated higher because you are sitting in the middle. Some tiller models have the driver, motor, gas and battery all weighted towards the back of the boat.
If your capacity plate is missing (which could be a sign that the previous owners removed it because the 75 was over limit). Someone here might own the same year you have boat and let you know if a 75 2 stroke is legal on that boat. But your best bet is give Lund a call in case you ever swap the outboard out for a 4 stroke.
What you don't want to have happen besides being overpowered is too get in an accident and have a guest or the boat you hit sue you and they find you overpowered the boat.
This is off of their site:
1800 ALASKAN SS & TILLER PREDATOR SPECIFICATIONS
HULL IPS™ (Integrated Power Strake™)
IPS™ CHINE 69.5"
LENGTH 18'9"
BEAM 83"
TRANSOM 20"
FUEL 19-gallon built-in tank
BILGE N/A
LIGHTING Navigational
POWER N/A
OUTBOARD RATING 90 HP (SS)
75 HP (Tiller)
Sorry to sound harsh on my first response but it was because you mentioned you planned to have two little kids on board!
Since you're new to boating absolutely take a boating course over the winter. I like the ones that with the Coast Guard Auxiliary or other qualified instructor gives on a couple of Sat. mornings or eves. I feel it's better than taking it on they web like some do because of the interaction of the other boaters and the instructor. It's cheap and priceless.
My Wife and I had to take the course in NY if we wanted to drive jet ski's that a friend of ours owns. We took the course (my Wife scored a 100 on the test, how scary is that). But I've been boating for 30 years and learned at least a dozen things I was doing wrong all the time. Like I said, the course is priceless.
Do a search here as others have talked about the value of taking a boating course in other threads.
There is also a ton of info from other boaters here in this forum. You can learn a lot about boating by surfing through the threads here.
Good luck.