Buying a 1973 Trihull!!!

[saxrulez]

I'm buying this boat this weekend. It has been meticulously maintained by the previous owner who has had it for ~35 years now. Floor, stringers, and transom are solid! The interior is in great shape and the engine seems to run fine.

Its a GM motor, owner is unsure of the size and I haven't gotten to check it out yet, any ideas exactly what engine this would be?

Also what kind of speed can I expect out of this boat?
16' Trihull
120hp I/O Mercruiser Outdrive

 

[ispaydeu]

Re: 1973 Trihull 120hp I/O Mirro Craft?

Re: 1973 Trihull 120hp I/O Mirro Craft?

I believe 120 HP for that year range would probably be the GM 153 Cu In (2.5L) its a 4 cylinder.

 

[CATransplant]

Re: Buying a 1973 Trihull!!!

Probably in the mid-30s as far as speed goes. In rough water, you won't enjoy going that fast. Bam...Bam...Bam...Bam!

 

[fishrdan]

Re: Buying a 1973 Trihull!!!

I had a 140 Mercruiser (big brother of your 120) in my ol' 16.5' 72 SeaSwirl trihull and it would do mid thirties with a 19P prop. The boat was very stable and had lots of room, the only thing I didn't like about the boat was the pounding in 2-3' waves.That boat would handle some really rough water if trimmed properly though. I rode out some 6-7' waves once and lived to tell the tale, but I wouldn't suggest doing that...

I'd check is the fuel tank as my 72 had a steel fuel tank that was rusting and shedding particles into the fuel pump and plugging it up. Pop the fuel filter off the top of the fuel pump and see how it looks. Better than that, go over to the I/O forum and see what you should do before taking the boat out for the first time. There are lots of things to check/replace if the boat has not been run for a while, or should I say, things you need to look at since this boat is new to you.

Have fun!

 

[saxrulez]

Re: Buying a 1973 Trihull!!!

I live about 2 miles away from a lake here so that is where it will be primarily used. Its a really small lake, only chop you ever really get is from other boater's wakes. Its big enough to comfortably ski/wakeboard and that's about it, some smaller areas jut off where I will spend a lot of time fishing.

Should it be ok for pulling up wakeboarders/skiiers(2 skis)?

The stuff replaced within the past 48 months:
Trailer [Caukins brand with spare]: New wheels and tires, lights, Bearing Buddies
Full Cover VGC
Upholstery and carpet
Prop trued and balanced
Starter rebuilt
Trim motor rebuilt
Stainless steel braided Hydraulic lines
New ignition switch
Battery replaced [March 2009]
Shift cable replaced
I/O bellows replaced
Ethanol-proof fuel tank
Water pump impeller
Gimbal lubed
Outdrive pressure tested

So thats about where I'm starting

 

[fishrdan]

Re: Buying a 1973 Trihull!!!

Wow, looks like you are getting a good one as the maintenance has been kept up. I've pulled up guys on a single ski with my old boat, so it's possible, just have to try it and see.

What is "ethanol-proof fuel tank"? Dumping some Stabil in the fuel, or coating the inside of the tank with a sealer like Kreem?

Also, the impeller should be replaced every 2 years or so as it will take a "set" from sitting in one position, it's one of those basic maintenance items. You might want to find out exactly when in the 48 months this was replaced as it could be coming up on the time you need to replace it.