1971 Tri-Sonic Riviera (any other ones out there)?

Cody.atx

Recruit
Joined
Jul 8, 2025
Messages
2
I got a 1971 Tri-Sonic Riviera, Straight 6, Mercruiser 120hp, it needs some engine work like distributor cap and gas tank, and possibly new floor from sitting over the years. I got it from a buddy and with title in my name, I’ve seen like 2-3 of this exact kind out there, not many left. If someone is interested of buying it or needing it for parts, just msg me.

It was registered in 2009 and after that parked for awhile, came from Austin TX, it now lives in north Texas.

If anyone has any information on more about them, I would love to know, going to get this back on the water after 16 years of sitting and make this 54 year old boat run again like new :)
 

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mr 88

Commander
Joined
Nov 3, 2010
Messages
2,232
My guess is it's a 4 cylinder (120hp , as the valve cover states ). The in-line 6s usually were rated at 165hp and up . How many spark plugs are there ?
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
Staff member
Joined
Jul 23, 2011
Messages
50,771
texas has had some cold temperatures over the last 16 years. I would pressure test the water jacket to make sure the block and heads are not cracked. I would remove the manifold and do an acetone test.

a lot of work to get that boat back up to snuff.
 
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