89 Sonic 28SS
#11
That is a great looking boat. I can't believe it's aged that well.
Couple things:
That's a lot of engine(s) in a little bilge. It's going to be tough to work on at times. Thankfully, even the older Sonics have the rear seat go up with the hatch. However, make sure you spend some time putting your hands on expendable parts while you are investigating the purchase.
-Spark plugs (all of them)
-Starters
-Water Pumps
-Trim Pump solenoids
Also, two particular models in the Sonic line-up are known to have a bit of porpoise.
Those are the 28 & the 35.
This doesn't mean they are poor choices. Just be ready for such.
Porpoise only happens on smooth water. It has to do with the balance of the COG, stern weight, lifting strakes, and most important: notched transom.
Before you purchase, make certain you test drive on smooth water, and that you can trim the boat as such that it will not porpoise.
Almost always, porpoise can be controlled with drive and tab trim adjustment.
There are some other posts about these topics over the years here. I do believe that the 28 is the fewest made model of the Sonic lineup over time. It was phased out sometime in the late 90s in favor of the 26 & 31. It's not much bigger than the 26, and the 31 is a considerable difference.
Couple things:
That's a lot of engine(s) in a little bilge. It's going to be tough to work on at times. Thankfully, even the older Sonics have the rear seat go up with the hatch. However, make sure you spend some time putting your hands on expendable parts while you are investigating the purchase.
-Spark plugs (all of them)
-Starters
-Water Pumps
-Trim Pump solenoids
Also, two particular models in the Sonic line-up are known to have a bit of porpoise.
Those are the 28 & the 35.
This doesn't mean they are poor choices. Just be ready for such.
Porpoise only happens on smooth water. It has to do with the balance of the COG, stern weight, lifting strakes, and most important: notched transom.
Before you purchase, make certain you test drive on smooth water, and that you can trim the boat as such that it will not porpoise.
Almost always, porpoise can be controlled with drive and tab trim adjustment.
There are some other posts about these topics over the years here. I do believe that the 28 is the fewest made model of the Sonic lineup over time. It was phased out sometime in the late 90s in favor of the 26 & 31. It's not much bigger than the 26, and the 31 is a considerable difference.
#13
Banned
Joined: Jul 2011
Posts: 9,594
Likes: 46
From: Ft. Worth TX
I have never seen a 28 in person but IMO twin big blocks in that had to be one stern heavy ride. Probable that would have made the porpoise even worse.
Also as with any Merc I would have checked out gimbal ring wear and play - side to side and up and down along with the hinge pin areas. Also a boat of that age, pull the drives and check engine alignment, look thru at the engine coupler & splines along with all other related transom assembly BS problems that can take place. So many Bravo's have gimbal ring wear thru the swivel shaft area and or the nut has backed off some. Bravo III are even worse with it.
Also as with any Merc I would have checked out gimbal ring wear and play - side to side and up and down along with the hinge pin areas. Also a boat of that age, pull the drives and check engine alignment, look thru at the engine coupler & splines along with all other related transom assembly BS problems that can take place. So many Bravo's have gimbal ring wear thru the swivel shaft area and or the nut has backed off some. Bravo III are even worse with it.
Last edited by BUP; 08-16-2015 at 11:40 AM.





