My buddy went to buy a mint 99' Sonic 26 with 502mpi and trailer for 25,700 on Sunday. We did a compression test and one cylinder was half of the others. Do you think this is in the valves...head job? Or is it rings? Is the boat still a good deal and the owner did say he'd consider a lower offer to leave room to fix it. The boat did porpoise alot and he didnt like that but everything I've been reading looks like its a great boat. Thanks for all the input

Seriously, factor in the cost of a complete rebuild, then add about another 25%. That's for all the crap ya find after you pull the motor apart. There are a ton of great boats out there for reasonable prices. Don't buy a problem unless it's a GREAT deal.



Darrell.

???

I'd have to side with Darrell on the "consider a full rebuild" cost. The motor is 10 years old, there is no need to fix only one cylinder on a motor that has that many hours.

The porpoising could have been from a lack of power out of that cylinder though!!

Knock the cost of a full "stock" rebuild off the price and you've got yourself a deal.

I've put a few posts up about Sonics and porpoising. If you do a search, you will come up with some info. It has to do with the notched transom, and the boat running out of hull once it gets up on plane. It's only a pitfall in smooth water, and you can dial it out once you know the boat.

did your friend end up buying the sonic?

No he passed....really didnt like the way it rode and then the low compression was the clincher. I thought it was a good deal at 25k. He's still looking................