Sonic started Hydrolocking.....update...opinions
 

Well I started busting starters about 6 months ago. Replaced it and everything seemed to work fine for several months. Thought that the bolts worked their way loose and the case had gotten cockeyed and busted. At Lake Cumberland Poker Run I busted another starter and put her to rest for about 3-4 weeks. I got a new starter about a week ago and went to change it out and removed the starter and notioced the same problems as earlier this season....starter seemed to be busted on the casing. I put the new starter on and fired her up and it had troubled the first time then fired up fine. Walked around out back and noticed some brownish rust water had come out when it kicked over. Took it on a run and noticed no white smoke, engine temp was fine, everything seemed perfect. When I took it to have it winterized the guys pulled the plugs to fog her and realized their was water in 2 cyclinders but still none in the oil. They found the culprit to be ate up risers. I got on here and posted an ad to get some used risers but wound up ordering a new set of manifolds and risers from merc. We also switched out that 30lb beast of a starter for a high torque smaller starter. I am awaiting arrival of the new risers/manifolds (were supposed to arrive today). They are going to install the new parts and run the motor for awhile and swap oil out. I asked them to compression test all the cylinders on that motor (checked other motor and it was water free and exhaust looked like it had been replaced before I bought it). If it compression test ok I am hoping that I caught this earle enough that there is no serious internal damage. My 454's have about 400 hours on them and run great. I was hoping to see double the life out of them. Anyone have any other suggestions on this process. The oil I am using has a high rust coating additive. It sounds like I just lost all my money put aside for new guages this winter though :(

Sonic started Hydrolocking.....update...opinions
 

I had a similar problem, my #3 engine kept breaking starters and hydrolocking. I sent the engine back to the machine shop and the broke it down and found some water in a few of the cylinders. They re assembled the motor and ran it with a set of dry pipes (on the dyno) and the motor was perfect. We put the manifolds on and still no problem, then we put the riser pipes on...PROBLEM. the motor hydrolocked again. We pressure tested the pipes before and they passed but they actually had hair line cracks in the. We sent them in to Hardin marine and had a new set built.......and no problems. The boat ran perfect the rest of the summer and the motor wasnt damaged. The only damage I had was the starter ring and the starter. We checked and rechecked everything and couldnt find the problem until we started the process of elimination. I would have never suspected the risers, they looked new but they had hairline cracks on the welds. The motors are pretty tough just make sure you didnt bend a rod and check your starter ring for missing teeth.

I had one tooth that looked a little funny but like I said we put a brand new high torque starter on it that has never been started. And the water on mine was from the inner circle on the inside of the risers that the pipes slide In to they were rotted all to hell, but I decided to replace manifolds and risers to completely eliminate exhaust issues.

I think you are on the right track. Had a buddy with the same issue and was told over and over by the mechanic it was just the starter. Finally he took the manifold's off and found a crack. replaced and all is fine. It sounds like they are checking all the right stuff to make sure you dont have anymore damage.

Well got the sonic back today finally. After a compression test all cylinders were between 150-160 except one at 135. Doesnt sound horrible and hoping to squeeze some more years out of her. Anyone got any comments on this? Then I took my f250 in to have the oil changes and they said my front end was just about wore out so I had to replace all those components and a new set of Michellin tires. Been an expensive week but I hope everything is running well now.