I brought a 1997 sea ray 370 sedan...

[AQUALICIOUS]

I brought a 1997 sea ray 370 sedan bridge with the starboard engine locked up.. It does have water in the oil.. The person I brought it from purchased it just as I did 6 months ago..We are starting to take the top and heads off this weekend.. It has 7.4L MPI engine..  any advice before we go into it are anything we should be aware of??. we are taking it apart in the boat just incase its a head gasket..Thanks

[wingless]

Welcome to the forum.

The likely problem source is exhaust corrosion. There is LOTS of online information. Here is an example:

https://www.boatus.com/seaworthy/swbtob.asp

The exhaust manifold, riser and elbow are all jacketed, with the hot exhaust gasses traveling through the center passage and ray water (salt water) pumped through the exterior jacket, for cooling and noise control.

The salt water corroded the cast iron exhaust, providing a 3-4 year life before requiring periodic replacement.

Unbolt and inspect the cast iron exhaust part and inspect. Post images.

Another possibility is there were periods when Sea Ray used log mufflers instead of lift mufflers. The log mufflers were susceptible to trailing wake water injection. If log muffler, upgrade to lift muffler.

If the engine seized, then a rebuild or replacement is required. If exhaust corrosion failure, then the other engine is probably bad (but not failed) too.

[AQUALICIOUS]

Thank you wingless for the input and advice. yes it has lift mufflers on it now.. both engines have just over 700 hrs on them. we are going to start this afternoon to taking apart.. Ill make sure I check riser exhaust as well.. we are hoping to take top off and get the engine to turn..thanks

[AQUALICIOUS]

Wingless also thanks for that link it was very helpful on what to inspect. ill keep a update here on how all goes..

[AQUALICIOUS]

Ok went to work on engine today.. Now I am looking for a engine 7.hL mph 1997. looks like we are going to have to replace.. anyone have one or know of somewhere reasonable to pick up with the heads on?..thanks

[AQUALICIOUS]

oops 7.4L

[AQUALICIOUS]

Looking for..

[wingless]

What is your location?

Was it an exhaust corrosion failure?

Isn’t it just a short block that is required?

[wingless]

The heads and other parts are not difficult to remove and reinstall.

If the heads are bad then just get a long block.

[AQUALICIOUS]

Im in Myrtle Beach SC. We took the cap off the valve cover and stuck our fingers in and something is broke. you can move something around and feels like 2 pieces like a rock arm broke or something so we are figuring maybe a valve dropped and the motor would have to come out anyway.. thanks

[wingless]

Okay.

On my 454 MAG MPI Horizon engines, in my 2000 380DA, the intake / exhaust manifolds and the heads all can be removed w/ the engines in place.

A short or a long block should restore the boat.

There are LOTS of qualified sources in the Fort Lauderdale area. The same should be applicable to your area.

Determine what caused the failure to protect the other engine and prevent recurrence on this engine.

[PETERW]

If the engine is hydro locked you probably have bent rods etc. and a lot of rust inside the engine etc. so the engine is toast get a long block. If it dropped a valve and the pieces are jammed up inside the combustion chamber it probably damaged the involved piston. You need to pull the heads to see what happened. Once you get the heads and exhaust manifolds off pulling the block is relatively easy because you can get at everything. Good luck

[AQUALICIOUS]

PETERW
Thanks for your response. We are now looking for a 7.4L MPI long block or a drop in now.. We decide not to take apart cause we have to replace it all but we may still take apart this week.. We are not having luck on finding a MPI long block at the moment. thanks

[cbruck]

You might try Michigan Motors or PPT for a long block. I thought I needed an 8.1L and did quite a bit of research and they ended up at the top of my list. Personally I would go for a new vs reman as depending how good the shop is, you could have problems with a reman. Look at the warranties on each.

[AQUALICIOUS]

Thanks Cbruck. ill check them out..

[Drago]

MM has been my go to for awhile. They dont have everything but they are quick to deliver what they have

[270SDASE]

If you’re doing all this work, you should consider new risers and manifolds. If the boat has been in salt water - difinitely! If fresh water, depends on age of boat and winterizing technique.