[2000Z272]

I have a 2000 Z272 Shabah with a 7.4L (454) MPI Merc and a Bravo One drive.

I had the boat running on muffs in my driveway without any issues before I changed out the gear oil last Thursday night so I could take it out for the first time this season on Friday. I burnt out the seawater impeller just after putting it into the water. The high temp alarm sounded while I was tying the boat off to the dock - so I hopped in to see the temperature just a little above 250. I shut it down and figured I would let it sit for 10 minutes before I put it back on the trailer.

10 minutes later the boat wouldn't start even though the temperature was back down around 160. When I turned the key, it just made a dull thud/clank noise, as if the batteries weren't charged enough to turn it over. So I got a jumper box - only to hear the same noise two more times. The third time resulted in the thud noise, followed by the popping on the starter drive and that beautifully expensive, high pitched free winding noise.

So, I rebuilt the seawater pump, installed a new starter (worst experience of my entire life), new batteries and I still get the thud noise.

Has anyone ever gotten hydro-lock? Today I'm going to pull all the spark plugs and see if I can get the drive pulley to spin with a socket.

Here's another dimension - my shifter is now hard to move, whether it be from neautral to forward or neutral to reverse. I don't remember moving the shifter back and forth, but I can see it plausible if I couldnt get the starter to kick the engine over - thinking maybe the safety switch on the shifter was messed up.

Would it be possible to have the drive locked between neutral and forward/reverse to cause it to bind everything up?

Sorry for the novel - any help or info on what may be wrong.

[300sflyer]

You might want to pull the drive off and see if the motor will then turn over. If it does, you know where the problem lies.

Keep us posted.

[WetWilly]

Hi 2000Z272, sorry to hear about your troubles!

Now it just so happens that we just had another member who had a similar experience (click here) and according to him, it hydro-locked. It's believed that with the seawater pump out and no water to the exhaust manifolds, it burned out the exhaust baffles and allowed water back up, hydro-locking the motor.

You're on the right tract, remove the plugs and see it you can turn it over by hand. If you do find any water in the cylinders, check the baffles, they probably need replacing too.

Now if there isn't any water, then your next option is as 300sflyer suggested with pulling the bravo off and going from there...

Good luck,
WetWilly

[2000Z272]

Hydro-locked it was and more troubles - but I'm getting close to the end of the tunnel.

I pulled all the spark plugs today to find water in EVERY cylinder - more water in the rear cylinders than those in the front. With the plugs out I bumped the starter and it started blowing all the water out - then it became obvious that I ruined the new starter when I tried to start it up yesterday when it was hydro-locked.

So, another trip to the marina to get a new starter, which was under warranty, and another 3 hours to switch it out since I had to pull the alternator, water pump, intake pump hoses, and starboard battery out again - and then reassemble.

I bumped the starter lightly and it fired right up, no odd noises, vibrations, or smells. It all works fine - question remains - how did the whole engine fill with water? I do not have thru-hull exhaust nor was the stern exposed to any serious waves or submersion that would cause water to flow in.

Sounds like the baffles - which I will check tomorrow and let everyone know.

[2000Z272]

I pulled the elbows this morning to find what appears to be a pretty weathered water shutter - see attached.

Is it possible that this could be the root of the problem? Are the shutters supposed to be drooping this much?

[WetWilly]

That is one wasted water shutter! It was probably pretty tired already so when the water pump went out, the exhaust super heated it and it completely drooped and gulp, in came the water!

[2000Z272]

After 28 hours of working on the boat, 2 starters, a water pump repair kit, gear oil change out, engine oil change out, new fuel filter, new air filter, 2 new batteries, and 2 new water shutters - she was back to herself last night for a two hour run.

The water shutters were apparently the sole cause behind the hydro-lock. Thankfully, I did not have a cracked head or manifold from the over heating.

I cannot stress enough how important it is to maintain the impeller. An $18 part caused a lot of pain and over $450 in parts. Relatively inexpensive to the $1,500 estimate I received from two mechanics.

Attached is a picture of what a new water shutter looks like and what it looks like installed - prior to cleaning out the bilge. I also attached a phone camera pic of my lady sitting at the end of my dock after her run last night.

[300sflyer]

Glad you found the problem and got it up and running! I know for myself, there is a certain level of satisfaction when I do something myself and save money doing so. While it did cost a few $ in repair parts, you now know the job is done right, and you are still further ahead than paying a repair shop.

One last comment: Was the impeller you put in an OEM one? If not, you may want to look here. I was kind of shocked reading it myself...


Problem with non-OEM water pump impellers

[2000Z272]

No, I used a Sierra kit. I asked my mechanic about that before I bought it and he said that is all he uses - just make sure to completely grease all the fins and housing with petroleum jelly so it is lubricated before fully primed.

My previous impeller was an OEM and would keep the engine around 175 at WOT, this one keeps it around 150-155.

But you never know, I'll take it out in a few weeks to see how it's holding up.

Thanks for the heads up.