'97 GTX Hydrolocked

Note: This site contains eBay affiliate links for which SeaDooForum.com may be compensated


New Member
Hi all,
I just joined, hoping to get some Sea-doo advice. My cousin picked up a gently used 1997 GTX last year. When he launched it in the spring, he left out the drain plugs, and a few weeks later found it in the basement story of the boat house.
He removed the plugs and cranked out some of the water. 6 months later, I have a Sea-doo in my shop with a seized engine.... I wonder how that happened?

Long story short, I filled the engine with diesel and left it for a few days. With some light pressure on the crankshaft I was able to get things moving. However, the engine is now hydro locked. I have cranked the engine to remove all of the diesel from the top end, and I also removed the drain plug on the rear left side of the engine. If I put even one spark plug in, it won't crank. Only once did it turn over with the plugs in, and a large volume of water blew out of the exhaust hole.

I removed the boot between the muffler and the exhaust pipe, nothing came out. Is there somewhere else I can try and drain from? My concern is that since it's diesel, it won't just evaporate like gas would. I guess there is also a chance there is water sitting somewhere in the exhaust from the sinking... just a thought.

Would appreciate any advice.

Hi, no, at this point I am just trying to get it to crank over. Have yet to try and get it to fire, as I am trying to get the engine to turn freely. I've been going out a couple of times a day to crank the engine and blow out some more liquid. It's getting better, but still won't crank with plugs in.
You have to pull both spark plugs and cover the cylinders with a rag or something. Even the smallest amount of liquid will prevent the engine from turning over. So let it spin with both spark plugs removed. You could easily have seized connecting rod bearing and not hydrolocked. An engine sitting that long with water in it is going to be crap internally. That said.... the "unlikely" dose happen so nuthing wrong with continuing on your path. I've saved a couple. :) Good Luck !!
These 787 motors can hydro lock themselves with not much liquid in the bottom end. as Etemplet said, you need to get that out and if it will turn over without the plugs in it then it is not seized. Pinch off or disconnect the fuel line so you don’t keep adding more liquids to the system. With both plugs out you have to crank the engine over for a while til virtually no more liquid is coming out of the plug holes. Be careful of the starter! I usually go about 3-4 bursts off about 20-30 seconds and then wait 10+ minutes. It is very easy to cook a starter doing this. If the starter is too hot to leave your hand holding it then it is too hot! I will add the battery charger during these waiting periods as a full battery is also key here!

NEVER try to start a Seadoo with the charger hooked up. Frying your MPEM is very likely from too many amps in the system. Always unplug battery charger before attaching Dess key.

Once you feel that no more liquid is splashing out of the plug holes, I would put plugs back in but only finger snug. Try cranking. If it won’t crank you may have put to much stress on the starter which no longer has the torque to turn it over. Also could be a weak battery. Also could be still more liquid in bottom end.

If it cranks over with plugs in then add the fuel back into it.
I always use marvel mystery oil when Im trying to get a engine unstuck Diesel is ok but doesnt lubricate very well. When your spinning it over with the plugs out pour a bit down the spark plug holes. It will chase the bad stuff out.
Thanks for all the great advice!
There is definitely moisture still in there, but it seems no amount of cranking will get it all out. It is getting better though. For now I have just been cranking it a bit every day to get out a bit more. With the plugs finger tight I did get it to turn over a time or two, so it's close. I will definitely pinch of the fuel, I should have done that first thing.
Appreciate the help.
You can try it with just one plug in, and I've read that the plug wires should be grounded when cranking with the plugs out.
It should run on one cylinder. Then switch and blow out the other one.
Pull the spark plugs, throw a few rags over the top and spin it. I've run batteries down trying to the the liquids out. Good Luck !!!
Heyall, just wanted to close the loop:

The battery that is in this thing is toasted, so I have been using jumper cables to get the engine to crank off a car battery, but I guess the connection was limiting. I found a spare ATV battery and got that installed. This gave it a enough extra grunt to crank the engine over with the plugs in. It fired almost immediately, so I took it out to the hose to give it a run. Gave it a few minutes to clear out all the junk, lots of black water, but it's now running well. I'm going to install new plugs, it has a slight miss at idle, but otherwise I'm happy to say i'm handing it back over to my cousin.
Hopefully all is well for him going forward. But I told him, if he finds it on the bottom of the lake again... just leave it there!

Thanks again, appreciate the help.