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98 GTX Limited something seized, engine will not rotate

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divergary

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Pulled the plugs and attempted to rotate the rear flywheel shaft with an 18 inch pipe wrench, not a budge. Last time I used 90 days ago, flushed engine with water, fogged oil thru carbs while running, shut off water and punched throttle a couple times to clear any remaining water and shut down. Pulled plugs and fogged cylinders and cranked it over a couple revs then parked it in under the shed. Location is about a mile inland from the Gulf of Mexico. I usually run in the gulf but the river inland begins getting brackish by the time I reach the boat ramp. Ran great and no clue there was anything thing wrong. Five years ago my rear piston was seized by heat, according to STB. Replaced the blocks and rebuilt the carbs, jet pump, fuel lines and all hoses. Has run great since. The only things I can think of are: rust built up in the cylinders and the piston rings are rusted to the walls, the jet pump bearing(s) are seized, however I would think I could at least feel the slack in the spines of the drive shaft and something on the crank is seized. I want to avoid pulling the engine so any troubleshooting and ideas appreciated.
 
I have seen Saltwater electrolosis corrosion so bad between the Jetpump's
houseing & wear ring, the impeller got locked as the WR shrunk. Only fix for that is
removal & clean & replace wear-ring. Bills86e
 
I would remove the pump housing and see if the motor turns over. What type of engine do you have in it. Is it Sea-Doo or SBT?
 
type engine

I replaced the original Seadoo short block with a rebuilt SBT engine, same design type. Would you remove the head and inspect first or pull the jet pump and shaft first?
 
If you fogged the jugs... and it was running when you parked it... I'm going to say, the engine is fine. They don't spontaneously die.

As above....

Since you are in salt water... I would say it's the pump. If the seals went bad... and the pump bearings were full (or part filled) with salt water... they sat for a few months, and rusted up solid.

Pull the pump... I bet the engine will turn over. Oh... don't start it unless you remove the drive shaft. If the pump is out.. and the shaft is still in the hull... it can whip, and break the hull, the shaft, and the PTO.
 
seizure

Good advise. The only reason I focused on the engine is because when the original engine seized I did not know it until the next use. I launched into the gulf saltwater for a week. I flushed the engine and rinsed everything daily and fogged engine and oiled cylinders the last day. It was not until a few weeks I discoverd the seized engine. First I was thinking it could be the jet pump because I took good care of the engine. But after pulling the pump, it was the engine. I did not pull the head, I just replaced the block. SBT said the rear cylinder was seized due to running lean. I learned alot about enriching the rear cylinder and monitoring the plugs to be sure I was not running too lean. I did notice the last few times I was cruising around 4500 RPM's that the engine would vary the rpms up or down and I would have to change the throttle position to maintain the speed I wanted. Fuel filter and bowl have been clean. Thanks for the advice. The jet pump is alot easier than an engine replacement.
 
Just to be honest with you I would not have an SBT motor in mine. There is nothing Sea-Doo about it anymore. It is all oversized and everything.
 
Seadoo replacement engine

Recommendations of a replacement engine for my 1998 GTX Limited. I used SBT rebuilt engine 5 years ago. Any idea how much a new engine from Seadoo costs? I pulled the jet pump and it rotated fine. Pulled head and everything looked normal. Something is preventing the engine from rotating since last used in early June. What else to look for?
 
I know you dont want to hear this but your bottom end might be rusted up. Or there is a chance that your started is siezed and stuck in the engauged position. Holding the flywheel from moving.

Good luck buddy.
 
bad news

I would rather have bad news than no news as I dont want this to happen again if there is something I can do to avoid it. I did not think the starter even engaged would prevent the motor from rotating even slightly. I can pull the starter and eliminate another item. I can also pull the carbs and get a look into the block. Eventually i can start removing engine parts and looks for the cause. These are not enjoyable to work on, but at least I have overhauled almost everything once so I know how.
Thanks
 
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