96 GTX - Seized?

[KyleW2]

Okay, this 96 GTX has me stumped.

I was able to get it to start two days ago, however the starter sounded weak so I pulled it out and rebuilt it. Put it back in today and it was cranking the engine over just fine but never actually started. Walked away from it for a bit and now it just clicks. Pulled the starter and bench tested it, works fine. So then I tried to spin the engine over by hand (plugs out) and it feels seized which doesn’t make sense to me as it ran 2 days ago and cranked fine earlier today.

Any ideas on what else to check? Planning to pull the pump I guess but even that doesn’t make sense. Thanks in advance for any ideas.

Edit: pulled pump and pump is fine. Man, this sucks.

 

[SIMPLEARKANSAN]

Starter solenoid. Jump it with a screwdriver and see if engine turns over.

 

[KyleW2]

Starter solenoid. Jump it with a screwdriver and see if engine turns over.

Should have added I tried that before pulling the starter out again

Took the head off and there was a small chunk of metal on top of one of the pistons. No idea where it’s from but this engine is done. Frustrating as it had 140 psi in each hole.

Now to decide if it’s rebuild time or sell the ski as it sits.

 

[etemplet]

I'd pull the cylinders and have a look.

 

[SIMPLEARKANSAN]

Doesn’t cost anything to pull the cylinders. Maybe not as bad as you think. You have a pic of the top of your pistons?

 

[KyleW2]

Don't have a picture, I'll get one in a few days. I rebolted the head back down just to keep any water out.

The other day it would fire real briefly and then die again (choking or giving it a little gas killed it immediately). I’m thinking something was wrong and then the short amount of time I ran it (maybe 10 seconds?) did it in.

Quick background is I just went through the entire fuel and oil system, rebuilt raves and all that.

Good news is I have another ski coming home with me this weekend (one owner 99 GTX RFI). Bad news is it’ll get put on the waiting list until this one is out of the way

 

[SIMPLEARKANSAN]

Check your rotary gear. Pull the rotary shaft and inspect for brass. Also make sure the rotary valve isn't bent.

 

[TheGTIjetguy]

Go ahead and pull the airbox off to take a look.
When reinstalling my carbs, I didn’t loctite the two bolts that hold the airbox to the carb and they got sucked into the bottom end bending the rotory valve in the process.
The screws can jam in the counterweight on the crank and “seize” the engine.
A couple minutes with a borescope and flexible pickup tool and the bolts were out, a new rotory valve and cover, and it has about 25 trouble free hours since.
My recommendation, try to resolve it with as little disassembly as possible. A small mark on the crown of the piston or the inside of the head from the piece you mentioned shouldn’t be a problem at all. When you get it rotating, you can check the cylinders from the intake ports up for any grooves and scratches.
If all else fails, pull the cylinders and check for broken rings or a piston pin retainer that worked its way out. Best of luck!

 

[KyleW2]

Hadn’t thought about using a borescope - great idea! I’ll go rent one this week. Just need someone to buy my RX so I can put more money in the Gtx!

 

[etemplet]

Forget renting a bore scope. These things work fantastic. I have a different model but it does the job when I need it. This one is $40.00

Borescope

 

[Bryan9812]

Possibly a bad stator