2000 GTX RFI full rpm's on trailer, MAX 3400 rpm in water, no codes flashing.

[ShadeTreeDad]

Please accept my gratitude for any tips, help, and ideas. 2000 Seadoo GTX RFI Millennium Edition.

This ski has an SBT reman that has run flawlessly for 4 years since professional installation. At the end of last season, plastic reverse cable bushing failed unknowingly and entire ski flooded. Immediately removed from lake, pulled plugs and cleared as much water as possible, but couldn't get a restart. This spring, engine seized. Filled cylinders with mix of kerosene and Marvel Mystery oil overnight. Still stuck. Pulled cylinder head, found rust in cylinders. Cleaned and freed pistons with brute force. Turned extensively with starter. Brown liquid everywhere. Reinstalled everything and got engine to fire and idle. Found and replaced failed rectifier. Installed new spark plugs. Took to water and ran 10-15 minutes. Engine runs smoothly, but won't exceed 3400 rpm. Full RPM on trailer. Brought home, both cylinders comp test 140 psi. Both plugs now wet black and fouled. I have not yet been to dealership, but I've got no "maint" flashing or any flashing red codes happening.

I am a decent shade tree auto hobby mechanic, but I know very little about where to start with this problem. Suggestions please. Thank you.

 

[snikwad003]

If it's full of brown liquid then your crank no doubt rusted and will likely make your motor not good for a core if it comes apart. In my opinion it's time for a rebuild/replace but that is totally separate from the 3400rpm issue.

 

[Cheflen]

Please accept my gratitude for any tips, help, and ideas. 2000 Seadoo GTX RFI Millennium Edition.

This ski has an SBT reman that has run flawlessly for 4 years since professional installation. At the end of last season, plastic reverse cable bushing failed unknowingly and entire ski flooded. Immediately removed from lake, pulled plugs and cleared as much water as possible, but couldn't get a restart. This spring, engine seized. Filled cylinders with mix of kerosene and Marvel Mystery oil overnight. Still stuck. Pulled cylinder head, found rust in cylinders. Cleaned and freed pistons with brute force. Turned extensively with starter. Brown liquid everywhere. Reinstalled everything and got engine to fire and idle. Found and replaced failed rectifier. Installed new spark plugs. Took to water and ran 10-15 minutes. Engine runs smoothly, but won't exceed 3400 rpm. Full RPM on trailer. Brought home, both cylinders comp test 140 psi. Both plugs now wet black and fouled. I have not yet been to dealership, but I've got no "maint" flashing or any flashing red codes happening.

I am a decent shade tree auto hobby mechanic, but I know very little about where to start with this problem. Suggestions please. Thank you.

What's your compression? If it runs good without load but has struggle under load (in the water) it can be low compression

 

[ShadeTreeDad]

If it's full of brown liquid then your crank no doubt rusted and will likely make your motor not good for a core if it comes apart. In my opinion it's time for a rebuild/replace but that is totally separate from the 3400rpm issue.

This is my fear, too. I think I'm willing to cautiously risk it to not have to purchase and install another reman. I poured close to two quarts of kero/oil mix into the thing trying to free it up. It is possible that was the brown liquid. But, I do hear what you are saying.

 

[ShadeTreeDad]

What's your compression? If it runs good without load but has struggle under load (in the water) it can be low compression

Both cylinders compression test at 140 psi.

 

[mikidymac]

Your engine is toasted. You are going to throw the balancer or crank through the cases and not have a core.

 

[ShadeTreeDad]

Your engine is toasted. You are going to throw the balancer or crank through the cases and not have a core.

I've already been down that road. Not interested in going there again. New SBT reman getting ordered this week. Their tech guy said pretty much the same thing. Thanks for your reply.

While I've got you, I have one question I can't find the answer to. Could you direct me to information on how to check fuel pressure on a 787RFI? I have searched without success. I have a test kit, but what fitting is used and where/how does it attach to the system? I've read that I'm looking for 56-60 psi. Many, many thank yous!