96 GSX 787 engine compression when carbs and exhaust removed?

[JMAN1]

Hello all,

I have this ski that I flooded on the hose(yeah yeah I know I'm an idiot) the engine was full past the carbs and unfortunately I couldn't work on it for two weeks as I was gone for my job. But when I got back I flipped the Ski upside down, drained the water and then used a combo of wd-40, seafoam, and isopropyl alcohol in it to remove any residual dampness and small amount of rust that may have built up. Today I cranked over the engine with the carbs, spark plugs, and exhaust removed in order to shoot all of that crap out. Then I hooked up a compression tester I borrowed from O'Reilly auto with everything still off and I got; 82 and 75 ish. So.. is it possible that the engine that was a great running rebuild by a shop this past spring actually is completely trashed from having water in it? And if so: how is that possible?

Thanks guys,
Jasper

 

[kmarts]

Can't tell as to why the compression sucks but you let it sit two weeks with water in it, the motors gone... When that happens you only have a few hours to clear it and you have to ride the snot out of it after to try and evaporate any residual moisture.

 

[Jeffspx]

It is very possible. But its not locked up. Thats a start. Id probably try to pull the head and take a look. I'd also question whether you could trust that compression gauge. Id get the head off, see how bad it looks. If its not too bad and the rings arent broken or anything, I'd get it nicely lubed up with some fogging oil or 2 stroke oil and then try to fire it up.

 

[JMAN1]

Can't tell as to why the compression sucks but you let it sit two weeks with water in it, the motors gone... When that happens you only have a few hours to clear it and you have to ride the snot out of it after to try and evaporate any residual moisture.

Can you explain why that is? As soon as I poured all the water out I put 3 different types of oxygen and moisture removing chemicals in theres and turned the motor over by hand until I was sure every MM of the interior was coated in the concoction... now say even if there was rust forming while it sat why would the amount that could have formed be detrimental to the engine? I understand some of the bearings and the cylinder walls becoming slightly scored by the rust after being dissolved by the chemicals. But enough so that the engine would be ruined? I just dont understand.

 

[kmarts]

Can you explain why that is? As soon as I poured all the water out I put 3 different types of oxygen and moisture removing chemicals in theres and turned the motor over by hand until I was sure every MM of the interior was coated in the concoction... now say even if there was rust forming while it sat why would the amount that could have formed be detrimental to the engine? I understand some of the bearings and the cylinder walls becoming slightly scored by the rust after being dissolved by the chemicals. But enough so that the engine would be ruined? I just dont understand.

Rusty bearings = grenade.

Even though everything may be loose, you're on borrowed time. The steel internals have started corroding.

You can clear it out, lube it up, and get it to run... But if it's started to rust its done.

 

[mikidymac]

As said it’s the crank bearings that are on borrowed time now. The rust acts like an abrasive on the bearings and they eventually eat themselves and throw a rod through the cases.

 

[JMAN1]

Alright thanks. So who can tell what it costs on average to have someone rebuild them? Or is it something I could do without a large amount of hours? Works got me pretty tired down.

 

[mikidymac]

You need a new crank. Cheapest and best quality is OEM from Pro Caliber out of Washington.