Should I roll the dice?

[747AMT]

Good morning everyone,
Too make a long story short I agreed to go in, at no cost other than repairs I could accomplish, on a 2005 GTI 718 that my friend had had bought at the beginning of last summer. Seeing as how no boat owner tells the truth when selling, it quit on him the second run out on the lake. He took it to a shop the guy told him it's not even worth messing with and to just go buy a new one. That is what he did. He's not interested in putting any more money in it and I'm not out the purchase price.
I took the jet pump out yesterday. The bearings got so hot it melted the housing. Obviously from lack of oil. So I ordered a new housing assembly as well as a new impeller. It was beat up pretty bad but had little impact damage.
Now for my question: with the massive amount of experience on here, what damage can be done to the engine from an impeller seizure due to lack of lube in the jet pump. I'm trying to decide what else I need to start tearing apart to inspect.

 

[jts32]

If the motor spins free, feels smooth, and has good compression, I would just go through the normal maintenance that it probably has not had in many years. Carb rebuild, plugs, oil filter, PTO greased, and verify it's the correct oil.

 

[747AMT]

That's what I'm getting ready to check now. I can't spin the pto by hand. I can move it I just can't bring it over top dead center which is probably a good thing. I'm going to take the plugs out of it see if I can hear any bad noises when I spin the pto.

 

[747AMT]

I can turn it with the PTO and the plugs in. I just had to get some of the grease off. Once I rotated a few times it got a little easier to turn. I did spray fogging oil down the cylinders before I started trying to turn it and then put the plugs back in. I'm no two-stroke expert so is there anything I should know about doing a compression test I'm one of these as opposed to a 4 stroke.

 

[jts32]

Fully charged battery, plug wires grounded to rear ebox, fuel off, hold throttle wide open when cranking. 150 psi is perfect compression

 

[mikidymac]

Once you determine the compression there are some maintenance items you must do that are specific to the Seadoo's but we will help you with that.

The 2005 GTI 720 is a great all around reliable sik. Even with all my skis it is still my wife's favorite.

 

[747AMT]

I appreciate all the help I can get.
Hopefully I'll get the compression check done Sunday. I need to go supervise an Eagle Scout project tonight and tomorrow. If it does end up needing cylinders for the cost I'm pretty sure I would be just better dropping a whole engine in it, wouldn't I? And why do engine rebuilders not accept SBT engines for cores? Anyone know?

 

[mikidymac]

You are close enough to them shipping shouldn't be bad to SBT. You can get a complete short block with warranty from them.

Engine builders don't take them because they weld the cranks and they can't be easily rebuilt. SBT also sometimes use repaired cases and cylinders that some rebuilders don't like too.

 

[747AMT]

Ok just finished the compression test. Front cylinder holding 135; rear cylinder holding 130. I'm thinking put a new jet pump, drain the gas, rebuild the carb, new fuel filter grease the PTO and see what happens. ....what do all think?

 

[noviceskier]

Ok just finished the compression test. Front cylinder holding 135; rear cylinder holding 130. I'm thinking put a new jet pump, drain the gas, rebuild the carb, new fuel filter grease the PTO and see what happens. ....what do all think?

Top-end refresh coming soon

 

[jts32]

Ok just finished the compression test. Front cylinder holding 135; rear cylinder holding 130. I'm thinking put a new jet pump, drain the gas, rebuild the carb, new fuel filter grease the PTO and see what happens. ....what do all think?

I would also replace the in line oil filter and verify you're running the correct oil, no blue or green. 130/135 psi isn't great, but you should be able to get a couple years of fun before having to rebuild.

 

[noviceskier]

I would also replace the in line oil filter and verify you're running the correct oil, no blue or green. 130/135 psi isn't great, but you should be able to get a couple years of fun before having to rebuild.

Is the 5 psi difference something that could cause issue later down the road?

 

[747AMT]

Ok great I think I'll go that route first and work from there. What oil do you all recommend?

 

[jts32]

Is the 5 psi difference something that could cause issue later down the road?

I would say 5psi difference isn't ideal, but ok. More than 5psi and you probably have a problem with a piston, rings, or bore.

 

[noviceskier]

I would say 5psi difference isn't ideal, but ok. More than 5psi and you probably have a problem with a pistin, rings, or bore.

Agreed.

Top-end refreshment isn't terribly scary for first timers though. When you look into the long run it's always gonna be "what if" and "since I'm this far." Just something to keep in the notebook for troubleshooting later down the road.

 

[jts32]

Ok great I think I'll go that route first and work from there. What oil do you all recommend?

You can use any API-TC rated oil. I use Mystik sea & snow in my 720 skis because it's readily available locally and only $18 a gallon.

 

[noviceskier]

You can use any API-TC rated oil. I use Mystik sea & snow in my 720 skis because it's readily available locally and only $18 a gallon.

Yeah I got mineral oil for my 717 wasn't too bad only a couple more bucks than what you recommended.