2005 Seadoo Speedster Compression

[RobthraX]

Hi everyone - I'm new to jetboats and am looking to purchase a speedster in the next month. I was going to buy a GTX Limited 230 Ski but think the Jetboat will be more practical for me and my girlfriend.

I have found a 2005 Speedster that is very clean (new seats, non skid decking, etc.) but am concerned about compression. The owner claims the engine has about 60-70 hours on it (not documented formally) and he ran a compression test for me at his house.

Cold compression shows approx 105 for all three cylinders. He suggested that is ok since it was cold and when warm it will read 120-140.

Everything I've read stated it should show closer to 150 cold or warm.

This seems indicative of an issue - curious for any insight or if you think 105 on a cold compression test is ok.

As an aside - those hours seem INCREDIBLY low to me. Not even sure that's possible unless it sat. He said it was his neighbors and he used to take it out on the lake on weekends and just park it in a cove.

I attached a few pics and here are links to a video of the compression test and engine running

video-1648762656.mp4
video-1648762656.mp4 on Egnyte

video-1648761944.mp4
video-1648761944.mp4 on Egnyte

Thanks!!!!

 

[MacSeaDoo]

Ideal boost pressure

Look there.

This is from my 2011 150 255HP.

I can hit 62 mph and reach 8160 RPM early season and late season.

Cold, I am nowhere near 150 psi.

I would say the machine you are looking at is sound from a compression perspective.

 

[sktn77a]

The supercharged engines usually run a lower compression but my 215SC runs between 140 and 150psi (depending on who's measuring it). As long as the cylinders are within ~10 psi of each other, this is usually considered good.

 

[RobthraX]

The supercharged engines usually run a lower compression but my 215SC runs between 140 and 150psi (depending on who's measuring it). As long as the cylinders are within ~10 psi of each other, this is usually considered good.

Thank you. In talking to a boat mechanic over the weekend they said for a 17 year old engine that's probably about right, though it prob needs a new gasket or just have the bolts torqued back down.

 

[MacSeaDoo]

Run the boat. If it reaches reaches upper end of the rpm range and you roughly can hit the expected top speed, you are good.

As mentioned, mine is around 115 PSI cold and I can hit 8K rpm and 60 mph, exactly what the boat test review showed when new.

 

[RobthraX]

Run the boat. If it reaches reaches upper end of the rpm range and you roughly can hit the expected top speed, you are good.

As mentioned, mine is around 115 PSI cold and I can hit 8K rpm and 60 mph, exactly what the boat test review showed when new.

Will do - the seller is back tomorrow and he is willing to take to a mechanic to pull the hours and will have him re-run the test.

 

[ski-d00]

compression test doesn't tell you a whole lot, have them do a leakdown test which will give you a better idea of engine health

 

[4tec hoarder]

If you have a short boating season then the hours could be legit, plug in a CanDooPro and find out. I bought my 2008 Challenger 2 years ago, the seller said he thought it had about 200 hours, I plugged in my CanDooPro and found that it had 113 hours on each engine. Also, the compression can vary based on camshaft timing, there is some adjustment in the cam gear to advance or retard timing which causes the compression to go up or down.