Need help urgently - compression on standard RN SJ 1998

[Polish jet pilot]

I am about to spend my savings on a bit beaten RN SJ. My first Yamaha

I tried to search but with little results. I done a compression test at 32degrees Fareinheit and it showed 125 PSI both holes. Seems a bit low to me... need advice cuz if that is low I will try to go down with the price.. by the way the gus wants 2400 USD in Europe (which is cheap for this market).

2 motor mounts are bad, but that is not a huge cost...

Help, help, help...

Andrew

 

[Matt_E]

It should be 150 psi.

But they are both even - that's good.
Are you using a good compression gauge?

 

[ADDict]

Should be around 150 per hole, I think.. Maybe 145. They are both even though so thats a good sign. Check the tester.

 

[meatball]

yea, its probably the gauge, check a known good comp ski and compare

 

[Etheraldreamer]

yep. very unlikely they are both losing the same amount of compression from something.

 

[cattledog]

offer less money just in case you need a top end job, tell him it should be 150 psi and offer less

 

[oxnard111]

offer less money just in case you need a top end job, tell him it should be 150 psi and offer less

my thoughts exactly.

 

[BBYamaha]

I wouldnt be scared of 125 a hole... especailly if they dont come up that often in europe and are usually more expensive..

 

[Polish jet pilot]

Hi all, thanks for your input. I checked 2 other superjetc 2002 (80hrs) and 2006 (50 hrs) and they both showed 125 PSI per hole - they were well maintained. Quite strange, maybe 150 psi per hole is BRAND NEW but maybe even after 20 hrs the ski will have around 125/130 psi?

Anyways, the ski I was looking at did not convince me, I found a pretty one in UK - maybe I should import it.. I will see.. life sucks...

 

[Boris]

Sounds like your gauge is showing low. My 18 year old motor has perfect compression so I doubt 50 hours should have any effect.

 

[Sospikey]

If you already consider importing; Sweden is close by for you. Decent price on this:
http://www.blocket.se/vi/20375843.htm?ca=14_s

 

[cattledog]

Sounds like your gauge is showing low. My 18 year old motor has perfect compression so I doubt 50 hours should have any effect.

its the guage

 

[Idok]

Hi all, thanks for your input. I checked 2 other superjetc 2002 (80hrs) and 2006 (50 hrs) and they both showed 125 PSI per hole - they were well maintained. Quite strange, maybe 150 psi per hole is BRAND NEW but maybe even after 20 hrs the ski will have around 125/130 psi?

Anyways, the ski I was looking at did not convince me, I found a pretty one in UK - maybe I should import it.. I will see.. life sucks...

have you not found anyone to ship you a ski from the US???

 

[Polish jet pilot]

Buying a ski is a nightmare here. A ski from somebody on thsi board would be nice, but the exchange rate right now is killing (up by 50%) and shipping and taxes (depend on the "invoice"/seller buyer agreement for ski).. Thus I need to wait or get something from here or UK (European Union). Life sucks..

Or..

I will get the shi....y looking one (1998) with broken engine mounts and would have to build it - I wanted to avoidd that since I know what a good build costs - no cheap alternatives or you cry afterwards!

Question: how long can oem crank be used on oem motor? How many hours/seasons?

Help me get my first REAL ski!
Regards to all!
Andrew

 

[Waternut]

Don't forget that a bad battery or a battery that isn't fully charged will produce similar results. It's cold and it's winter so you can guarentee that the battery isn't working to it's full potential. Both of my batteries sat for 3 months without getting touched. Neither one would run a bilge pump.

 

[Polish jet pilot]

I had my own charged battery with me for testing - but good that you mention it! And I am still looking for my RN baby..... where are you..??

 

[Sdiddy]

Compression

No matter what anyone tells you I have a Factory Yamaha Service Manual that lists all the specs, torque ect. It lists the 1996 and newer models to have 135 stock compression. I know everyone always says 150 but not true at least in the service manual sold by Yamaha.

 

[Matt_E]

What section or page of the manual lists the compression pressure?
I just tried finding it and could not. It's gotta be there, I just didn't see it.

 

[Cliff]

ive always been told that yamahas have a little lower compression so that they will run on low octane gas like in california.

 

[Polish jet pilot]

This is very good news! 135 psi per hole - I guess even if the gauge is off by some, it would not be off by 25 psi. By 10 psi - could be, it is a cheap ebay gauge, but that means 125psi is not bad at all!

So what you guys think: buy a bit beaten ski, dissassemble it, and build it? If engine seems ok, I would just paint the hull, install footholds, maybe a pipe and head, etc... or try to look for something else? Something in better condition...

Question: is there any way to verify number of hours on a 1996+ Superjet?