Gtx 951

[Christopher and]

Hi all I have gtx limited 951
The problem is it starts perfectly out of water but in water starts then dies. There is no water coming out of the pisser i have blown all the pipes and they are clear. Put new ware ring on. I have put hosepipe on and water coming out of pisser. I have put hosepipe straight to inlet pipe and came out the pisser so no blocked pipes would appreciate your thoughts on this cheers

 

[Grim]

Do a compression test first to see if the motor is still in good enough shape. You need to be above 120ish, and be within about 10% of each other. make sure you use a good guage, you can get one as a rental from the autoparts stores. if you are in the USA.
When you say no water is coming out you are referring to when it is in the water and is running. I can tell you my 98 does take a few seconds (15 or so maybe) for it to start peeing and sometimes it is just a dribble for a few minutes or when I get going good!
Does your high temp alarm work? Have you had it beep at you? From my experience though it wont shut your machine off, it will just keep beeping at you like crazy, someone correct me if I'm wrong there. It may depend on what year you have, newer ones may do that.
Also tell us if it is carbed or RFI/DI. and year please.

 

[Christopher and]

Compression is good. it is the carb version. Year is 2000 doesn't pee at all. yes the alarm works it as only gone off on me one time. Thanks for your reply

 

[Grim]

Ok, you said that when it is on the water hose it pees but when in the water it doesn't. But you also said in the water it starts and dies. So let me ask, in the water and it starts does it die immediately, will it stay running for any duration of time. If so, what do you do to make it die? Have you tinkered with the carbs at all? Does the engine sound like it is revving a little high out of the water? What is the RPM out of the water, it should be around 2800 to 3K. The RPM in the water should be about 1400. RPM

Also what was the compression of each cylinder?

 

[etemplet]

It should tinkle some pee pee. If it is not, you have a problem with the waterflow. You likely have 2 distinct problems with the engine. Compression check first is always a good idea. Strange that the ski "starts" in the water and won't stay running? Generally low compression the ski won't start or is difficult to start. As @Grim asked what happens to make it kill and can you keep it running. Some of us a really gifted at keeping things running and nursing them home. Hopefully you don't have much of a problem.

You could have leaking seats on the carbs. You could have water leaking into the cylinders. 951's are known for having head gasket leaks. Good Luck!!

 

[Christopher and]

Sorry forgot to tell you had the top end rebuild so new pistons and rings compression was 128 and 124 . when i start in on the water it idles at around1500 no water out at all can leave it on tic over for 5 mins or so go to rev up stops and then won't start till it's out the water thanks for your replys

 

[Grim]

Well I believe 135 is the top compression number for the 951, I'm surprised that it isn't higher with a new top end. Was it done correctly? Was the top end broken in or has this issue prevented that from happening?
Has it been sitting for any length of time, when is the last time you rebuilt the carbs?

Can you crank the ski in the water, don't rev it, turn it off and re-crank it?

 

[mikidymac]

Perfect compression for a carbed 951 is 130 psi and on a fresh top end both cylinders should be dead on 130 psi. You should not have a difference of 4-5 psi.
At idle you absolutely should have a little water out of the pisser and as soon as you give it throttle you should get a steady stream. If you don't you either have a blockage or an issue with the pump.