Ski only goes 29mph and bogs

[brettk]

I have a 1998 Seadoo GTX Limited here is a list of everything that I have done to it

1.) Rebuilt carbs
2.) Changed all the gas lines
3.) Cleaned the rave valves
4.) New coil
5.) Fixed exhaust leak at the exhaust ring and at the manifold.
6.) Pressure tested the tank
7.) Check the fuel valve
8.) Grounds are all clean
9.) Fuses are all good
10.) serviced the jet pump oil
11.) Wear ring and impeller are in perfect condition
12.) Water pick up is clear

Ski will run good for about 10 minutes on a cold start reaching top RPM and top speed of 60 MPH then begins to bog down only reaching top speed of 29MPH.
After ski is warm it has great hole shot for about 10 seconds and then will bog down.
The ski starts on first push and continues to idle good and runs good up to 29MPH
I think I see some water on my plugs. Could a blown head gasket be my problem?

 

[Dr Honda]

You shouldn't start 2 threads. I'm locking the other.

You need to take the carbs apart again. they aren't right. Also... you may be overheating. Have you checked head temp with an IR gun?

 

[brettk]

Explain to me why it is perfect start great hole shot great mid and top range for the first ten minutes seems that once motor is warmed up problem begins what makes you think the carbs. Would pop off pressure be a factor here? Give me examples why you’re leaning toward carb issues when this exact problem existed prior to rebuild.

 

[JJinSC]

Carb problem could be causing you to run lean which could be causing a lean seize. That is what I believe Dr. Honda was saying.

 

[brettk]

Carbs are good nothing wrong with them I need another suggestion other than carbs

 

[tobytd]

Check compression

 

[brettk]

So tell me what a lean seize is cause I know what seize means and no where in my description did I say my motor seized it runs the whole time but only will get up to 29mph after about 10 min of riding then it bogs but doesn’t die and will continue RUNNING. Please be more specific

 

[brettk]

Just checked compression and they were both at about 130 psi

 

[brettk]

Check compression

Checked compression both cylinders are at about 130 psi

 

[brettk]

Carb problem could be causing you to run lean which could be causing a lean seize. That is what I believe Dr. Honda was saying.

So tell me what a lean seize is cause I know what seize means and no where in my description did I say my motor seized it runs the whole time but only will get up to 29mph after about 10 min of riding then it bogs but doesn’t die and will continue RUNNING. Please be more specific

 

[jjsinaz]

Check your fuel tank vents. The check valves some times get gunked up. After you run for a while, if the check valve isn't letting air into the tank it will build up a vacuum and will not pull enough fuel. An easy way to check if this is the problem is to loosen the gas filler cap and see if it runs better

 

[brettk]

My Reason for leaning towards a bad head gasket is I believe what might be happening is that after the motor warms up there is a small breach in the head gasket at mid range in higher rpm’s I believe it is opening up that break in the head gasket and allowing some water to get into the cylinders causing a foul in the plugs. Now as for the top speed of 29 or 30 miles an hour i’m thinking that add that speed and lower there isn’t enough pressure on the head gasket or water circulation to actually allow the water through the breach in the gasket itself. Does this seem like a possibility?

 

[jjsinaz]

That sounds plausible. Pull the head and take a look. You need to get the water issue fixed before moving on to anything else. These engines don't last long once the internals start to rust and the 951 is especially sensitive and prone to water ingestion issues

 

[brettk]

Thank you very much for your response it confirms some of my suspicions however could you elaborate on what other water issues other than a bad head gasket I might be dealing with

 

[benjilafouine]

These engines are water cooled I presume, same for the muffler. On my 2003 GTI, I lost an engine in 2015 because there was a hole in the muffler and it flooded my engine somehow. Before my engine died, it had some issues (engine was missing). I found the issue too late.

If I had removed the seat and ride with it when it first sounded bizarre, I may have saved my engine but we found the hole in the muffler (a welding point) after the engine was gone and full of water.

Try to ride without the seat on to see if you notice any water leaking somewhere.

Benji.

 

[mikidymac]

Nope, you either have a blown head gasket or you don’t. It isn’t something that opens up at different rpm’s. If you have a blown gasket you will have low compression and the spark plugs and cylinders will be steam cleaned not fouled.

If your ski won’t go over 30 it’s low compression or a carb/fuel issue. Have you checked your reeds?

 

[emspjay]

Does the 1998 Limited have a rectifier like the 1996 GTX? When my 1996 GTX rectifier went bad the ski would run great for about 10 minutes and then start bogging.

 

[benjilafouine]

Just thought of something: last month my ATV started bogging down (a carb model). It would run great for a few minutes then it would bog down if I tried to accelerate. Turned out it was the stator that was dying.

So it could be an electrical problem after all.

 

[R-u-n2it]

It would have to be rich to run good at 1st then once warmed it would be too rich if it was carbs. Never heard anyone ask if genuine Mikuni parts were used to rebuild. My money is on something electrical that gets heat soaked, a ignition coil will react that way, so will a source coil, but if it still holeshots well once hot.... that's the most load on an engine, that's where detonation will eat aluminum. Find someone that has a similar doo and R&R one electrical component at a time and ride, you will know for sure, age old process of elimination. AND be sure to reply with what fixed it so others will have something to go on. Good luck.

 

[brettk]

Thank you for all of your responses I’ll look into it and get back to you guys

 

[brettk]

And yes I used Mikuni parts on the carbs

 

[benjilafouine]

Even then, needle and seat are so easy to mix. Happened to me (or rather to mechanics who rebuilt my carb). Ski was not bogging but the transition between the low and the high was all screwed up.

As for my stator on my ATV, in fact, it was because of the wires coming out of the stator touched metal when the sheath developed a crack. Wires started touching the corner of the starter making sparks and even leaving a dent in the metal casing of the starter. Then the stator gave away. Small problems can become big. So check all your wiring. A simple crack around a wire could be causing your issue.

 

[R-u-n2it]

Did you find the problem yet?

 

[brettk]

No not yet

 

[brettk]

Did you find the problem yet?

No not yet