1995 SEADOO GTX 657x STOPS RUNNING AS SOON AS IT ENTERS THE WATER

[aerovette99]

Hello...
I just replaced my engine and it runs beautifully at my house. I start it, hook up the hose and run it for a couple of minutes. it starts right up with no issues.
20 minutes later, while I top off the tank with about 2 gallons of 93, it fires right up. I run it for 20 seconds or so.
As soon as I get to the lake, I fire it up, it instantly starts and no issues... As soon as I put it in the water, it starts, then instantly dies and will only crank, but will not fire.
This happened last week.
After I went home,I pulled the plugs, cooked them with my torch just in case they were fouled (although it doesn't look like it).
I sprayed a quick spray of starter fluid into the carb and it fired right up.
Again, started it up with the hose for 5-6 minutes with the hose and it started instantly and ran fine. I did this each day this past week and it fired immediately each time with no trouble.
Fired it up at the lake just before launching, with no issue. I shut it off after 20 seconds. Dropped it in the water and then fired it up. It started for a second then refused to fire after the initial start. It wouldn't even fire with starter fluid
For the rest of the time, it would only crank but not fire.
Either this ski is afraid of the lake or I hooked up one of the hoses wrong is all I can think.
i notice the line going to the fitting on the top of the engine has liquid in it. WHAT CAN I BE DOING WRONG??
Also,
I removed the spark plug to see if water is entering the combustion chamber. I ground one wire to the grounding block and leave the other wire attached to the spark plug and crank the engine, but no liquid comes out or spray, just strong compression. I did this for each plug hole.
Please advise...

 

[Coastiejoe]

The only real difference from out of water to in water is load. But before we get into that, a few things to note.

Running time on a hose should be MAX two minutes and most say that is to long. The fitting on the ski for the hose is a "FLUSH" access point. The water runs backwards and pushes out anything that may have gotten in the cooling lines while running the ski on the lake/ocean/wherever. SO, the cooling is poor at best. Further, the carbon seal needs to be cooled when the shaft is turning, and the shaft is turning anytime the engine is cranking or running. It can run dry for a short period, but not designed for that reason.

Starting fluid is a bad thing for two-strokes. No oil is being supplied to the engine when it runs on either/starting fluid. I know you are doing it for short periods, just informing you if you didn't know.

SO,, it basically dies with a load. Though i can't think of a reason, I suppose a hose routed to a wrong location could cause issues. But I think if it was only putting water into the engine. I think the impeller could care less as it is not s positive displacement pump. The impeller basically throws water into the line. I bet if you plug the line entirely it would not put any additional load on the engine/impeller. So if we exclude a hose issue, I believe this brings us back to the load on the engine via the impeller.

I would do a compression test as it will help to determine a few things. 1), what the compression is. 2), a potential timing concern. If the compression is excellent, (yes I know it is a new/replaced engine, but still worth doing the test), then we need to look at the timing of the Rave valves and if your are getting enough fuel.

 

[aerovette99]

Thanks Joe for your excellent insight.
I really appreciate it.
Let's go a step farther as i have some updated info.
I removed the plugs and dried them with my map torch. After trying for a moment or two, the motor started (smoked like crazy), and now it runs perfectly again (it's on my trailer back at the house).
I started the engine and let it run for 20-30 seconds in hearing what you stated in your post. It ran and revved fine again. When you said it was at a "LOAD", I will admit that I didn't have the ski in neutral so it would have been a forward load (You pull the handle out halfway for neutral). The guy told me 150 lbs per cylinder, but when I took my OLD compression tester (basically a rubber piece that you push and hold into the spark plug hole, I was at about 125 per. Now this tester is 25 years old and I may not have held it perfectly so that figure might be a little higher, but the least I got was around 123 lbs per.
Now I didn't have any water hooked up to it at all. Just very quickly after it finally started. MASSIVE smoke comes out of the tail, unlike my 1997 GTX with the 787, when I got it started. I did load the ski up with oil before I went out, but I wouldn't think that too much oil in the reservoir would equate to hard starting. Why would I have such fouling once I got into the water though??
I'm baffled!!

Thanks again for your help
Best Regards
Dave
P.S. I gave a thumbs up but a thumbs down popped up after I gave it so I took it away so I didn't give you a bad response and look like a jerk.

The only real difference from out of water to in water is load. But before we get into that, a few things to note.

Running time on a hose should be MAX two minutes and most say that is to long. The fitting on the ski for the hose is a "FLUSH" access point. The water runs backwards and pushes out anything that may have gotten in the cooling lines while running the ski on the lake/ocean/wherever. SO, the cooling is poor at best. Further, the carbon seal needs to be cooled when the shaft is turning, and the shaft is turning anytime the engine is cranking or running. It can run dry for a short period, but not designed for that reason.

Starting fluid is a bad thing for two-strokes. No oil is being supplied to the engine when it runs on either/starting fluid. I know you are doing it for short periods, just informing you if you didn't know.

SO,, it basically dies with a load. Though i can't think of a reason, I suppose a hose routed to a wrong location could cause issues. But I think if it was only putting water into the engine. I think the impeller could care less as it is not s positive displacement pump. The impeller basically throws water into the line. I bet if you plug the line entirely it would not put any additional load on the engine/impeller. So if we exclude a hose issue, I believe this brings us back to the load on the engine via the impeller.

I would do a compression test as it will help to determine a few things. 1), what the compression is. 2), a potential timing concern. If the compression is excellent, (yes I know it is a new/replaced engine, but still worth doing the test), then we need to look at the timing of the Rave valves and if your are getting enough fuel.

 

[Coastiejoe]

For some reason it sounds like you are getting more oil than you should. Again, If the crank seal is bad, that is how the oil is getting into the engine. We have some very knowledgable 2-stroke guys here that can help you better than me, but i have a good grasp of the basics. There is no such thing as neutral on boats with jet drives. The drive shaft is directly attached to the engine. So when the engine is turning the drive shaft is turning. Further, if the drive shaft is turning the impeller is turning. Anytime the impeller is turning it is moving water. There is your "load". [MENTION=31048]LouDoo[/MENTION], additional insight?

As far as the thumbs up thing goes, it goes to a thumbs down so you can remove the thumbs up. So if you click the thumbs up and then hit send, it will give me a thumbs up.

 

[aerovette99]

For some reason it sounds like you are getting more oil than you should. Again, If the crank seal is bad, that is how the oil is getting into the engine. We have some very knowledgable 2-stroke guys here that can help you better than me, but i have a good grasp of the basics. There is no such thing as neutral on boats with jet drives. The drive shaft is directly attached to the engine. So when the engine is turning the drive shaft is turning. Further, if the drive shaft is turning the impeller is turning. Anytime the impeller is turning it is moving water. There is your "load". [MENTION=31048]LouDoo[/MENTION], additional insight?

As far as the thumbs up thing goes, it goes to a thumbs down so you can remove the thumbs up. So if you click the thumbs up and then hit send, it will give me a thumbs up.

Ahh. Ok. It does have a lever that has F, N, & R. This activates a piece in the rear so I assumed that it stopped the "LOAD" at neutral, when I guess it just diverts the water.
I'm bummed. I just can't seem to win with this one.
Thank you for taking the time to help

 

[Coastiejoe]

I'm concerned about the compression. With lower compression the engine can do exactly what you are describing. I suggest getting a quality tester to see where the compression is. At 120 the engine is in need of a rebuild. At 125 it will run but not great...

 

[Mike99]

I second the concern about your compression. Borrow a threaded compression tester from a local auto parts store. Make sure you have a fully charged battery (don't put it on a charger while it is hooked up to the ski). Cold engine, pull both plugs, wide open throttle...

Mike

 

[aerovette99]

OK.. It has 145 in each cylinder. Finally found a real tester.
I rebuilt the carbs completely and found one with a bit of mud in it. I completely rebuilt them with new gaskets, o-rings, needle and seat, etc...
Blew out every orafice with pressure carb cleaner, then did it again. Removed both jets and all 4 needles and cleaned and inspected them, then replaced them. I opened the lower needles to 1 1/4 turn out and the higher needles to 1/4 turn out. Reinstalled the carb and it fires right up at home on the trailer, but as soon as I try starting it IN THE WATER, it just wont fire. The great guy that sold the engine to me (99xx) is a little baffled also. His engine is fine. Overhauling a carburetor is not too difficult so I'm at a loss.
It's a bummer because I really want to go out with my son. We have a 97 GTX which runs great (takes forever to start but runs great once it starts), but the 95 (657x) just can't seem to get it together once it is in the water.

 

[CReynoldsMIZ]

Sounds like it could be idling too low. Does this model have a Tachometer? I would try and turn up the idle screw and see if that helps.

 

[aerovette99]

Thanks CReynolds!!! It does NOT have a tach, but it idles very high when out of the water, but I could definitely try that.
When I tried it this weekend, it sounded like it WANTED to try to fire, but refused. I tried to start it out of the water, it started, but as soon as it touched the water it died and, again, tried to start, but refused to turn over. It's either afraid of water or the extra force on the drive is too much. What do you hook a tach up to on these? I have one that has clips.

 

[Kenneth Foster]

my 94 xp 717 is doing the same thing. mine is leaking water out of the pipe that meets manifold. slowed the leak down by tightening it and it runs in water now.

 

[LouDoo]

Yep, that could do it, if you have and exhaust leak you have less oxygen.

Lou

 

[aerovette99]

I could replace the exhaust gasket. I just need to pick one up. The screws are definitely tight as I just replaced the engine, but I didn't have a new exhaust gasket.

I replaced the entire kit, needle, seat, diaphragms-orings..used 2 cans of carb cleaner and blew out every orifice, cleaned all jets, checked and cleaned all needles and installed them to 1 1/4 on the low and 1/4 on the high, put the carbs back on and hooked up the hose.
Fired the engine and turned on the water and the ski was running fantastic with incredible acceleration..... Took it to the lake and fired it up for just a few seconds before dropping it in the water...again it ran GREAT!!!
Put the ski in the water and the engine IMMEDIATELY DIED. The water from the hose did not affect the performance, but the added stress from the lake water into the larger hose seems to have an issue.
The engine just cranked and cranked but would not turn over. I removed the spark plug and a BLAST of AIR comes out of each hole, so we didn't take on any water...
I remove the ski from the lake and it fires right up and runs correctly....
I'm at a loss and frustrated as hell..
Any ideas???

 

[LouDoo]

I know you said you just replaced the engine, but for starters lets go back to the basics. Get a current compression reading.

By replacing the engine do you mean with a re-manufactured engine, or a used engine? And who did the work?

Lou

 

[eddie708]

i would check the compression with a different tester.


i had a problem like this with my hx. Had 150psi and would run out of water but not in. turn out to be a bad bearing that took out the pto side crank seal

 

[aerovette99]

It was a used engine from a VERY reliable source on these forums. The compression is approx 140 in each cylinder.
I installed the motor.

 

[john_smith]

Hi Guys,
I am new here. I also have the same issue. I have Seadoo GTI with 717 engine.
I also discovered an exhaust leak that seems to be coming from the exhaust manifold gasket. I had a mechanic that worked on it and he also tested it in the water. The ski stalled and stopped in the water, and he also saw an exhaust leak and water leak. He could not determine where the leaks are coming from, but he thinks it might be under the engine. He did not fix any of the leaks before he tested it in the water, although he knew that there was an exhaust leak.

Anyway he made the following observation and possible conclusion: “It will run if revved up while backing into the lake. But as soon as it is allowed to idle, water that is leaking into cases will immediately foul the spark plugs and it cannot be started until it is pulled out from the water. Most likely the gaskets, and probably cylinders and/or case leaking water into crankshaft under running conditions. Motor will need to be disassembled checking for cracks in aluminum cases, aluminum cylinders and every seal and gasket should be replaced.”

He has experience, but it did not look like he had much evidence for his conclusion. All he saw was that it runs on dry, but once you put it in the water it stops. Sometimes fouling the spark plugs could be hard to determine, especially when you change them once you are out of the lake (did it run again because the spark plugs were changed or because the ski was out of the lake).

So, here is my question: Is it possible that an exhaust leak can cause the issue? I don’t mind changing the exhaust manifold gasket, but If I have bigger issue, I do not know if I want to even start on it…
So, aerovette99, if you replace the exhaust gaskets, and this fixes the issue, maybe I can draw from your experience.

I forgot to mention that both cylinders are 120PSI. It seems low, but I’ve read in other posts that some people with the same compression are still fine. Could that be the problem? It runs fine on dry with garden hose hooked up, and there are no water leaks but only exhaust leak (and only if I revved it up too high for several seconds)

 

[aerovette99]

Hi John,

I guess the exhaust manifold gasket is my next course of action.

Hi Guys,
I am new here. I also have the same issue. I have Seadoo GTI with 717 engine.
I also discovered an exhaust leak that seems to be coming from the exhaust manifold gasket. I had a mechanic that worked on it and he also tested it in the water. The ski stalled and stopped in the water, and he also saw an exhaust leak and water leak. He could not determine where the leaks are coming from, but he thinks it might be under the engine. He did not fix any of the leaks before he tested it in the water, although he knew that there was an exhaust leak.

Anyway he made the following observation and possible conclusion: “It will run if revved up while backing into the lake. But as soon as it is allowed to idle, water that is leaking into cases will immediately foul the spark plugs and it cannot be started until it is pulled out from the water. Most likely the gaskets, and probably cylinders and/or case leaking water into crankshaft under running conditions. Motor will need to be disassembled checking for cracks in aluminum cases, aluminum cylinders and every seal and gasket should be replaced.”

He has experience, but it did not look like he had much evidence for his conclusion. All he saw was that it runs on dry, but once you put it in the water it stops. Sometimes fouling the spark plugs could be hard to determine, especially when you change them once you are out of the lake (did it run again because the spark plugs were changed or because the ski was out of the lake).

So, here is my question: Is it possible that an exhaust leak can cause the issue? I don’t mind changing the exhaust manifold gasket, but If I have bigger issue, I do not know if I want to even start on it…
So, aerovette99, if you replace the exhaust gaskets, and this fixes the issue, maybe I can draw from your experience.

I forgot to mention that both cylinders are 120PSI. It seems low, but I’ve read in other posts that some people with the same compression are still fine. Could that be the problem? It runs fine on dry with garden hose hooked up, and there are no water leaks but only exhaust leak (and only if I revved it up too high for several seconds)

 

[Strizzo]

when you rebuilt the carbs and took everything apart, did you check pop off and reset everything to original settings? i'm curious what your pop off is, it sounds like you're running super rich to the point it can't idle in the water.

 

[aerovette99]

Strizzo,

That is a great question.
I'm not sure what that is or how to do it.
I only did the serious cleaning and rebuild, but read but didn't understand what pop off was.
Any step by step would be appreciated. I just purchased the 95 GTX and it had a bad motor.
I replaced the motor and rebuilt the carbs.
Thank you for responding
Best Regards
Dave

when you rebuilt the carbs and took everything apart, did you check pop off and reset everything to original settings? i'm curious what your pop off is, it sounds like you're running super rich to the point it can't idle in the water.

 

[Strizzo]

the pop off controls the mixture from idle to mid range, and affects how the ski acts when you ride around and then park for a few minutes and try to restart.

you'll need to pull the carbs off again. when you cleaned the carbs, did you pull the needle and seat out before hitting it with carb cleaner? usually that stuff is not good for o-rings. you'll need a pop off tester, which you can build from parts to use a bicycle pump or you can buy a mikuni one off of amazon or osdparts for around 45 bucks. as you add pressure, the needle should "pop" at a certain pressure fairly consistently. this is how you can measure the pressure that the spring and lever put on the needle, which affects your low speed mixture. according to the service manual, the pop off for twin carbs should be between 16 and 21psi. you'll also want to do a leak off check with the covers off to make sure the needle and seat aren't leaking, and then again after you reassemble the carbs to make sure the diaphragms aren't pressing on the lever. once you have this set correctly and the carbs reinstalled, you can fine tune the low speed mixture with the low speed screws, but they need to start at 1 1/8th turn out from closed.

 

[aerovette99]

You are a GOD.

Thank you so much.
I replaced the o-rings when I did carb rebuild. I removed EVERYTHING before i used the carb cleaner.
I pulled Jets, needles o-rings, etc.. prior to.

the pop off controls the mixture from idle to mid range, and affects how the ski acts when you ride around and then park for a few minutes and try to restart.

you'll need to pull the carbs off again. when you cleaned the carbs, did you pull the needle and seat out before hitting it with carb cleaner? usually that stuff is not good for o-rings. you'll need a pop off tester, which you can build from parts to use a bicycle pump or you can buy a mikuni one off of amazon or osdparts for around 45 bucks. as you add pressure, the needle should "pop" at a certain pressure fairly consistently. this is how you can measure the pressure that the spring and lever put on the needle, which affects your low speed mixture. according to the service manual, the pop off for twin carbs should be between 16 and 21psi. you'll also want to do a leak off check with the covers off to make sure the needle and seat aren't leaking, and then again after you reassemble the carbs to make sure the diaphragms aren't pressing on the lever. once you have this set correctly and the carbs reinstalled, you can fine tune the low speed mixture with the low speed screws, but they need to start at 1 1/8th turn out from closed.

 

[john_smith]

when you rebuilt the carbs and took everything apart, did you check pop off and reset everything to original settings? i'm curious what your pop off is, it sounds like you're running super rich to the point it can't idle in the water.

I also had some carb work done on mine, so it will be very interesting to see if the issue is caused by the carbs, the exhaust gasket, the engine or something else…

 

[Strizzo]

I also had some carb work done on mine, so it will be very interesting to see if the issue is caused by the carbs, the exhaust gasket, the engine or something else…

exhaust leak can present like a rich condition, because it starves the engine for oxygen, so even though the engine pulls in the same volume of air with the fuel, there is less oxygen and therefore too much fuel. fix the obvious stuff first, then get down to the smaller stuff.

 

[aerovette99]

I ordered a new gasket set which includes carb base, intake, exhaust, and a bunch of o-rings. I'm going to make a pop off pump and set the pop off to about 25 lbs (haven't touched it as of this writing), replace most everything that doesn't require the head to come off and see where it goes from there. The head gasket should be good since I have decent compression. It doesn't look that hard to replace. I removed the last one ( it was a PITA, but nothing that a few hours can't cure.

It includes (where used): flywheel cover, intake manifold, carb base/mounting plate, exhaust manifold, headpipe & cooling gaskets/o-rings.