engine runs for about an hour then stalls HELP!!

[dieselski94]

I have a 2000 GTi seadoo with the 718 engine. I can put it in the water run for an hour then it will start to slow down like it is bogging out. I have had this problem for 3 years now with no fix. I have found plenty of people with the same problem but no fix has been found. The first hour it runs great, wide open and quick out of the water. So far I have rebuilt the carb, replaced all grey fuel lines, checked the check valve, checked the fuel selector, replaced the voltage regulator and cleaned the fuel filter. I have no idea where to look. I have a nephew that just bought a gti with the same problem. I have made a video of the seadoo acting up on the water. Ill get it up as soon as I can. Any help will be much appreciated. Thanks.

 

[CReynoldsMIZ]

Check your compression. May be time for a rebuild

 

[LoyolaCub68]

Can you get it restarted once it dies or do you have to wait for it to cool down? Have you pulled the plugs to see what they look like after this happens?

 

[- BiRkS_]

Can you get it restarted once it dies or do you have to wait for it to cool down? Have you pulled the plugs to see what they look like after this happens?

^^ Second that. Also, loosen the gas cap and listen for a sudden release of air. That means your vent(s) in the tank are not working and the tank is under vacuum. If it isn't overheating, I would put money on a faulty tank vent.

 

[Strizzo]

Could also be an exhaust leak choking out the motor after a while. If you pull the seat off and air it out does it run again?

 

[kicker]

Could also be an exhaust leak choking out the motor after a while. If you pull the seat off and air it out does it run again?

That is is good point, just to add to that, if you are missing or have your vent tubing not installed properly that will cause the hull not to "breath" properly. Not exactly sure what it looks like on the GTI but you will have a couple tubes at the front, probably 2 at the back along with the big tube (silencer) that is under the seat. Make sure they are all hooked in properly and reach the bottom of the hull.

They all have an important function to keep the fresh air in there.

 

[dieselski94]

Ok Checked the compression and have 125 on both cylinders, when I had it on the water I did check to see if the tank was venting by removing the cap, no air came from that. Also filled the tank back to full to see if it would make a difference with no luck. I have had the seat off but still does not solve the problems and yes the tube are where they need to be. I don't hear any leaking air coming from the exhaust. When it does die on the water it will start right back up. It still boggs down but the longer it sits in the water the farther it will go running right. It has a new set of plugs and coil also. After starting back up it will run wide open usually for about 2 min then die out again. Very frustration machine.

 

[kicker]

I hate to say it, but it is time for a rebuild. At 125 psi you will not be able to get it to run properly.
Normal should be in the 150 range.
As in post #2 by CR whenever these things at the age they are, don't run right, check the compression first. If the comp is not healthy your just chasing your tail trying to make it run properly.

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[nick.bain]

I'm new here so forgive me. I don't agree with the compression being an issue if this was the case it would never run right. The engine components will basically expand at the same rate so to get an hour or two good running doesn't add up for me. With this said I would recommend looking at electrical components coils, magneto etc check the resistances before the ride and then after compare and diagnose.

Google seadoo jetski manual PDF and download the manual for your craft all specs required for the above mentioned test are listed.

Ps does this ski have dual coils if so when you replaced the coil, did you do both or just one??

 

[Strizzo]

I agree, 125 psi is workable, it could also be excessive tolerance in the rotary valve, which would cause it to idle/ run poorly once warmed up.

What sort of condition is the oiling system in? It kinda sounds like the engine isn't getting correct oil, but is getting some oil. Maybe the cable broke and its staying at idle?

 

[bell99man]

I agree, 125 psi is workable, it could also be excessive tolerance in the rotary valve, which would cause it to idle/ run poorly once warmed up.

What sort of condition is the oiling system in? It kinda sounds like the engine isn't getting correct oil, but is getting some oil. Maybe the cable broke and its staying at idle?

Nope, a broken oil cable fails wide open so it would be 40:1 all the time.

 

[dieselski94]

Ok yesterday I took the engine apart to actually find out that the o rings that separate the head and the jug are leaking. Got to take it and bore the jugs because they have rust in the walls. I also think that 125 is a decent pressure but after taking the engine apart it could be what is causing the problem. (I HOPE), This see doo has only one coil on it. I have check battery voltage before I ran, while I was running, and after it was messing up and it is charging the battery at 13.5. It is getting plenty of oil. Ill Post back after it get the bore finished and put the rebuild kit in. Keep suggesting things cause as my luck would have it this will probably not be the cause.

 

[bell99man]

125 is low and rust is bad. It should stay around 150 until for a while. If you are going to go to that much trouble, I'd look really hard at the bottom as well. If you have rust on the crank it won't last long.

 

[dieselski94]

Ill check the crank this week when I take it completely apart. When I order my parts ill get all new bearings. Couldn't think of going through that much trouble without replacing everything that shows wear on it.

 

[bell99man]

good plan! Let us know how it turns out.

 

[smc0922]

You can't replace all the bearings yourself. You need to get a reman/replacement crank.

 

[Strizzo]

Nope, a broken oil cable fails wide open so it would be 40:1 all the time.

It will if the cable breaks off clean above the guides, but if it frays and hangs up in the guide, it can keep the lever from flipping full open. At least one person on this board has had an engine failure because of it.

 

[bell99man]

Did not think of that. I guess that's why we should do regular maintenance on these things.

 

[donkey]

It will if the cable breaks off clean above the guides, but if it frays and hangs up in the guide, it can keep the lever from flipping full open. At least one person on this board has had an engine failure because of it.

yep! i replaced a cable on a "lake neighbor's" ski sat mornin,cable frayed,stuck,then broke,at half travel.

 

[dieselski94]

Well I got some time to take the jugs off and see what I had going on. The pistons are burnt and one of the rings were stuck. I am going to do a cylinder exchange with sbt engines and rebuild. The crank and rods are fine just have to get that top end fixed. How much water should come out of the back of this gti when it is running? I only get a stream of water about 1ft to 2ft long at wide open and no water when at idle. The holes are at the back of the seat. With the burnt pistons I know that it had to get hot, but I remember having dirt dobbers that stopped up the water lines in the back. Also does the wear ring play a part in pumping water through the engine? I want to get this running but not get it hot again also. Thanks