94’ XP Warm Issues

[Spiffy1996]

So got a 94 Seadoo XP with the 657x at the start of the season. Bought it as a fixer upper. It ran on the trailer when I bought it and since then I’ve taken it out a handful of times and figured out more underlying issues and addressed them as I went out more and found them. So far I’ve put in a new battery, new BR8ES plugs gapped at .022, cut the plug wires back and cleaned up the spark plug boots, all new 1/4” fuel lines and vent lines (only line I don’t think I did was the vacuum line that goes from the engine to the carburetor), cleaned fuel selector switch, new exhaust gaskets (manifold and pipe gaskets), and cleaned the carburetor. Now I’m at the point where I can run the ski in the water for about 10-15 minutes and then it will start to bog down, it’ll be able to stay at idle for a minute or two and when you give it gas it’ll just bog during this time then eventually it’ll just stall out and won’t start in the water until it sits for a half hour or so then all is well but it repeats the process all over again. However if it stalls out and I pull it from the water right then and there it will basically start right up on the trailer like there’s no issue. When it’s cold it will fire right up on the trailer and in the water without even needing to choke it and it runs really good for the 10 minutes it does run but always will begin to bog and stall out after 10 minutes or so. I thought maybe it was getting hot as the temperature buzzer had gone on a few times but I took my temp gun and got a reading of 130 degrees on the head right next to the spark plugs right after it stalled out after the 10 minutes of riding. It’s pissing a good stream and the water coming out isn’t any more hot then it is on my Kawasaki STX12F that runs absolutely fine so don’t think it’s a cooling issue. The ski does show 125psi on both cylinders cold which I know isn’t great but considering it starts up just fine cold in the water I didn’t think that compression would be the issue. Spark plugs appear slightly more on the black side vs “toasted marshmallow” but considering it’ll start right up again once cold means I don’t think they’re fouled. Got the idle set to 2100 on trailer and 1500 in water I think? I forget exactly and go figure the last times I took it out the tach started only working when it was above 4,000 go figure. At a loss here, what y’all think? I’m thinking maybe that vacuum line I didn’t replace might be expanding when warm and closing up causing the carbs to not pull in fuel till it cools off and re-expands? Any thoughts or input greatly appreciated!

 

[AKnarrowback]

Double check your rotary valve clearance. One indication of too much RV clearance is an easy start when cold but hard or no start when warm.

Have you been into the carbs yet?

Glad to see another 94 XP here.

 

[AKnarrowback]

Just for fun.

 

[etemplet]

Always do a compression check before troubleshooting anything. Your description sounds a lot like low compression. Rule that out first thing.

I'm just finishing up a 1995 SPX which is pretty much the ski you have. 657X engine and all that. I have a thread here 1995 SPX Resto I just posted more pictures. If you have any questions hit me up. Good Luck !!

 

[AKnarrowback]

Sorry bout that.

I was thinking a few steps ahead.

Do a compression check first no doubt. If the motor isn't healthy chasing other things isn't going to help.

 

[Spiffy1996]

Always do a compression check before troubleshooting anything. Your description sounds a lot like low compression. Rule that out first thing.

I'm just finishing up a 1995 SPX which is pretty much the ski you have. 657X engine and all that. I have a thread here 1995 SPX Resto I just posted more pictures. If you have any questions hit me up. Good Luck !!

Compression is 125 on both on a less than credible tester, not a snap on but I don’t think it’s THAT far off. If it were low compression I’d think I’d have trouble starting cold but the thing will fire right up cold.

 

[etemplet]

Below 120 is what has been often reported as "done." and starting issues on the water. If you have 125psi it is top end time for the engine. I've had serious piston and cylinder damage and recorded 130psi. Good Luck !

 

[AKnarrowback]

Yup, that's getting low on the PSI.

Just a suggestion.

On my 94 I raised my pop off pressure from the 18ish up to 28ish to help clear up the low end operation. I installed a 271000454 impeller and get good all around performance without hitting the rev limiter, top rpm's sit right at 6600 at sea level. The stock impeller in that machine was pitched too high and really made them sluggish on the low end, combine that with the low pop off pressure and I wonder how they ever released them.

 

[Spiffy1996]

Yup, that's getting low on the PSI.

Just a suggestion.

On my 94 I raised my pop off pressure from the 18ish up to 28ish to help clear up the low end operation. I installed a 271000454 impeller and get good all around performance without hitting the rev limiter, top rpm's sit right at 6600 at sea level. The stock impeller in that machine was pitched too high and really made them sluggish on the low end, combine that with the low pop off pressure and I wonder how they ever released them.

So I replaced the vacuum tube from the crank to the carb as I was correct it was the only one I didn’t touch and was still original, took it out today and same old same old except I was able to figure out that once it gets warm it’ll run in the 4K range no problem the second you let it get anywhere above or below 4K rpm it’ll stall and die. Still getting 130 degrees on the heads so I’m guessing I gotta carburetor issue at this point and spark is just as good hot as it is cold. I just don’t get why the temperature thing is playing a part like if it was a carb issue I’d think I’d be seeing issues regardless of temperature?

 

[etemplet]

I think you have a compression issue. Carbs don't generally do that sort of thing.. After the ski warms up they should be pretty consistent good or bad.

 

[AKnarrowback]

Motors run different if they are not fully warmed up. If it's not a high tech computerized system that compensates for everything then it's just a regular carbed motor that is tuned to run with everything at a good running temperature. If the motor is not in good condition then once it is fully warmed up you can have poor running.

 

[Spiffy1996]

Motors run different if they are not fully warmed up. If it's not a high tech computerized system that compensates for everything then it's just a regular carbed motor that is tuned to run with everything at a good running temperature. If the motor is not in good condition then once it is fully warmed up you can have poor running.

That’s crazy cause I’ve always been led to believe it’s the opposite problem with low compression motors and how they will give you all kinds of trouble when cold but once warmed up and the rings expand It will actually improve. I’d just hate to tear the motor down and have the same issues on a fresh rebuild because it was something little and stupid the whole time.

 

[etemplet]

Do you buy any chance had an aftermarket IN LINE fuel filter on that system?? Those bitches cause problems you'll never find till you remove it and throw it away. @mikidymac hooked me up with that wisdom. I will NEVER forget that one !!! Never never never install and in-line filter on these carb skis.... never.

 

[Spiffy1996]

Do you buy any chance had an aftermarket IN LINE fuel filter on that system?? Those bitches cause problems you'll never find till you remove it and throw it away. @mikidymac hooked me up with that wisdom. I will NEVER forget that one !!! Never never never install and in-line filter on these carb skis.... never.

I do actually, just an inline filter, I guess factory it had a water separator or something but that’s all gone and when I ran the new lines I went straight from the tank to the fuel switch to an in-line filter to the carbs. I totally cleaned out the switch when I did the lines also. Maybe I’ll try yanking the filter and seeing what happens then.

 

[etemplet]

Right On !! Ditch it.

 

[AKnarrowback]

The factory water seperator/filter is the best set up. Find one and get it back in the DOO. They are a setup that allows you to clean them out and remove the trapped water. Why anyone adds more filters or removes the stock one makes no sense. I drop the bowls on my DOOs every other ride just to check things and make sure I get the water out .

 

[POPPS]

125 compression will not cut it. As AK said, excessive rotary valve clearance will also cause your symptoms.