No propulsion except at idle

[mugfordd]

I was running almost flat out one day and everything was fine. All of a sudden I lost propulsion. I was able to creep along at idle, but as soon as I gave it some gas, the motor would rev up but I'd go nowhere. I've read several posts that had similar problems and the suggestions that came back seem to indicate three possible problems. One, there was something (like a stick) caught in there. Two, the wear ring needs replacing. Three, the carbon seal needs replacing. The only thing that I wonder about is why I had such a sudden loss of propulsion. Can anyone offer their opinion on whether one of my three possible causes is correct or if it's something else? Any input is greatly appreciated. Thanks.

 

[Cheflen]

I was running almost flat out one day and everything was fine. All of a sudden I lost propulsion. I was able to creep along at idle, but as soon as I gave it some gas, the motor would rev up but I'd go nowhere. I've read several posts that had similar problems and the suggestions that came back seem to indicate three possible problems. One, there was something (like a stick) caught in there. Two, the wear ring needs replacing. Three, the carbon seal needs replacing. The only thing that I wonder about is why I had such a sudden loss of propulsion. Can anyone offer their opinion on whether one of my three possible causes is correct or if it's something else? Any input is greatly appreciated. Thanks.

First guess would be the wear ring, if you sucked up a rock or something and it damaged the wear ring you would get a sudden loss of propulsion. Definitely would be the first thing I would try as it should be the cheapest and always a good maintenance item to replace

 

[mugfordd]

Thanks Cheflen for the reply. You might be right that I sucked up something. It definitely wasn't a rock though because this happened in deep water. But I suppose it could have been something floating that was still hard enough to cause the damage. I am going to try and take off the pump this weekend and look for a damaged wear ring.

I just thought of something that might indicate that it's the carbon seal. I have only left my Sea-Doo in the water overnight one time. In the morning, it was almost completely underwater. Would that mean that water could have leaked in all night through a bad carbon seal?

 

[Cheflen]

Thanks Cheflen for the reply. You might be right that I sucked up something. It definitely wasn't a rock though because this happened in deep water. But I suppose it could have been something floating that was still hard enough to cause the damage. I am going to try and take off the pump this weekend and look for a damaged wear ring.

I just thought of something that might indicate that it's the carbon seal. I have only left my Sea-Doo in the water overnight one time. In the morning, it was almost completely underwater. Would that mean that water could have leaked in all night through a bad carbon seal?

Yes carbon seals would leaks water into the hull of your seadoo, I would just check for any other leaks before diagnosing that. But that could be the culprit of your cavitation and leaking of water into the hull.

 

[Digdog]

I think you lost the splines inside the impeller or the crank adapter, wear ring or carbon seal would cause some loss of propulsion but not a total loss as you describe. Has to be a major mechanical malfunction to lose everything.

 

[mugfordd]

Digdog, thanks for the input. I didn't entirely lose everything. I could still coast along at idle. So I didn't lose everything. I guess I will find out when I get a chance to remove the jet pump.

 

[mikidymac]

Get on your back with a flashlight and look up into the pump. It is more than likely the wear ring or impeller.
It also sounds like your carbon seal is on the way out but it would not cause a sudden loss of forward momentum. IF it did your ski would be on the bottom of the lake as it would be gone and a direct hole from the lake into the bilge.

 

[Digdog]

Digdog, thanks for the input. I didn't entirely lose everything. I could still coast along at idle. So I didn't lose everything. I guess I will find out when I get a chance to remove the jet pump.

The propulsion in your machine is direct drive to the impeller, so unless something is completely blocking the intake or your impeller has plugged with weeds or failed you should always have a fair amount of propulsion no matter how bad wear rings or carbon seals get. Yes look into the impeller before you take it apart to see if you sucked something in, strange things happen.

 

[mikidymac]

Digdog, thanks for the input. I didn't entirely lose everything. I could still coast along at idle. So I didn't lose everything. I guess I will find out when I get a chance to remove the jet pump.

The propulsion in your machine is direct drive to the impeller, so unless something is completely blocking the intake or your impeller has plugged with weeds or failed you should always have a fair amount of propulsion no matter how bad wear rings or carbon seals get. Yes look into the impeller before you take it apart to see if you sucked something in, strange things happen.

That’s not entirely true. If you have an OEM wear ring and the rubber separates like some do when they get old you will have little to no acceleration. It’s just like a car with a slipping clutch. Engine will rev to the limiter and ski will barely move.

 

[Digdog]

That would make sense

 

[Chester]

Did you inspect your impeller from underneath through the intake grate? You most likely (99% chance) got a stick stuck on the impeller. If it all looks good, try it again in the water. Sometimes the stick will wash out as you load onto the trailer.

Chester

 

[Chester]

A small 1/2" stick stuck on the impeller will cause exactly what you described.

Chester

 

[mugfordd]

Wow, thanks for all the input. I took the jet pump off today and:

1) There was no stick stuck inside
2) The wear ring is brass in mine and is only slightly scored
3) The impeller blades look really good. There is only one small ding on it.
4) It's possible that the splines in the impeller are gone. But if they were, I doubt that explains why I suddenly lost propulsion. If that were the cause, you'd think it would happen gradually, wouldn't you?

That only leaves one possible cause that was mentioned on here and that's the carbon seal. I just found a dealer that I think I can trust and I think I may have no choice but to take it in. Hopefully it's nothing expensive.

If anyone has any other ideas, I would love to hear them. Thanks again for all the support.

 

[mugfordd]

Did you inspect your impeller from underneath through the intake grate? You most likely (99% chance) got a stick stuck on the impeller. If it all looks good, try it again in the water. Sometimes the stick will wash out as you load onto the trailer.

Chester

Chester, I suppose you are right. Maybe I had a stick caught on there and it has already fell off. I never tried putting it back in the water again so I guess it's possible that I don't even have a problem anymore.

 

[mikidymac]

Can you post a picture of the pump? I haven’t seen a seadoo pump that hasn’t had a wear ring let alone a brass one.

 

[Digdog]

Wow, thanks for all the input. I took the jet pump off today and:

1) There was no stick stuck inside
2) The wear ring is brass in mine and is only slightly scored
3) The impeller blades look really good. There is only one small ding on it.
4) It's possible that the splines in the impeller are gone. But if they were, I doubt that explains why I suddenly lost propulsion. If that were the cause, you'd think it would happen gradually, wouldn't you?

That only leaves one possible cause that was mentioned on here and that's the carbon seal. I just found a dealer that I think I can trust and I think I may have no choice but to take it in. Hopefully it's nothing expensive.

If anyone has any other ideas, I would love to hear them. Thanks again for all the support.

Look at the clearance between the impeller and the wear ring, you can measure it with a feeler gauge. When mine are new there is only about .020'' clearance. Pull the shaft out of the engine to check the splines in there if you already have the pump off just to be sure, while you are in there the carbon seal/boot is an easy check.

 

[mugfordd]

Thanks Digdog, that's a good suggestion. I will try that when I get the chance. The Sea-Doo isn't stored at my home. Here are some pictures.

 

[mugfordd]

Can you post a picture of the pump? I haven’t seen a seadoo pump that hasn’t had a wear ring let alone a brass one.

See my posted pictures. I have one that shows the wear ring in the pump and one with the wear ring outside the pump. I was real lucky because my wear ring just fell out when I turned the pump over. I had no trouble getting it out.

 

[Digdog]

See my posted pictures. I have one that shows the wear ring in the pump and one with the wear ring outside the pump. I was real lucky because my wear ring just fell out when I turned the pump over. I had no trouble getting it out.

I wonder if the wear ring was spinning along with the impeller? it is supposed be friction fit when installed. Clearance looks okay, but I would look at a new wear ring and if it's loose when you install it you will have to get a new housing also. Looks like there was lots of brass dust/shavings in there ? Am I correct to see this? You also need to clean and grease the splines before it goes back together, use high performance synthetic marine grease.

 

[mugfordd]

Even if the wear ring was spinning, would that make any difference? It would still be doing it's job wouldn't it? I agree, the clearance looks OK. There wasn't any brass dust/shavings. It looks like the dealer will be doing the work, so they will be putting it back together. I will make sure they know about the grease.

My thinking is that the splines in the impeller look worn down. See the picture I took of them. Do you agree?

 

[mikidymac]

Those splines sure look shot to me. I have never seen a brass wear ring like that before. I would go with an OEM rubber one as wit the brass ine if something gets in there you will destroy the impeller.

 

[mugfordd]

Mikidymac, thanks for the feedback. I agree about the splines. I have never seen what the splines look like in a new impeller, but I can tell you is that they aren't as deep as the splines on the shaft. The shaft splines still look great.

You make a good point about the brass wear ring. The replacements aren't that expensive, so I will replace it at the same time as the impeller. The new ones are rubber? I thought they were made of nylon.

Wish me luck that this is the fix!

 

[mikidymac]

The OEM ones are fibergalss coated in rubber. The theory is if a rock goes through it, it will damage the rubber an not the impeller.

 

[etemplet]

Wear Rings. Had my first experience with the SPI. I knew it wasn't in great shape and since I got caught up on the other skis I figured I'd change it out. Especially after my wife blew by me last weekend. I'd say it's pretty bad. I wonder if I'll get a few more MPH top end?? The impeller leading edge needs some attention but I got that covered.

 

[Chester]

Those impeller splines look perfect to me.

Chester