13 replies to this topic

[Pyrock]

Over the weekend, I had a problem with my C180 SCIC. At first, it felt like it simply had no power although the RPM's were normal. The dead giveaway was when it reached ~6000 rpm, it would slip and go all the way to 8K rpm's. It felt like the impellor broke loose at 6K rpm's like a slipping clutch. It WOULD reach 25mph but only if you gradually increase the RPM. It felt like the connection between the motor and impellor would loosen when a substantial load was applied.

Any ideas? I have an appointment for warranty work but it's 1 1/2 weeks away. I probably need a "boat break" anyway.

Thanks in advance.

[stevenh]

Over the weekend, I had a problem with my C180 SCIC. At first, it felt like it simply had no power although the RPM's were normal. The dead giveaway was when it reached ~6000 rpm, it would slip and go all the way to 8K rpm's. It felt like the impellor broke loose at 6K rpm's like a slipping clutch. It WOULD reach 25mph but only if you gradually increase the RPM. It felt like the connection between the motor and impellor would loosen when a substantial load was applied.

Any ideas? I have an appointment for warranty work but it's 1 1/2 weeks away. I probably need a "boat break" anyway.

Thanks in advance.

Since the pump is direct drive from the crankshaft, it is very unlikely anything is slipping. It is much more likely you are cavitating. Check your wear ring and impeller for any dings or wear. Make sure there is nothing stuck in your pump (at the inlet or exit). Most times when you have problems, something is stuck in there. It does not take much at all to screw up the water flow.

Steve

[Pyrock]

I spoke to a co-worker who is a mechanic and is a Vietnam Vet. He was a mechanic on those PBR which happen to be jet boats. He said that they had some kind of retaining pin that connected the drive shaft to the impellor shaft. He said that it was designed to break of anything jammed the impellor. The pin would break so nothing else would.

Do ours have the same type of pin? If so, it sounds like the problem. It felt like the rubber gasket/gromet was the only thing keeping the drive shaft connected to the impellor shaft so when there was a load applied to the impellor, it would slip.

[tiggerman]

I spoke to a co-worker who is a mechanic and is a Vietnam Vet. He was a mechanic on those PBR which happen to be jet boats. He said that they had some kind of retaining pin that connected the drive shaft to the impellor shaft. He said that it was designed to break of anything jammed the impellor. The pin would break so nothing else would.

Do ours have the same type of pin? If so, it sounds like the problem. It felt like the rubber gasket/gromet was the only thing keeping the drive shaft connected to the impellor shaft so when there was a load applied to the impellor, it would slip.

You should have a splined shaft driving the impeller.

[Pyrock]

Do our boats have a shear pin anywhere that connects the drive shaft to the impellor shaft?

When I checked out the drivetrain after I got home, I could not see any visible damage. I checked both ends of the jet drive. The only thing I noticed was a rubber piece that looked like it covered the portion where the drive shaft and the impellor shaft connected. It was rippled on one side as if it twisted. That was it. I guess I'll find out next week. At least it's still under warranty and I didn't do anything out of the ordinary that would void the warranty. It went out while I was on the opposite side Lake Tahoe from where I launched so I had to limp home about 5 miles at 8 mph.

[tiggerman]

Do our boats have a shear pin anywhere that connects the drive shaft to the impellor shaft?

When I checked out the drivetrain after I got home, I could not see any visible damage. I checked both ends of the jet drive. The only thing I noticed was a rubber piece that looked like it covered the portion where the drive shaft and the impellor shaft connected. It was rippled on one side as if it twisted. That was it. I guess I'll find out next week. At least it's still under warranty and I didn't do anything out of the ordinary that would void the warranty. It went out while I was on the opposite side Lake Tahoe from where I launched so I had to limp home about 5 miles at 8 mph.

Splined shafts have from time to time spun in the impeller, but are usually a sign of age AND lack of maintenance (grease on the splines). No shear pins that I am aware of.

[Pyrock]

Splined shafts have from time to time spun in the impeller, but are usually a sign of age AND lack of maintenance (grease on the splines). No shear pins that I am aware of.

Can sucking up sand or stones cause this? I didn't see any visible damage to the impellor when looking into the drive from both ends.

[tiggerman]

Splined shafts have from time to time spun in the impeller, but are usually a sign of age AND lack of maintenance (grease on the splines). No shear pins that I am aware of.

Can sucking up sand or stones cause this? I didn't see any visible damage to the impellor when looking into the drive from both ends.

Sucking up sand and stones can and will damage your wear ring and impeller, possibly to the point that your pump begins cavitating, as stevenh has pointed out. There should be very little clearance between the impeller blades and the wear ring- excessive wear will cause your pump to "slip".

[Yuji]

If you were only able to generate 6500ish rpms and little speed/power then it's definitley your supercharger clutch! If it was your wear ring you would suffer cavitation all over the rpm spectrum depending on load. have your supercharger checked...it should take 8lbs of torque to cause the clutch to slip.

[Pyrock]

If you were only able to generate 6500ish rpms and little speed/power then it's definitley your supercharger clutch! If it was your wear ring you would suffer cavitation all over the rpm spectrum depending on load. have your supercharger checked...it should take 8lbs of torque to cause the clutch to slip.

I was able to generate plenty of RPM's. With 3-4 people, it would slip at 6500ish. WIth just me in the boat, it would still slip but reach over 25 mph before it slipped/cavitated. It would slip at various rpm's and go all the way to 8000 rpm's. I'm pretty sure the supercharger drive belt is fine especially since there is very little load on these motors. I've installed many supercharger belts and slipped a belt in my car once and I dont believe that's the problem. I'm pretty familiar with supercharger belts and played with belt/pulley/tensioner combos in my 03 Cobra and this feels and sounds very different. Nevertheless, it's worth checking. Thanks for the input.

[Yuji]

well, first of all there is no belt on the seadoo supercharger, it's gear driven. It uses small ceramic washers that when torqued will slip at 8ft/lbs. I hope you find your problem soon and let us know what the culprit was.

[Pyrock]

well, first of all there is no belt on the seadoo supercharger, it's gear driven. It uses small ceramic washers that when torqued will slip at 8ft/lbs. I hope you find your problem soon and let us know what the culprit was.

No belts? That's a good thing because they are a PITA!! I have an Eaton in my car and belts suck!! Thanks for the info!!

I'll be sure to let everyone know what the problem is.

[Pyrock]

Well, it's repaired. They said the problem was the drive shaft boot that covers the splines. It was twisted which caused cavitation at higher rpm's. I also had the wear ring replaced at my cost. Apparently, the wear ring and boot DOES NOT get along with large volumes of sand traveling at high velocities through the jet. Go figure?

Lesson: "Honey, next time wait until the boat is off the beach before you hammer the throttle. I know you love the hole shot but wait until you have at least 24" of water under you before you go like a bat out of hell."

[tiggerman]

Go figure... glad you got it repaired.