Sporster 155 poor hole shot

[Trever]

Just picked up a 2005 sportster 155hp. Boat runs great and has great top end but it is lacking on the bottom end. At idle when I pin the throttle I would expect the boat to launch hard. Instead it will engine revs quickly and I can hear it bouncing off the rev limiter until I get on plane. Im new to jet drives. Any suggestions for what I should check first?
Trever

 

[devonte007]

What you are experiencing is cavitation in the propulsion system. Very likely that your wear ring and/or impeller need replacement. The jet pumps have very tight clearances, and its a maintenance item. It is also likely that your carbon ring (drive shaft seal) also needs replacement.

Time to pull the jet pump and inspect it. Feel free to post pictures here and we'll let you know how it looks, and give you a better diagnosis. If you have some mechanical experience it is not difficult to do yourself. You may also want to download the shop manual for your boat from this forum, just click the "manuals" link at the top of the page. Good luck and let us know how it goes!

 

[El Toro 33809]

Inspect the impellar/wear ring visually with a flashlight. The clearance should be about the thickness of a dime or less. If it seems more than that, the wear ring should be replaced

 

[Trever]

Thanks for your guys help! Heres where im at so far. Removed the pump and it appears to me the wear ring is shot. There are spots where the clearances exceed 1.5-2mm to the impeller. Did some reading here on the forum and found a post about sticking the pump in the freezer to get the ring out,,,tried it and it worked great! Where is the driveshaft seal and how can I tell if its worn? Now that im into it what else should I check? I want to put this thing back together with peace of mind that it will be good for this boating season! Heres a few shots.....

Ring is warped. What causes this?

 

[Trever]

Ok,,so I put everything back together with a new wear ring. Took it for one ride and the initial take off was great. I played around for about 20mins or so and noticed the cavitation was coming back. Took the boat out of the water and looked up through the intake grate and noticed the new wear ring was already grooving. What could be my problem? The impeller does not have any play when I had the pump out. When I slid in the new wear ring I could spin the impeller with out it touching the wear ring. I took the new wear ring out again tonight and I could see that the ring had spun in the pump housing and it didnt take any effort for the ring to come out of the housing. Really need some imput. Thanks.

 

[Trever]

Anyone have any suggestions?

 

[Davo070]

I would say something in the impeller housing is not aligned/seated correctly, so missing washers or something, or you have a warped shaft which is causing the blades to dig into the wear ring. Just my 2 cents, and I for sure aint no expert...

 

[devonte007]

Is your new wear ring a Seadoo OEM? Have heard of problems with non OEM wear rings.

If you are using OEM, then the pump housing may be warped and may need to be replaced. When you replaced the wear ring did you take off the nose cone and look inside at the bearings and grease? Like Davo indicated, sounds like a problem with the housing, impeller, or bearing assembly. Might be time for a full rebuild of the jet pump. I bought my boat used as well, and had to replace the whole jet pump and impeller b/c water got in the bearings and messed everything up.

If you have caliper gauges you could check the housing to see if it is warped. The old wear ring certainly looked out of round. Might be worth it to take the pump into the dealer and have them check it out to see if it is salvageable. I think it is probably something to do with the jet pump housing and not the drive shaft itself. A warped drive shaft would cause vibrations and would probably chew up your drive shaft seal. Investigate the pump itself first, and if it checks out to be good we can dive deeper into the problem.

 

[Trever]

Im not sure if the wear ring was OEM. I did buy it from a seadoo dealer so im just assuming its OEM. I suspect my pump housing is bad because when I put in the new wear ring I was able to push the new one in by hand. It actually looks like the wear ring has spun in the housing. Someone put in screws through the pump housing into the wear ring to keep it from moving in the housing. At least I dont think these screws are factory. For now ive ordered a new pump housing,,with bearings and the works. Im weary about putting in all these new parts if theres something else causing my issue.

Another thing, I seen in the service manual the torque spec on the four main nuts on the pump housing is only 16ft/lbs. When I originally took off the pump, them nuts were definately over torqued. Could this have warped the housing?

This jet drives stuff is all new to me so I appreciate the input guys!

 

[Davo070]

I think you should fix the problem with your new housing and bearings, screws into the wear ring are definitely not OEM.

 

[thor7000]

actually there are small screws which hold the wear ring in place that are OEM. I have a speedster200 and one of my pump housings is slightly out of round which is causing some cavitation but since I have 2 engines the boat still performs great. Another option instead of getting a new pump housing is installing a stainless steel wear ring, they will maintain a perfect circle but only downfall is if you suck something up the impeller takes the hit.

 

[Davo070]

I stand corrected, thanks for clearing that up Thor, I have the 200 too and did not know this, I am grateful that I have not had to pull the pump since I got it, probably my dumb luck I guess but i was planning on taking a look at the wear rings when I got it back from the delaers.

 

[devonte007]

I know that there were some pumps out there that used screws to hold the wear ring, but always thought they were some of the older 2-stroke ones. I was always under the impression that the 4-tec pumps do not use screws... I haven't worked on enough of these to be any expert though.

I do agree that the new pump housing and bearings should solve your problem. Just be careful assembling everything so that it is true and strait. Have never assembled the bearings into a new housing before but I know it is easy to get things out of alignment if you are not careful. Also, make sure the impeller is in good shape and clean up any knicks with a file or dremmel if they are not bad.

If you are still worried about the drive shaft it should not be that hard to remove and check at this point. Just loosen the bellows clamp, and the circ-clip from under the SS ring and it should slide right out. Then you can check to make sure it is not warped for piece of mind and clean it up if it needs it.

As for what causes the pumps to warp, I am not exactly sure. I would thing that over torquing the bolts is a logical reason as it might not allow everything to expand properly as it heats up. Also, if it was cavitating real bad and someone revved the crap out of it, the pump could heat up. I have seen pictures of wear rings that have been melted like this.

Anyway, I think you are good to go once the new parts arrive. Also, I commend you taking on such a project yourself being kind of new to these boats. Good luck and let us know how it all turns out!

 

[thor7000]

If it was me....I would buy a new Solas impeller and install it with all of your new parts seeing how you have everything apart!!

 

[Trever]

Something else Ive noticed looking over the boat. The plastic line between the two pump water passages is kinked. Im not sure what these passages are for but heres a picture.

 

[thor7000]

Dont worry, that's normal!!

 

[Trever]

What is the purpose of the water passages?

 

[thor7000]

What is the purpose of the water passages?

to be honest, I don't know why they are there...just know I have the exact same on each of my pumps in the engine compartment.

 

[Trever]

So im thinking im gonna take thors advice and get a new impeller to go with all my new parts. What should I go with for an impeller? Stock? Aftermarket?

 

[thor7000]

So im thinking im gonna take thors advice and get a new impeller to go with all my new parts. What should I go with for an impeller? Stock? Aftermarket?

Go with the aftermarket Solas impeller....will be cheaper then an OEM one and provide better hole shot and slightly better top end. Buy it in the U.S from one of the aftermarket parts shops, would be allot cheaper then buying it in Canada!! Just make sure they send it via USPS instead of UPS....allot cheaper in shipping and duty fees!!

 

[Trever]

So I got all my parts today. I was very surprized to see that the new housing is steel instead of plastic like the original one. After inspecting my old housing more closely I found the housing was definately warped. The housing was actually ovaled. Shes all back together and its working great! Played around in the lake for about 30mins. My top speed with one passenger is 48mph GPS. Im assuming this is normal for this boat. Thanks everyone for the help.

BTW...I asked a question earlier on about them two water passages at the top of the impeller housing. I did some research and found out why they are there. This same housing is used in some PWC seadoos. The ports are bilge syphons. Boats have bilge pumps so the ports are not used in boats. This is why they are capped off with a tube.

 

[thor7000]

Glad to hear everything is working great now!! How much did the new steel pump housings cost?? I may consider replacing mine on my speedster200 since they are slightly out of round

 

[Trever]

I payed $279 Canadian. Much better then the chinsy plastic ones!

 

[devonte007]

Great to hear everything is back together and running smooth. 48 mph is about normal top speed for my boat as well. Thanks for the info on the water passages, I never noticed them on my boat and feel better now knowing why they are essentially capped off.

Have a great boating summer!