02 4-Tec - At speed and then No Thrust

[Harry Reynolds]

Hi everyone! This is my first time posting - and under bad circumstances. This weekend we were cruising along and all of the sudden nothing. Engine runs fine, but almost zero thrust. It was just enough to get us back to the ramp. Not know what it is supposed to look like, I'm not sure if anything is wrong. All of the blades on the impeller look good and straight. Any ideas?

 

[Andrew_lbreman]

Hows the wear ring. Was the ski vibrating more than normal. You have to give more info on the situation. was it the first time out this year. did the light come on and beep at you. Could be limp mode. do you have oil. is there crap in the fuel. do a compression test. did you store it with no fuel? lots of variables and causes but not enough information given to give you the answer. You can check the wear ring by removing the reverse, steering, and opas bolts. Also you have to remove that little hose from the top of the jet pump. I am talking about the exterior of the ski on the jet pump. Then you remove the 4 nuts that are closest to the transom. This will allow you to pull the pump off and check out the impeller to make sure your bearings are good and spin free, also the wear ring and nothing stuck in the impeller. MAKE SURE that when you remove the pump you are careful. DO NOT snag anything because you can easily break the plastic nuts on the steering and reverse cables. Then you go out and have no steering.

The Compression you can get a cheap gauge from auto parts store. Make sure to disconnect all of the plugs (coil packs) and remove the plugs, then test one cyl at a time. if you cant start it first then put a few drops of gas of light oil in the plug hole to help get a true reading.

Last only check one thing at a time and then put it back together before you move to checking the next thing. If you need parts consider the site links but also check out http://www.pwcperformanceparts.com/servlet/Service. They have good prices and also can help guide you over the phone as to the problems. Dont call and waste his time if you arent going to give him any business though. It is not my shop but he has been helpful to me many times in the past so I figured I'd support his products.

 

[Harry Reynolds]

Andrew,
Thanks for the post - Here is what I can tell you:

-Wear Ring - Not being intimate with the ski - I'm not sure what it should look like. When I look around the front and back of the impeller - it all looks ok. If there is something missing - I couldn't tell you.
-First time out for the year. Put the ski in and rode 20 miles to the other end of the lake to see some friends. Rode around and tubed a little bit. Headed home and it lost power about 5 long, slow miles from the ramp.
-It idles fine - and will rev fine to about 3500 rpm. Anything more than that and it starts to vibrate like mad.
-I dont think it is engine related as the engine is doing everything you ask it to do.
-No warning lights
-Nothing stuck in the impeller
-Impeller looks fine - no bent or missing blades

Tonight I will start taking the back end apart to get closer to the action of the actual jet.

Should I be able to turn the impeller over by hand? I would guess no as it is direct drive with no "clutch" between it and the engine.

Thanks in advance for all the help on this!

Harry

 

[Andrew_lbreman]

Vibrating sounds like the wear ring. How is it out of the water? Does it rev up? I would pull the jet pump and look at the intake. The impeller should have no play but spin free and there is a plastic wear ring around the impeller. It should be smooth and not all chewed up. That's what your problem sounds like. Don't run it while the pump is off unless you remove the drive shaft. It can slap and bang into watertight parts causing them to break.

 

[Coastiejoe]

Wear ring is likely the issue.

The gap between the impeller and the wear ring should be the thickness of a dime, no greater.

 

[Harry Reynolds]

Thanks again- Tonight we disassemble!

 

[Harry Reynolds]

Ok, now I'm stumped. I took the whole back end off tonight. Everything looks great. Wear ring looks good, Impeller looks good, Splines on both shaft and impeller look good. I put it all back together and came in to read up some more on the forum. I found a few threads that talk about stripping the splines on the engine side of the prop shaft. Is this a common thing? It would seem like an extreme case to be able to do this. The ski has 180 hours on it - mostly from my sister in law who bought it new and rode it like a nun going to church.

Tag guys - you're it! Any more ideas??

 

[Andrew_lbreman]

Do you have pictures of the front of the pump and wear ring. There should be very very little space between the wear ring and impeller. Sometimes they look okay but have too much of a gap and still need to be replaced. I dont have it here but look up the gap and see if you think you are close. It doesnt take much for you to loose power with these things.

Next...
if the pump is good bolt it back up and get it on correctly. Make sure to not force the splines but to fit them together and get a good seal around the front of the pump to the transom. get a compression gauge and pull the spark plugs. Look for any sign of damage on them. look into the plug hole for anything that doesnt look right. Check your oil and make sure you have plenty. Then put the compression gauge on each cyl and get the readings. they should all be the same for the most part. Cold you may want to spray a little wd40 or something into the cyl to get a good reading. Not a lot just a little squirt to wet the rings and seal it up better.



if that is good get the hose out like you are flushing it and run it for a minute in the driveway. rev it up a little and see if you go past the 3500 rpm area. I have to go but will check back tonight and see if you found anything wrong. My bet is still on the wear ring so if possible post some pics or use a feeler gauge and measure the gap.

 

[Harry Reynolds]

Measuring it with a feeler gauge, there is betwen 0.013" and 0.018" gap from the outside of the impeller to the wear ring. Where the impeller runs on the wear ring is rough, but not ugly. It looks about how I would have expected it to look. I don't think that it is engine/power related as the engine would rev just fine - just no thrust. Tonight I will run it in the driveway to see.

 

[Dr Honda]

When it's an "All the sudden" loss of thrust... and vibration........


IF, you don't see a hunk of rubber missing from the wear ring... OR... if you didn't strip out the splines in the PTO... I can almost guaranty that you sucked up a trash bag that was floating in the water. Once you shut off the engine, and put it on the trailer... it fell out.


I bet if you put it back into the water... it would be fine.

 

[Duane72]

Harry, you said the engine would rev fine just no thrust, but you said it would vibrate like crazy above 3500rpm. When you had the pump off did you try to "wiggle" the impeller from side to side at all to check free play? I worked on an older GTX that had never been serviced (regrease the impeller bearing) and the seal failed. It would run but just before fail began to vibrate like a bad wear ring but it was the impeller "wobble" that was vibrating.

Also, if the splines on the motor side of the driveshaft are bad you should be able to feel a lot of "slop" when you try to turn the driveshaft by hand. It will spin in either direction a little before "catching" and trying to turn the motor.

 

[Coastiejoe]

Ok, now I'm stumped. I took the whole back end off tonight. Everything looks great. Wear ring looks good, Impeller looks good, Splines on both shaft and impeller look good. I put it all back together and came in to read up some more on the forum. I found a few threads that talk about stripping the splines on the engine side of the prop shaft. Is this a common thing? It would seem like an extreme case to be able to do this. The ski has 180 hours on it - mostly from my sister in law who bought it new and rode it like a nun going to church.

Tag guys - you're it! Any more ideas??

It is a fairly common issue having the splines on the drive shaft go bad. However, it is under a heavy load where it is most prevalent as that is the time of most torque.

So if it is going to "slip" it will for sure do so under initial acceleration long before in the mid-range or just cruising along.

 

[Coastiejoe]

After re-reading all the posts, I would agree that it is likely that you had something in the impeller area and it simply fell out.

I had a twig that was no bigger than 1/4 in diameter and about 2 inches long. You would have thought I have a Volvo in there. It created a poor performance and a slight vibration issue..

 

[Harry Reynolds]

After re-reading all the posts, I would agree that it is likely that you had something in the impeller area and it simply fell out.

I had a twig that was no bigger than 1/4 in diameter and about 2 inches long. You would have thought I have a Volvo in there. It created a poor performance and a slight vibration issue..

Coastiejoe...You are the winner!! Took the ski out this weekend and it runs like a raped ape. This goes down as the weirdest mechanical issue I have ever (not) had.

Thanks for all of the help guys - I really appeciate it! Have a great trouble free summer!

 

[Coastiejoe]

Coastiejoe...You are the winner!! Took the ski out this weekend and it runs like a raped ape. This goes down as the weirdest mechanical issue I have ever (not) had.

Thanks for all of the help guys - I really appeciate it! Have a great trouble free summer!

Man,,, that's twice this week I was right,,,

Got to love the simple things. Have fun on the water,,,

 

[Ethom]

Hi, I'm new here and currently going through the exact same thing. Past 3500 rpm there is virtually no forward thrust. So the engine revs fine and the rig starts to move then nothing. I almost feels like I am revving it in the driveway upto 7,000 rpm. The impeller and wear ring seem fine. The back end is currently all taken apart everything looks close to new although while I have it out I will replace the wear ring...The splines on the back end of the shaft are all good. Not sure how to take the drive shaft out from the front. My question to all of you should the drive shaft move side to side (on the back end with the front end still in place) I can move it pretty far, maybe an inch in all directions) The splines feel ok on the engine side and there is the slightest rotation and I mean slight, exactly as I would expect. is the side to side play normal? I am really trying to find something wrong else Im going to put it back together and hope I end up with the same issue (non Issue) the original poster to this thread had. I live far from a lake so it not as simple as id like to drop it in and see if it works again. Thanks for the help, sorry for the long winded question, just trying to give you guys something to work with.