Awful noise freshly rebuilt motor

[NickCawks]

Morning guys. I took my 95 XP to the lake yesterday and had it on the water for about 5 minutes. I was warming the motor up and had not gone over 10% throttle. After about 5 minutes of the motor running, I felt the ski start to bog down so I gave it a little more throttle assuming that because I have the carbs set a bit rich for safety I had started to flood. When I put the throttle down (about 40%) the ski lifted onto plane and started to take off then just shut down. Upon trying to restart it all I could hear was a click of the starter. My two immediate assumptions were that the ski had actually flooded itself self so bad that it locked up OR the non-OEM starter I am running gave out on me.

Being that I had not gotten very far out into the water I hollered at my fiance who was on my GTX to swing back around to me and give me a tow back to the beach so I could take a look. She towed me the two minutes back to the beach. I am a pretty big guy and was unable to get inside the hull and pinch the hose as when I tried I almost rolled the ski. Not sure if this is a big deal because of how short the distance was but wanted to know if you guys think this could be a problem.

Upon arriving back at the beach I immediately pulled the plugs and tried to turn it over as my main thought was that it had flooded. To my dismay, this was not the case. When pushing the start button I am getting a sound I have never heard before. I took a quick video of the sound so I could post it and then decided not to hit the start button until I had gotten a better idea of what was going on. Link to video

Now this motor is brand new. I just got it back from SES which I paid for a full engine rebuild. This is the second time I have had the ski out with the new motor. The first time out my test and tune went great and the ski ran perfectly which gave me no cause for concern when I took it back out yesterday. This brand new motor has .3 hours on it.

I am running pre-mix as well as the oil pump is functioning. The carbs were freshly rebuilt (genuine Mikuni) last summer and have about an hour on them, they were set to the factory tune and then through my test and tune on the first day out, I ended up richening them out just a tad because the ski was running great but I wanted to be on the safer side during break-in.

I am very unsure what this sound could mean. To me it sounds like something internal has broken. I am a little alarmed as the motor hasn't even gone through 2 bars on the gas gauge yet and I'm ready to flip out at SES if this is an internal issue. I am racking my brain thinking "what could I have done wrong" and I keep coming up short. I don't think I did anything wrong I was in the very beginning stages of going through the same process I have used to break multiple motors in and never had an issue.

let me know what you guys think, any and all input is welcome. I'm crossing my fingers that this is something that can easily be remedied as I am entering yet another summer with the possibility of one of my 2 skis being down again.

 

[GGuillot]

Hope it's not the case, but it sounds like something related to the rotary valve gear being stripped. It started running bad as it stripped and fell out of timing. That grinding noise sounds like the gear.

I'd remove the pump and the rotary valve cover, spark plugs out, turn it at the PTO flywheel and see what's going on.

 

[mikidymac]

Could just be the junk starter. I would pull the rear plastic PTO cover and see if you can turn it over by hand before you start taking anything apart.

 

[GGuillot]

Could just be the junk starter. I would pull the rear plastic PTO cover and see if you can turn it over by hand before you start taking anything apart.

Did you watch/listen to the video? Heck of a grinding noise, he's got the PTO cover off and the starter is turning the motor.

 

[IDoSeaDoo]

Yea, turn it over by hand. Could have lean seized and busted a ring. Did the plugs have any trash on them, like grey or silvery stuff? Even though you rebuilt the carbs, you could still have an air leak somewhere in the fuel system causing it to be lean. I've had that happen once. You did change the fuel lines from the grey ones, right?

 

[NickCawks]

Hope it's not the case, but it sounds like something related to the rotary valve gear being stripped. It started running bad as it stripped and fell out of timing. That grinding noise sounds like the gear.

I'd remove the pump and the rotary valve cover, spark plugs out, turn it at the PTO flywheel and see what's going on.

I went out and tried to spin the PTO by hand. It is "freely" spinning and by that I mean the pistons do not seem to have any sort of obstruction. However, the clicking noise happens while I'm spinning it.

Yea, turn it over by hand. Could have lean seized and busted a ring. Did the plugs have any trash on them, like grey or silvery stuff? Even though you rebuilt the carbs, you could still have an air leak somewhere in the fuel system causing it to be lean. I've had that happen once. You did change the fuel lines from the grey ones, right?

The spark plugs were brand new and sprayed with an air compressor before installing. I will take a look and see if I can find any gas leaks.

I am definitely leaning towards some sort of rotary valve issue being the cause.

The big issue I'm faced with now is that per the warranty on the motor if I were to disassemble it then I have voided the warranty.

I will have to give tom at SES a call and see how he would like to proceed. I pray to God he doesn't tell me I need to send it to him and wait another 7 months for it to come back.

 

[racerxxx]

Just pull the rotary oil line off on the carb side, it's coming out anyway. Get a syringe, put a hose on it. Draw fluid into the syringe. If you see brass shavings, stop, pull engine and send back.

 

[IDoSeaDoo]

racerxxx has a great point, check the RV chamber for brass. The way I drain those things is disconnect it at the oil tank (rag below) and immediately plug the tank, and raise the inlet hose higher to stop it from bleeding. Then, you can lower that hose to the point where it free flows. It's tricky due to its length, and you can't crimp it as that'll stop the flow. It's easier with certain models than others. XP may be a bit tight.

 

[etemplet]

I'd make sure the stator isn't rubbing on the rotor. I"ve taken a few engines apart that have had obvious rubs. Rotary valve area and oil pump gear and such would be good checks. That noise sounds like a constant rub to me but I don't hear that well. Ha ha. Good Luck !!

 

[AKnarrowback]

I'd make sure the stator isn't rubbing on the rotor. I"ve taken a few engines apart that have had obvious rubs.

My thought as well.

Pull the rv plate off and see how the disk timing is, see how much rotation you can get out of the rv shaft. If it all looks good then pull the mag flywheel and inspect things. Before you pull it do a spark check.

I have had brass gears fail, but they never made that sound.

 

[NickCawks]

Thanks guys for all your input. I will jump on these suggestions and post my findings.

 

[NickCawks]

Haven't had time to get into the ski again. Too many covid projects going on lol..

I did talk to Tom from SES. He says the sound is unmistakably the rotary valve.

 

[NickCawks]

alright, folks. I just got the motor pulled out of the ski finally.

100% no questions asked, its the rotary valve gear.

while lifted up on my cherry picker I decided to turn the PTO while looking into the carb. The PTO spins then I hear a click followed by the piston blowing off compression. The entire time this is happening the rotary valve does not move.

I am assuming that the click noise I'm hearing is the valve slipping passed the stripped out brass gear.

I am waiting for some oil to drain out of the block and off the motor mount and will pull the oil pump off and take some pics if it's really bad.

At least we now know that when you hear a ratchet-like sound its probably the rotary gear. Which I will give props to Tom over at SES for identifying the problem immediately without anything but the video.

 

[GGuillot]

I called it because of the poor workmanship shortcut reputation SES has. Why didn't he (Tom at SES) change the rotary shaft bearings? I bet he didn't. Worn bearings could cause the misalignment and trash the brass gear. Did he check the rotary valve shaft for trueness? unbent? I don't understand why people don't change them doing a rebuild, cost me $7 for both bearings on my 787 builds and a little more effort to change them. The difference between a failure on the water or not after a rebuild.

 

[mikidymac]

The other thing that causes issues is the iron gear on the crank can move if a rotary valve locks up from something like a bolt falling into the intake.

Then it will continue to eat the brass gear no matter what you do.