Vibration @ 2300rpm???

bassman215

bassman215

Location
Lubbock, TX
Just built a 61x/61x home ported setup in a '91 sn... Got it all installed and it is awesome. Still have fine tuning to do, but I have this weird vibration @ about 2300rpm's.

I thought maybe the 701 engine vibrates more than the 650, but this is not normal. I can really feel it strong in my feet through the tray. The weird thing is my ski has set for about 2 years and before that with the 650 in it I never had a vibration problem. After doing a bunch of searches I was thinking I've got a pump issue since I feel it in my feet the worse, but like I said everything was functioning fine two years ago when I last rode? I checked my coupler alignment per the cylmer manuals specs on distance between the two couplers and also the alignment up/down left/right. Everything checked out there. Any ideas what might be going on? Everything looks good in the pump from just a visual inspection. Haven't tore anything apart. Thanks for the help.
 
Jetaddict

Jetaddict

9 years to retirement...
Location
Tampa Bay
Any odd noises or excessive noises coming from the pump? I know that I had a vibration and noise from my SXR, and it recently took a crap, it ended up being the bearings were shot.
 
Officer Mike

Officer Mike

TJ / SJ / JJ
Location
Harveys Lake
i once sucked up a fishing lure, and another time a milk jug lid. both times it reacted the same as you described. i kno that you said it passed visual inspection. I rolled it on the side in the water and i found the problem. good luck
 
J

John_Ciocca

Location
Carlsbad, CA
I had the same problem with my Superjet. One day I had this vibration in the tray.......after a few rides it just went away so I never found the root cause. It has been more than a year since that happened with no problem.

If there is not any interference and everything is assembled correctly, run it and see if it gets worse or possibly like mine...better.

JC
 
bassman215

bassman215

Location
Lubbock, TX
sflsurfrider said:
did you try checking the alignment with the rubber coupler not in place?
Click to expand...

I did not check the alignment without the rubber coupler. The manual didn't mention checking without it, or maybe I just overlooked it. That will be a pain to pull the pipe back out to get to the motor mounts and loosen them up... Is it better to check it with the rubber removed? If that's what it takes I'll check it out.

Thanks for the help everyone. I haven't had a chance to ride but just about 30mins. I am leaving to go out of town for a week tomorrow so I will have to wait a little longer to check it back out.
 
bassman215

bassman215

Location
Lubbock, TX
Officer Mike said:
i once sucked up a fishing lure, and another time a milk jug lid. both times it reacted the same as you described. i kno that you said it passed visual inspection. I rolled it on the side in the water and i found the problem. good luck
Click to expand...

I'll give it a really good look again. I did notice for just a min or so that it felt like it was cavitating and then it quit, but we had about 4 inches of rain that day and the lake level is up and a bunch of vegetation crap floating around. Thought I probably just sucked up a cattail or something and blew it out. The vibration was there before it ever acted like it cavitated and still there after it felt fine again.
 
bassman215

bassman215

Location
Lubbock, TX
blaster4life said:
i think your supossed to aline without the cupler....mark your placement and the put the cupler in
Click to expand...

I'll have to give that a try.

I am wondering if my bearings are starting to go? I started the ski on the dock tonight for a min. Vibration is there whether in water or not, just seems worse in the water. I did notice some noises I've never noticed. When the ski is idling out of the water it has some noise in the pump. Not constant, more on and off. I really can't describe the sound except, and this may sound dumb, but almost like a pigeon cooing. It's not a squeak or grinding... That may not be a very good way to describe it. :twak: I don't know if that's a normal impeller/pump sound out of water or due to bearing problems?
 
Mouthfulloflake

Mouthfulloflake

ISJWTA member #2
Location
NW Arkansas
so you didnt alighn the couplers when you put this new engine in?

Id bet thats your issue right there.

I use a flashlight, and a long straight edge ( a 3 " razor/scraper blade) and just adjust shims under the engine pan until its even all around.
 
bassman215

bassman215

Location
Lubbock, TX
Mouthfulloflake said:
so you didnt alighn the couplers when you put this new engine in?

Id bet thats your issue right there.
Click to expand...

When I had taken my old engine out I marked all the shim locations and installed exactly the same. I am using the same bed plates, but didn't know how much a new engine case would affect alignment. After I noticed the vibration I checked the coupler alignment with the rubber installed and it checked out good per the manual. Sounds like I need to do it without the rubber... I will redo it when I get back in town week after next. Hopefully that will clear everything up!

I will say this. From the little bit of riding I got done, it sure seems to have a lot more power than my old 650!

I am getting about 167psi in each cylinder with the head I bought from you Mouth. That is with my crappy autozone gauge @ about 3300ft above sea level. Does that sound about right? I am going to try to get my ski by my mechanic buddies and have him slap on his snap on gauge and see what kind of difference there is.
 
Mouthfulloflake

Mouthfulloflake

ISJWTA member #2
Location
NW Arkansas
hmm, I was thinking that head increased my compression about 30 psi over stock.

you could always put a stock head on and check compression to see the difference.
 
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bassman215

bassman215

Location
Lubbock, TX
Mouthfulloflake said:
hmm, I was thinking that head increased my compression about 30 psi over stock.

you could always put a stock head on and check compression to see the difference.
Click to expand...

I'll have my buddy check it with a good gauge after I break it in a little and see what we come up with. I bet it is more than my gauge is reading.

Also, I did port those cylinders. So that may lower it a little if the motor you had it on didn't have a port job?
 
Mouthfulloflake

Mouthfulloflake

ISJWTA member #2
Location
NW Arkansas
you might need to measure the ring gap, measure the bore, and measure the cylinder, to see if you have a tight enough relation ship there to make a good ring seal.

I will tell you though, ive ran motors with compression way lower than that, and they ran well.
 
bassman215

bassman215

Location
Lubbock, TX
A couple weeks ago I spent some time and pulled everything back apart and checked the engine alignment. It wasn't great. I moved a shim or two around and everything was better. Bolted it all back up and STILL have my vibration. Re-aligning the engine might have made a slight difference, but really I don't think it did.

I am using my old 650 crank. Would it make sense that the vibration I am feeling could possibly have something to do with that crank not being balanced to the bigger 701 pistons? That may not have anything to do with it though.

I also checked the play in the midshaft/bulkhead, whatever you call it, and there was some movement, but extremely minimal. You could feel a slight movement up/down but couldn't really actually see the coupler moving up and down.

I am just throwing some stuff out there as possiblities to see what you guys think...

Does the 701 engine vibrate a noticeable amount more than a 650?

Maybe I should just ride the dang thing and forget about it, but I hate to do that if something is up. The vibration is only noticeable at about 2300rpm. Above or below you don't feel it. Thanks for the help.
 
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