- Location
- Sacramento Delta
What engine is this?
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Engine Symptoms
- Thread starter E350
- Start date
Mike W
Infidel
- Location
- North Florida
It’s a 701 61x cases
- Location
- Sacramento Delta
Thanks Mike. Can you also tell the year of manufacture?
waxhead
wannabe backflipper
- Location
- gold coast
What ski is it in
- Location
- Sacramento Delta
When my wife and I bought her 1994 Square Nose Super Jet I assumed (and the seller did not disabuse me of my assumption) that it had the stock 701 engine in it.
Well, when I eventually informed by a friend that it was, in fact, a Yamaha 650, I was pissed but it was too late to do anything with the seller but tell him that it was bullsh*t and that he was not reputable. I have since heard other bad stories about him.
So, in 2020 I bought this engine out of 1996 Waverunner 3 GP from @BIRDMAN here. @BIRDMAN is a great seller and great person to deal with. I have absolutely nothing bad to say about him.
But my wife's ski is now making a squeak when it shuts down. And last Sunday I was sure that she had broken a connecting rod. She had been running near WOT and it started making a racket.
But today I tested it and it has 160 psi in both cylinders and does not make any noise spinning with spark plugs out and starts and runs fine except that it makes a squeak when it is turned off. Inspection camera shows absolutely no cylinder scoring. I will post up photos in a bit.
I am cleaning up the 650 to put back in, if I need to rebuild this engine, but at this point I am wondering if it is an intermediate shaft bearing (but I had that rebuilt by JM about 6 years ago. But I guess it could also be a crank bearing but I don't know how to test for that.
P.S. I told my wife for the first time last Sunday that I had upgraded her engine to stock. She had previously noticed more power in 2020, but I told her I just tuned it. I didn't want her to be disappointed with her purchase and be as pissed as I was about the seller. When I told her, there were four other standup jet skiers on the beach who pitched in with their own stories about this particular seller.
Well, when I eventually informed by a friend that it was, in fact, a Yamaha 650, I was pissed but it was too late to do anything with the seller but tell him that it was bullsh*t and that he was not reputable. I have since heard other bad stories about him.
So, in 2020 I bought this engine out of 1996 Waverunner 3 GP from @BIRDMAN here. @BIRDMAN is a great seller and great person to deal with. I have absolutely nothing bad to say about him.
But my wife's ski is now making a squeak when it shuts down. And last Sunday I was sure that she had broken a connecting rod. She had been running near WOT and it started making a racket.
But today I tested it and it has 160 psi in both cylinders and does not make any noise spinning with spark plugs out and starts and runs fine except that it makes a squeak when it is turned off. Inspection camera shows absolutely no cylinder scoring. I will post up photos in a bit.
I am cleaning up the 650 to put back in, if I need to rebuild this engine, but at this point I am wondering if it is an intermediate shaft bearing (but I had that rebuilt by JM about 6 years ago. But I guess it could also be a crank bearing but I don't know how to test for that.
P.S. I told my wife for the first time last Sunday that I had upgraded her engine to stock. She had previously noticed more power in 2020, but I told her I just tuned it. I didn't want her to be disappointed with her purchase and be as pissed as I was about the seller. When I told her, there were four other standup jet skiers on the beach who pitched in with their own stories about this particular seller.
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- Location
- Sacramento Delta
I cannot post up photos from my inspection camera because it is a Micro SD card and I can't find my adapter to full size SD card.
However, I can describe an unusual thing I saw in the front cylinder.
The top of the front piston had some fresh shiny "dings" in the very center where the spark plug is located above.
I am wondering if there is some "piston slap" due to excessive slack in either the piston wrist pin or in the piston rod bearing where it attaches to the crank shaft?
Is there any way to test for this with the engine in the ski?
However, I can describe an unusual thing I saw in the front cylinder.
The top of the front piston had some fresh shiny "dings" in the very center where the spark plug is located above.
I am wondering if there is some "piston slap" due to excessive slack in either the piston wrist pin or in the piston rod bearing where it attaches to the crank shaft?
Is there any way to test for this with the engine in the ski?
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Quinc
Buy a Superjet
- Location
- California
If you move the engine forward a hair, see if you can move the midshaft by hand. It could be the bearings/seals are bad in the midshaft and or pump. Or even the wear ring on the pump starting to warp and making the sound?
Mike W
Infidel
- Location
- North Florida
If there is a way to tell I don't know. But those are 61X cases. Otherwise, they would be marked "6M6" I believe. The cylinders will be marked with 61X.
WFO Speedracer
A lifetime ban is like a lifetime warranty !
- Location
- Alabama
If you are asking if the spark plugs can contact the piston , there is no way for that to happen with the large bathtub style dome Yamaha uses , even if it had BR8ES plugs in it , still won't happen , now if pieces of the rod bearing or crank bearings get loose they can come up through the transfer ports and bounce around before exiting the exhaust.
IMO at this point just tear down the top end and see what is really going on , truefully I would tear the whole thing apart and inspect the crank bearings , install new crankshaft seals and go from there , I am quite sure this is not the advice you wanted to hear but it is good advice regardless , used engines are like a box of chocolates , you never know what you are going to get.
These engines are not that complex , one time I rebuilt two 650 -6M6 engines , reinstalled them and had both skis running in one days time in two Waverunner LX's .
- Location
- Sacramento Delta
Front cylinder:
- Location
- Sacramento Delta
Rear cylinder:
- Location
- Sacramento Delta
I won't pull the cylinder(s) until I put the Yamaha 650 in my wife's ski.
But out of curiosity, where can you buy a new Yamaha 701 oem crankshaft assembly for a decent price?
Better than Partzilla.com:
But out of curiosity, where can you buy a new Yamaha 701 oem crankshaft assembly for a decent price?
Better than Partzilla.com:
- Location
- OR
Jeff Seabold at Competitive crankshafts in Idaho. https://www.facebook.com/competitivecrankshafts/
DylanS
Gorilla Smasher
- Location
- Lebanon Pa
Looks like some carbon deposit just flaked off there in the picture to me.
Plus 2 on the midshaft.
My ski doesn’t audibly squeak when I shut it off but if I turn the engine over by hand I can clearly hear a squeak coming from the midshaft seal. Try running the engine disconnected from the midshaft/driveline and shutting it off and listening for the same noise to rule out a driveline squeak?
Plus 2 on the midshaft.
My ski doesn’t audibly squeak when I shut it off but if I turn the engine over by hand I can clearly hear a squeak coming from the midshaft seal. Try running the engine disconnected from the midshaft/driveline and shutting it off and listening for the same noise to rule out a driveline squeak?
Quinc
Buy a Superjet
- Location
- California
Oddly the 64x crank is normally cheaper (and the same) But I would go with an SBT crank from JM. I am running them on high compression/timing engines and haven't had any issues with them.
- Location
- Georgia, USA
I was chasing a high-pitch squeal from the rear of mine. I also checked my mid-shaft bearing. What I found was a loose pulse line fitting that was making the noise.
Big Kahuna
Administrator
- Location
- Tuscaloosa, AL
I use to have a squel. Never worried about it.
- Location
- Sacramento Delta
I took of the coupler cover, took the spark plugs out and spun the coupler/engine back and forth by hand:
1. It felt good, no resistance and the midshaft bearing felt good.
2. The engine itself felt like the piston wrist pins were loose. Is it supposed to makes this noise while rocking the coupler back and forth by hand?
rumble.com
rumble.com
3. For comparison, known good 1993 Yamaha 650 while rocking the coupler back and forth by hand:
rumble.com
rumble.com
1. It felt good, no resistance and the midshaft bearing felt good.
2. The engine itself felt like the piston wrist pins were loose. Is it supposed to makes this noise while rocking the coupler back and forth by hand?
1994 Yamaha Super Jet 701 61x - video 1
Is the engine supposed to make this noise while rocking the coupler back and forth by hand?
rumble.com
1994 Yamaha Super Jet 701 61x - video 2
Is the engine supposed to make this noise while rocking the coupler back and forth by hand?
rumble.com
3. For comparison, known good 1993 Yamaha 650 while rocking the coupler back and forth by hand:
1993 Yamaha 650 - Video 1
Known good Yamaha 650 engine noise while rocking the coupler back and forth by hand for comparison.
rumble.com
1993 Yamaha 650 - Video 2
Known good Yamaha 650 engine noise while rocking the coupler back and forth by hand for comparison.
rumble.com
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WFO Speedracer
A lifetime ban is like a lifetime warranty !
- Location
- Alabama
All this external sleuthing you are doing is great , wonderful , fabulous and all of that , it is getting you absolutely nowhere .
- Location
- Sacramento Delta
Well not entirely nowhwere. I am almost through installing my known good Yamaha 650 in the ski.
And the other engine is out and on the table for disassembly . . .
Updfate: 650 is in and running. So, now we have three functioning skis.
My wife and I will ski tomorrow, but probably with the FX-1 and 2019 SJ.
And the other engine is out and on the table for disassembly . . .
Updfate: 650 is in and running. So, now we have three functioning skis.
My wife and I will ski tomorrow, but probably with the FX-1 and 2019 SJ.
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