Stuck Ring? Or something else?

[FyrHazard]

Hey guys, just got back from my second ride on my new-to-me 61x in my superjet. Haven't even gotten through my first tank of gas yet. I was WOT when the ski suddenly died - started up again but it turned over really slowly and would run well enough to limp back to the dock.

So I take it home and compression test it - 150 in the front, 25 in the rear :shooter3: It tested at 150 each when I got it.

Pulled the head, everything looked pretty good. Pulled the cylinders and found this! So what is this actually? Stuck ring? I checked the plugs after the first ride and everything looked good. The thing ran great too! It's a 61x with protec head, protec black pipe, and prok flame arrestor. Otherwise stock as far as I know.

Gonna do some searching for information on rebuilding the top end and getting the cylinders taken care of but I'm all ears if anyone wants to jump in on a good place to send them and where to get parts. Looks like I'll need pistons and a bore/hone. Anything else I should be checking into with carnage like this?

 

[redsxr800]

how cold was the water , maybe cold seaze

 

[suva]

how cold was the water , maybe cold seaze

That's what I would guess too.

 

[Matt_E]

If it were a cold seizure, you would see score marks on four corners of each cylinder.
It's hard to tell from those pictures.

 

[FyrHazard]

The water was somewhere around 50-60 degrees. Marks are only in one place on one cylinder. There was even a little dry spot on the top of the cylinder where the gases were going by.

 

[Matt_E]

Then I wouldn't think the seizure was temperature related.

Are you 100% certain the carb(s) is/are tuned right?

 

[blaster4life]

ouch....weant to subscribe 4 info

 

[Motorheads5]

The wash look's good.It's almost like debris went through the engine just guessing.

 

[FyrHazard]

Then I wouldn't think the seizure was temperature related.

Are you 100% certain the carb(s) is/are tuned right?

I am no expert when it comes to carb tuning, but the wash looks good and the plugs looked pretty good, and it ran great with no hesitations anywhere in the throttle range.

Would a piece of the reeds do this? I should probly tear the intake off and check them.

 

[Matt_E]

Broken reeds could have done it.

In my limited experience with foreign objects going through the engine, the head showed clear signs of getting hammered by pieces.

 

[FyrHazard]

That's what I was thinking too, and the head here looks perfect. That's what made me think stuck ring, but I really don't know what that looks like and can't find any good pics.

 

[Freakrider]

From Group K:

Lean seizures - Despite what most people think, lean fuel mixture seizures on personal watercraft engines is actually a very rare occurrence. The high speed circuit on almost all personal watercraft carbs is responsible for delivering fuel in the 30%-100% throttle range. If the high speed circuit is lean enough to cause piston seizure, it will also cause an almost un-ridable hesitation or laziness in mid-range throttle response. Dangerously lean high rpm racing motors can sometimes offer acceptable mid-range, however they will accelerate to peak speed very slowly.

The classic lean seizure exhibits heavy scoring and seizure along the entire width of the exhaust port with only light scoring on the opposite piston faces. In lean mixture conditions, the exhaust gas temperatures escalate quickly into the meltdown stage. Those high temperature gases can compromise or completely burn off the oil film on the exhaust piston face as the exhaust port is being covered up. With the oil film weakened or gone, scoring quickly turns into seizure and ring locking.

Air leak seizures - These are very common seizures because air leaks themselves are so common in watercraft motors. If you could pressure check every engine that showed up at a local racing event, you would find over 50% of them to have an air leak. Because of the varying degree of these leaks, some will result in seizure, others will only cause poor carburetion or slight overheating. The varying effects of these air leaks makes this a difficult diagnosis.

In any situation where an engine has seized for no apparent reason, the motor should be pressure tested before any other teardown work is performed. If a mechanic does not have the equipment to pressure test your seized engine, it's very unlikely that he will have the finesse to accurately diagnose your problem either. In fact, pressure testing should be a standard finishing procedure for any major engine reassembly work. Race engines should be pressure tested no less than every 20 operating hours.

The air leak piston seizure, depending on the severity of the leak, can look like a four corner type or a lean mixture type of scoring pattern. If an engine is operating on the ragged edge of overheating, a small air leak can easily cause the extra overheating that will result in a four corner seizure. On the other hand, a huge air leak will draw in so much additional air that even an over rich engine can experience a lean type seizure at full rpm's.

 

[blaster4life]

what tool do you use to do a pressure test?

 

[Matt_E]

A simple air pump and a pressure gauge, and some pieces of sheet metal to block off the exhaust and intake ports on the respective manifolds.

 

[QuickMick]

what Matt said. after blocking off your pipe and carbs. (I just put a piece of rubber between the carb and manifold, same goes for the manifold to head pipe.

Put gauge inline to your pulse fitting and pump up to 10 psi max

If anyone needs any 1/8" thick rubber I can mail you enough for two carbs and your b pipe.

 

[blaster4life]

Hmmmm anyone have pics of this set up....i love tools and would very much like 1

 

[Matt_E]

It's as easy as it sounds.
Block off the exhaust manifold hole.
block off the intake manifold holes.
If you have two pulse nipples on the cases, put the pump on one of them and the gauge on the other.
Pump up to 10 psi and wait 10 minutes.
It shouldn't leak down much (not sure how much is acceptable)
If your cases have one nipple, you need to tee the pump and the gauge together.

 

[blaster4life]

well that sounds easy enuf....not kit or anything ya build it yourself?

 

[Matt_E]

I built mine.
You can use a hand-bicycle pump, a cheap pressure gauge, and some rubber hose.

 

[blaster4life]

looks like i'm off in the morning to the hardwear store to get supplys........ i have a fealing i'm going to but upset when i hok this thing up to my 701 that was last rebuilt in 01.....LOL