21 850 died a mile from the truck

[line8]

I’m not sure what to do with this sled. A little back story.
The Ring gear broke, well screws backed out and it flung itself off. It broke the pto check valve and the hose separating them.
I didn’t know at the time. But I rode the sled out about 8 miles under mostly light to occasional medium throttle. It Never heated up. The plugs looked good. Normal looking.
I decided to get a new check valve and I reattached the hose. I also injected about 8ml or so of oil into the check valve after installing it. I ran it many different times on a stand over the following week. No weird sounds, the clutch ran smooth, idled fine, 1750. Where it always idles.

I decided to take it out and ride it. I put brand new plugs in it. Started fine. Reversed fine. I Left the truck and it was running perfect. About a mile from the truck it just died on steady throttle. Temps were little over 100.
I checked the drive clutch and it spun by hand easily, like always.
I started it back up, it ran perfect. I Rode it another 100 yards and it seemed fine, but it was idleing funny. It Had a different idle sound to it and was about 1700.
I pulled the plugs.
PTO side was oily and looked a little tan on top, but was oily for sure.
MAG side was clean and still looked new.
Shut it down and towed back. I started it to load and it was 1 pull and sounded normal.
Got home with it, I checked compression. 120pto/124mag.

I’m a little worried I got air with the broken check valve. How do I know?
Is it possible the oil I injected fouled the pto side plug?
What should I be looking for, a little lost on what to do. Open it and look?
Obviously I’m thinking of the pto bearing or seal, and maybe it’s all fine but maybe it’s ready to pop???

 

[BeartoothBaron]

This could be a lot of things, but I can tell you that air in the check valve isn't likely to cause issues. Air in the lines or check valves (anything after the oil pump) will just get pushed through and you'll get normal oiling once that's happened. It's best to run the oil pump enough to clear any air bubbles, but as long as there's no air in the pump or line to the pump, there won't be any major interruption. There may be damage to the PTO bearing; crank runout is about the only thing you can check, but that could check out while the bearing is going. A fowled PTO plug would cause a loss of power and poor running, but it should still run on one cylinder. I don't think the extra oil you put in did anything. Could maybe be the PTO crank seal? I guess if it were me, I'd pull the Y-pipe and exhaust valves to get a good look at the cylinders, as well as checking runout. It could be be the crank or a cylinder going down, but it might also be something minor. I wouldn't tear the whole thing apart unless you find a solid reason to.

 

[line8]

I just decided to have a look at the compression again. I read it wrong the other day. It’s 124pto/128mag(just above sea level). But it does idle a little lower at 1650-1700(occasionally) after warmup at about 3-4000’.

I’ll pull the y pipe and have a look in there. Then see if I can get a crank runout read.
Any recommendations on a runout dial or just any? I suppose it could be you get what you pay for just like everything else.

 

[BeartoothBaron]

Just any dial gauge should work. The spec is something like not more than .0025 measured just at the start of the taper (closer to the seal), so gauge that reads in thousandths is good enough. That number isn't specific to the 850; it should be close, but I can't say for sure. I'd also turn it over by hand (with the clutch on) and see if you can feel any play or roughness, although that's probably a shot in the dark. You might not notice anything even if it is bad, and of course, it'll jump back and forth because of the magnets in the flywheel.

 

[line8]

Just any dial gauge should work. The spec is something like not more than .0025 measured just at the start of the taper (closer to the seal), so gauge that reads in thousandths is good enough. That number isn't specific to the 850; it should be close, but I can't say for sure. I'd also turn it over by hand (with the clutch on) and see if you can feel any play or roughness, although that's probably a shot in the dark. You might not notice anything even if it is bad, and of course, it'll jump back and forth because of the magnets in the flywheel.

Ive got a dial gauge I’ll be setting up this weekend. I have spun the clutch by hand and compared to my Matryx. Its the same, moves freely with no noises.
Thanks for the info, appreciated.

 

[line8]

Update on this.
Pto side went lean. MAG side looks alright.
Crank runout is good.
So, I’ll be doing some engine work. I’m leaning to blaming a bad pto bearing seal after the clutch ring gear broke off. It would probably be wise to check the injectors before new goes back in so i can rule that out.
Probably new engine, I don’t want this same headache next season.

 

[Griff]

Bummer. If you have to go much farther than pistons, injectors and seals probably worth a conversation about a Carl's 900 top end.

 

[line8]

Bummer. If you have to go much farther than pistons, injectors and seals probably worth a conversation about a Carl's 900 top end.

Interesting, I made a call to them today but didn’t get to have a talk.