520H seized

[petermil12833 16]

Well here goes my lament. My Onan P220G has seized without warning. No big noise. 600 hrs. Plenty of  new oil. 30 seconds before it died, the oil pressure light flickered on and off. Then it just stopped abruptly and won’t turn. I can’t try to tear it down until my barn warms up in the spring, but I’d appreciate any thoughts about what to look for first.

 

I thought I was well prepared for winter in the northeast (see pic). I still have my 314H that has served me so well for 25 years. I had completely rebuilt the snowblower attachment – new bearings, chain, paint, and even a transplanted auger from an older blower. Plus, I now had the 520H that I had acquired over the summer. After a good cleaning, a new fuel pump and voltage regulator, new oil and filters in engine and transmission, it has been running perfectly – sounding happy. Til about Feb. 1.

 

There was no knocking or pounding and it didn’t sound like something wanted to escape from inside. But it sure did stop – fast. The only clue was that oil pressure light, but these lights have been unreliable and I intended to troubleshoot all of them in the spring. Too late.

 

Any suggestions about where to look first? Thanks very much!

Peter

 

 

[Snoopy11 5,718]

Well, it is very hard to tell what exactly it might be. I realize that there wasn't a loud sound... to me it sounds a bit like a broken rod... but my first suggestion I would have is to use a borescope and poke around in the engine...

 

A broken cam would cause it to die suddenly, but shouldn't cause it not to rotate.

 

Could also be a broken cam gear...

 

SOOOOO hard to tell...

 

If the engine doesn't rotate at all, it may be that one of the main bearings failed... 

 

Im'ma keep thinking about this one.

 

30 minutes ago, petermil12833 said:

won’t turn

Certainly something broken....

 

Don

Edited February 14, 2022 by Snoopy11

[Maxwell-8 4,367]

Take the sparkplugs out, can you still not turn around the engine by hand?

[Snoopy11 5,718]

Just now, Maxwell-8 said:

turn around the engine by hand

Forward AND reverse rotation. Important to know if the engine will roll back but not forward... or not move at all.

 

Don

[stevasaurus 23,277]

@Snoopy11  Don, just a suggestion, but why don't you try editing your post to add the next thought you got 1 minute later.  It sure would make it a lot easier to follow.    Give it a try.

[Snoopy11 5,718]

Just now, stevasaurus said:

the next thought you got 1 minute later

No problem sir. Will do.

 

Don

[petermil12833 16]

Yup -- it sure could be any of those things. I do know that it won't rotate in either direction. I'll probably not know anything definitive until it warms up out there -- 18F today. THANKS!

[roadapples 6,983]

Sorry about the circumstances,  but

[stevasaurus 23,277]

Do you still have the blower attached...wonder if it could not be something there...maybe mule drive??  

[petermil12833 16]

No it's not the blower -- I've already transferred that back to my smaller 314H and cleared the most recent snow. It was not happy, because after sleeting all night, it was like blowing 4 inches of concrete. (Boy, I've grown to hate being on my back on the barn floor in the cold! )

[stevasaurus 23,277]

I used to love winter, now I love when those that like it get it.  Sounds like you have some experience, so I won't ask anymore about newB stuff.  I've had engines just get hot and seize, but if you shut them off right away, they will turn after they cool.  Got some good guys looking after you when you get warmer.  

 

Welcome to Red Square  

[Maxwell-8 4,367]

26 minutes ago, petermil12833 said:

No it's not the blower -- I've already transferred that back to my smaller 314H and cleared the most recent snow. It was not happy, because after sleeting all night, it was like blowing 4 inches of concrete. (Boy, I've grown to hate being on my back on the barn floor in the cold! )

Maybe it ran to long to lean, What do the sparkplugs say?

[petermil12833 16]

I'd used this tractor to mow for several months, then to blow snow after the first couple of small storms. On the day it died, I had run it for about 2 minutes and was 100-ft down the driveway when it quit. It was barely warmed up. That's why I'm baffled. Prior to that, it's been running strong and sounding fine. But until I can take it apart (ugh!) it's all conjecture.

[OutdoorEnvy 1,766]

Have you checked the oil for metal debris or you could drain it all out and see what's in it.  That wouldn't take long.  Also borescope camera's are pretty cheap, like around $25.  You could get one of those and check through the spark plug holes or the oil fill tube and see if anything is broke. 

 

Based on the short run time you described I'm wondering if the oil was too thick from being cold to be dispersed enough to make the cylinder walls and maybe it got hot a seized with the rings being under load with the blower.  If that's the case some marvel mystery oil or ATF soaking the head might free it up.   

[petermil12833 16]

Good idea - I will drain and inspect the oil on the next "warm" day, maybe Thursday. Should look good, because as I prepared the tractor for winter, I changed oil and filter -- probably has 4-5 hours on it. The blower load that day was light; I was just planning to clear 1-2 inch off the pavement so the sun could dry it out. It was also about 30 degrees. If the rings were dry, I would expect to hear that before it stopped. I'm thinking something inside just jammed. Thanks all!

[SylvanLakeWH 28,392]

 

Bummer on the engine but a lot of great ideas already… you’re in the right place!

[RED-Z06 2,567]

Oil pump gear could have sheared off, does sound like an oil sieze though, 30 seconds is enough time to do it.  

[squonk 43,799]

Sent you a link to an Onan repair shop.

[Bill D 2,247]

Try pulling the flywheel and checking to see if a magnet came loose and jammed in the stator. I've seen it before.  Maybe you'll get lucky.  Start on the outside and work your way in.

[petermil12833 16]

Oh, I like that! Maybe I will get lucky. Thanks.

[Bill D 2,247]

5 hours ago, petermil12833 said:

Oh, I like that! Maybe I will get lucky. Thanks.

Please let us know how you make out.

[wallfish 18,087]

On 2/14/2022 at 5:39 PM, OutdoorEnvy said:

Have you checked the oil for metal debris

Exactly

A quick easy place to start (even the cold barn) because if you find metal debris in the oil you can start pricing for a potential rebuild or replacement engine right away.

 

[petermil12833 16]

Today our temps got into the 40s, so I spent some time in the barn.  Here's my update. I drained and inspected the oil --- dragged a magnet through it to pick up any debris. On first look, I saw absolutely nothing. I wiped the magnet off and dragged it a second time. This time, I found a few (like 4-5) teeny tiny flecks -- almost invisible, but there. Now, I think an engine with 600 hrs might have a little something in the sump, right? After my first look, I concluded nothing to see here. After looking twice, I'd still say almost nothing.

Then I thought I'd try Bill's suggestion to look under the flywheel. BUT HERE I AM STUCK. I cannot remove the shroud from the engine.

I've got all the screws out, including those on the bottom, and the throttle/governor mount, the voltage regulator and ignition coil mounts. The shroud is now swinging loose, but there's one more fastener at the top near the back of the engine that I cannot see. Can someone tell me where to look?

Thanks!

 

[RED-Z06 2,567]

19 minutes ago, petermil12833 said:

Today our temps got into the 40s, so I spent some time in the barn.  Here's my update. I drained and inspected the oil --- dragged a magnet through it to pick up any debris. On first look, I saw absolutely nothing. I wiped the magnet off and dragged it a second time. This time, I found a few (like 4-5) teeny tiny flecks -- almost invisible, but there. Now, I think an engine with 600 hrs might have a little something in the sump, right? After my first look, I concluded nothing to see here. After looking twice, I'd still say almost nothing.

Then I thought I'd try Bill's suggestion to look under the flywheel. BUT HERE I AM STUCK. I cannot remove the shroud from the engine.

I've got all the screws out, including those on the bottom, and the throttle/governor mount, the voltage regulator and ignition coil mounts. The shroud is now swinging loose, but there's one more fastener at the top near the back of the engine that I cannot see. Can someone tell me where to look?

Thanks!

 

3/8 head bolt, goes in from the opposite side of the shroud near the center of the engine

Edited February 17, 2022 by RED-Z06

[petermil12833 16]

Thanks, I'll give it a shot. I knew I came to the right place!