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Engine Seized


boman's Avatar
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Join Date: May 2001
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04-06-02, 04:40 AM   #1  
broken ring? ( Murray Pwr Trac)

Murray Power Trac
20 hp
Model- 460777 Type- 127701
Code- 9512105C

My son said he moved this tractor just a little bit, like from the shed ( winter storage ) to the carport. I'm not sure if it quit while running or just would not start after he checked the oil. I think he checked the oil, which barely registered on the stick, added oil, and started it back up. It went just a little piece and quit.

The motor is not completely locked, but does seem to be seizing. It is very hard to turn with the flywheel ( by hand ) with plugs in and/or out.

I checked the starter, it is not locking up, it just cannot turn the engine. I suspect a broken ring. Any opinions?

P.S. We even tried to pull it off to start it , no luck. Prop did more harm!

Tx for any response

 
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04-06-02, 05:23 AM   #2  
Several Possibilities

Hello: Boman

A cracked ring is always a possibility. Chances are the lower end parts {crankshaft & rod bearings} aren't damaged, since there was oil in the crankcase. However, the upper end parts, {wrist pin, valve rods & guides, etc.} may have scored, etc.

If the engine remained unused for a long period of time, moisture and condensation may have caused internal rusting, corrosion and or pitting. There may be evidence of trace amounts of water in the oil and or fuel.

If all the external parts are determined not to be binding, then the problem could be one of the above or the rings have scored the cyclinder walls, etc. If any of the above is suspected to be case, the engine will have to be torn down to located the exact problem cause.

The other resident small engine service and repair professionals and moderators, may have alternate advice & opinions. Check back several times for additional replies.

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During installations of some parts which may not fit exactly perfect, it may be necessary to apply "BRUTE" force in order to compel compliance......... {....just humor folks... }

 
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04-06-02, 05:34 AM   #3  
During installations of some parts which may not fit exactly perfect, it may be necessary to apply "BRUTE" force in order to compel compliance.........

THATS scarey! If my son sees that, I'm sending you the bill, Tom! Just a little humor back at you! LOL

I may be as bad as he is, trying to tow start seized motor!

I am windering what extra damage we may have done in trying to tow this thing. Scoured cylinder walls, etc. Guess it depends on where the problem is.

Tx for the quick response

 
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04-06-02, 07:16 AM   #4  
bwiesner
I doubt broken rings are your problem. You more than likely have a gaulded bearing. At any rate the safest thing to do is to tear the engine down and find the problem. Black or blue places on the rod and wrist pin indicate lack of lubrication. Gaulded areas on the bearing surfaces indicate lack of lubrication. Later Butch

 
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04-07-02, 08:04 PM   #5  
Before you tear the thing apart, check your belts, and make sure they arent engaged or tight on the crankshaft pulley for any reason. The starter drive gear can become loose on the bendix and bind up the works too, it happens quite often. When this happens, it usually sticks there, making it hard to turn by hand too. If, when you checked the starter, it was removed from the engine, then you wouldn't have noticed the bendix problem. Check to be sure the gear is disengaged from the flywheel before you turn it by hand.

If you check these things out and still have problems, then start taking things apart. The heads can be removed for cylinder inspection while the engine is still mounted to the frame. That would be the next step in finding the problem. Keep us up on your progress!


"Who is John Galt?" - Ayn Rand (Atlas Shrugged)

God bless!

 
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04-07-02, 10:40 PM   #6  
The first thing I checked for was a sticking starter while still on motor. I have had them to go bad on the nose and stick in the fkywheel. Not the problem here. My other son has 17 hp that doing just about the same thing. Heheh, he called and said he put oil in it and , I think put a little oil in the cylinders, turned a few times . It went "kachink" and "freed right up". Had fire and was getting gas, still no start. I kinda figured I might should go over and have a look, especially when he told me the kachink part.
When I got there, I told him the sound he heard sounded to me like something broke or was trying to bind and that he probably needed to take the motor apart to check it. This a very nice mower with little apparent use that was given to him. I asked him if it had oil in it when he cahnged it. No! I noticed when I tried to crank it, the motor seemed to coast to a stop. Okay, no compression maybe. Had him to remove the heads to see if we could see if maybe a ring was broken, valve stuck open, etc. Sure enough on valve was stuck open and had to be pushed to close on one cylinder. The other cylinder has no piston action. I told him I thin we just found what made the kachink sound he heard. I'm thinking busted rod cap. While this son is somewhat machanically inclined, the other has no idea about things like this. I have been inside a few and can usually, by paying attention and asking guestions figure them out. So I guess, I have two to tear down and learn with them. Nothing like some good bonding father/son time! Heheh, wish us luck. Oh, and don't leave town, may be needing more help before this is over!

Tx

 
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04-08-02, 06:02 PM   #7  
LOL...we'll be here. Have fun! I enjoy building engines when I have the time to do it without feeling rushed.


"Who is John Galt?" - Ayn Rand (Atlas Shrugged)

God bless!

 
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05-10-02, 04:18 AM   #8  
success, I think

While waiting for son to get home yesterday, I thought I would take another look at his mower since I had some tools with me. Just happened to have my tool pouch with me as I had been to my building near him where I keep some appliances.
Thought I would take the heads off to see if maybe I could see a broken ring or scouring, etc.. I took one head off and did see some particles in the cylinder (hopefully just carbon). I wiped it out and let it turn a few times with the starter to blow the rest out, which it did just fine with no compression to keep it from turning. Put the head back on and it would intermittently turn with the plug out. I'm thinking at least it is not locked up or seizing now! He came in and we put the booster cables on it and it started and ran fine. I don't understyand why it quit on him in the first place while running like it did. Is it possible it was vapor locked and the battery or starter was damage/weakened trying to start it? By th eway, i do not understand vapor lock either. Have read about it, but it has been a long time. I thinought you could lay a wet rag across the engine to help that condition.
Anyway, unless it was trying to seize, it seems to be back to normal now. Tx for the responses.

P.S. Now if I can just get my other son's rider going. More involved prob there, no piston movement on one side. May need more than my tool pouch if we tackle that one. heheh, have a good day

 
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05-11-02, 12:52 AM   #9  
I don't see any way that a small engine could lock up by means of a vapor lock. I wonder if maybe the starter has problems. The upper armature bushing is bad about wearing out on these 2 cyl engines, and it causes intermittent starter problems. If the engine happened to flood enough to fill a cylinder with gas, that would lock the engine too.

I guess you know you have a broken connecting rod in the other engine you mentioned. Have fun with it!


"Who is John Galt?" - Ayn Rand (Atlas Shrugged)

God bless!

 
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05-11-02, 04:48 AM   #10  
http://forum.doityourself.com/showthread.php?threadid=87694&goto=newpost

Yep! Sticky valve too! Heheh, know how some people buy these things and just run them? No, I mean no, maintenance? This mower was given to him by someone who, I think, just put gas in and run it til it guits, buy another one. May not be too much too fixing it, if the cylinder walls are not scoured, crank ruined, etc.. Gonna be interesting to get into it.

 
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