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Engine Seizure


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01-18-04, 03:30 PM   #1  
FazTaz
My Tecumseh Engine (snowblower) frooze, can't start it, or turn it over??

Hey all I have a craftsman 7 HP Two Stage Track Drive Snow Thrower model #247.885570 w Tecumseh engine. While I was doing my driveway (the last 10 sq feet) the snowblower started to produce a blackish smoke that was coming from a hose beneath the muffler. I stopped the auger and let the motor idle for a while. About 10 sec later the motor just made this weird sound and stopped. I check the fluids and there was enough gas, the oil was on the low side however (don know how that happened because I checked it 2 weeks ago).
The motor seems to be frozen since I cant turn it over. I cant pull the starter cord at all (as if it or the motor is stuck). Does anyone have any suggestions as to where I should go from here? The only thing I can come up with is the oil level was too low and the motor was not properly lubricated. Other than that Im clueless?? Last season my gasket blew, now this, I hope this can be easily fixed and the unit will be trouble free for at least a couple years.

The unit was serviced recently, new plug, oil, and carb. I add fuel stabilizer to every tank of gas. The unit was last used 2 weeks ago and ran fine.

Any help would be greatly appreciated!!

 
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01-18-04, 05:45 PM   #2  
If I were you I would check your fly wheel key first. I believe if that is sheerd, you can not get it to turn over. Am I right Cheese. Let us know. But in the mean time, check you fly wheel key and make sure it is in one piece.

 
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01-18-04, 06:06 PM   #3  
FazTaz
Term good thinking never thought about that, does anyone have a link to the manual for these engines? I forgot where I put my last one? Thanks!

 
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01-18-04, 07:21 PM   #4  
FazTaz
I hope what I'm about to say is totally wrong but if you have an electric starter on that motor, remove it and check the block directly behind it. There is the (shudder) possibility that you threw a rod and if it did, the block will have either some pretty big cracks or a hole in it.
The motors that I've worked on that threw rods were always on that side of the motor.
Like I said before, I hope that I'm totally wrong on this one.Keep me informed.

snoman

 
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01-18-04, 07:50 PM   #5  
FazTaz
Snowman I have an electric starter so Im about to do what you just suggested, please keep your fingers crossed for me!

 
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01-18-04, 08:03 PM   #6  
I 've worked on small engines most of my life.
From reading what you described, you blew the connecting rod.
Which most likely caused internal damage. In which, it's a good bet, that you will need to replace the block and all internal parts.
It would be best to get a short block, and switch all external parts to it.

The best way to go.

 
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01-18-04, 08:06 PM   #7  
FazTaz
Snow guess God was in my favor so far, no cracks on the block. I don't notice anything else so far, but I really haven't removed the head or anything else. Im gonna check the flywheel key next, any other suggestions. Im just a student with limited experience on engines (but love working on em, so Im not too pissed when they break), but I'll need everyones help in guiding me through! Thanks again guys!

 
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01-18-04, 08:38 PM   #8  
FazTaz
Checked the flywheel key, it appears to be intact (should some of the key be visable outside of the flywheel, because I don't see all of it). I can turn the flywheel clockwise and counter clockwise, but it gets stuck at a certain point and refuses to move

 
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01-18-04, 10:48 PM   #9  
Hello FazTaz!

Sounds to me like the engine seized. The flywheel key won't matter as far as the engine turning over...it will turn even if it is sheared. The connecting rod is not broken since the flywheel will not spin freely. This is good news. The piston probably seized in the cylinder...or the rod may have galled on the crank, but it sounds more like the piston seized.

When this happens, pretty much all you can do is fill the engine with oil, remove the spark plug, and squirt an ounce or two of oil in the spark plug hole. Then, with the spark plug still out, turn the flywheel back and forth, a little farther each way, until the engine rotates freely again. Then reinstall the plug and try to start it. If it starts and runs well without knocking or making strange noises, you'll probably be ok. If it knocks, then shut it off immediately before the rod does break and ruin the block.

It will smoke for a moment until the oil in the cylinder burns off, but if it smokes for more than a minute or two, you have piston and/or cylinder damage. Removal of the head will tell how extensive it is. I have done this many times and the engine turns out to be fine, but on occasion, it doesn't. Hopefully yours will be ok.

Let us know what you find!


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

God bless!

 
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01-19-04, 05:34 AM   #10  
FazTaz
Cheese thanks again for the help, last year you were a great help in diagnosing a gasket problem. Should I overfill the engine with oil, or just to the recommended level. Also is there a specific oil you would recommend in NJ weather. I've been using 5W30 (non-synthetic).

From my understanding synthetic doesn't have any or as much detergents as regular formulated oil, so it wont be as effective in such an application?

 
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01-19-04, 06:09 AM   #11  
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Hey cheese I did one better I removed the head, put some oil in the clylinder and started to move the flywheel back and fourth. The exhaust valve is lifting fine, the intake valve will rise a little, but not all the way (since I cant turn the flywheel freely) and the piston is moving up about 1.5-2" but it freezes in that position and wont move down or up any more, if when I turn the flywheel. I can use the butt of a screwdriver to push it back down and then turn the flywheel to push it up 1.5" again, but thats about all she'll go. Does that sound like a broblem with the connecting rod?

 
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01-19-04, 06:54 AM   #12  
Its broke get a new one

 
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01-19-04, 07:04 AM   #13  
My Two Cents

Hello: FazTaz

If you cannot visually see score marks on the cyclinder walls and the piston will not travel through one entire revolution, chances are the rod bearing or wrist pin bearing are damaged.

Could also be a scored or damaged crankshaft side bearing, shaft gear, the governor or the gear drive to it, etc. Most likely have to remove the crankshaft side cover to inspect for damage.

Based upon the info your provided so far and the info provided to you thus far. Pull the side cover off and be careful not to damage the end seal, if possible. Sand off any rust on the shaft, lube it and than remove the cover. Obtain a repair manual.

Generic small engine repair manuals have specific sections by brand name and some have sections by specific models. The back sections of these generic books often list book retailers that market specific brand and model service and repair manuals.

Check the local book stores, auto parts stores and the large world wide chain book stores online. Libraries should have books on the subject.

Small engine repair parts, generic repair manuals and additional help are all available at all local small engine repair shops and or lawn mower repair shops in your area. Shops and dealers are listed in the phone book directory.

Regards & Good Luck. Sharp Advice.
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01-20-04, 04:24 PM   #14  
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Hey guys took the unit apart, the connecting arm broke from where it attaches to the crank. The shaft of the arm is also bent and cracked. What could have caused this? The oil is dirty, very thick and black. As expected metal bits are inside the block. Aside from replacing the rod, anything else I need to replace or check so that this happens again.

Im ordering a new rod, new gasket set, and a installing a new plug. Gonna lube all the moving parts. Any other suggestions would be greatly appreciated!


Last edited by FazTaz; 01-20-04 at 05:50 PM.
 
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01-20-04, 06:33 PM   #15  
Good call to those who said it was broken.

The low/dirty oil did it. Are you the one who recently serviced it? What I'm getting at is if it was recently serviced, the oil should not be dirty and low, unless the engine has other problems as well. Maybe if you took it somewhere to get it serviced, they overlooked it (didn't change it).

I would not just replace the rod. If the oil was new, and it got low and dirty that quick, then you probably need rings at the least. Check the piston ring end gap and ring surface condition. I reccomend replacing them. Check the cylinder. If it has any scratches...enough to feel with your fingernail...then it needs work too. Look at the piston. If it is scratched up pretty well, then it will need to be replaced as well. Honing of the cylinder is NECESSARY if the rings get replaced (if the engine has a cast iron cylinder/sleeve). There are lots of things to look at. Measuring these parts would definitely show what items are worn and which ones aren't. Does the cylinder have a ridge? Do you have torque specs for the rod bolts? Head bolts?


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01-20-04, 06:56 PM   #16  
Faztaz
Sorry to hear about the rod but one VERY important thing to look at closely before you undertake in the rebuilding is check the area where the con rod bolts to the crank. If it is not perfectly clean, it will have to cleaned. Most likely before the rod let go, some of the aluminum from the rod heated up quite hot and melted on the crank. If it isn't cleaned perfectly, then you run the chance of having the bits of aluminum on the crank tearing up your new rod and costing you lots more money. I believe that your local small motor place will have an acid that will take aluminum off the crank.

snoman

 
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01-20-04, 07:01 PM   #17  
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Cheese the piston looks good, but I was planning on replacing the rings anyways (and possibly the piston as well). I have all the torque specs and a torque wrench.

Sno you are very right. I was actually going to ask about that. I didn't know if I needed a new crank or it could be cleaned. I'll check with a local machine shop.

Does anyone have any clue as to how much labor might run to have all this put back together. Im in the hospital everyday with very little free time, I get up at 5 and come back at 11. Today I was lucky and got home early, but its rare. If its not too much $$ maybe I can have a pro fix it for me!

 
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01-20-04, 07:08 PM   #18  
Faztaz
I'm not sure what the labor rate would be but you should also look at getting a price for a short block. All you'd have to do then is put all your exterior parts back on. (carb, flywheel, ignition, etc)
At least then you have 2 prices to play with.

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01-20-04, 09:58 PM   #19  
I agree...you'd probably come out better $$ wise with a new short block. And this way it's a new engine, not rebuilt. I forgot to mention the crank. Acid will remove the aluminum. Make sure the crank didn't get bent or marred.


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01-20-04, 10:05 PM   #20  
FazTaz
Im gonna check with sears tomorrow about the short block, I was thinking the same earlier on if the price of the piston and rod was too much $$. Its almost close to 100 with everything said and done, and short block with new valves, etc, would be easier. Does a short block also include the flywheel? Also if you know of any places where I can purchase one for a good price, please limme know! Thanks again guys. God Bless!

 
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01-20-04, 10:51 PM   #21  
hehe...gonna get a rise out of some people here, but an alternative measure to using acid to remove the aluminum is getting yourself some oven cleaner and a small propane torch....heat the crank up with the oven cleaner on...(don't make it red hot) but just very warm....then you can take some fine grit sandpaper and most of the aluminum will just fall off....the process may need to be done more than once...this method also works on cylinder walls..

 
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01-21-04, 03:48 PM   #22  
faztaz
A shortblock does not come with the flywheel,carb and manifold,cylinder head or ignition. Basically it is all the internal parts (brand new) only. I would check a few small motor parts to see what prices they come up with. In order to get the proper one though, you must provide the model, type and serial number off your engine. In your case since it's a Craftsman, it will be a 9 digit number probably starting with 143.XXXXXX.
Good luck.

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01-21-04, 05:45 PM   #23  
FazTaz
Sno thanks I knew about the ignition, head, etc, but some of the short blocks apparently come with a flywheel. I ended up purchasing it from Sears. Managed to get a slight discount fron the lady so I eneded up spending $200 for the block and $10 for the gasket.

 
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01-21-04, 06:43 PM   #24  
faztaz
Good to hear....soon you'll be back playing in the snow again.

snoman

 
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01-21-04, 06:53 PM   #25  
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I sure hope so, guys again thanks for all the help, I'll keep you updated. A couple questions though the spark plug was pretty fouled (a lot of carbon deposit), the valves were also charred, as was the piston head. Is this normal (I know the plug shouldn't be, do you think it was because of the broken rod, or possible too rich a mixture?) Secondly whats the best type of lubrication (oil) to use so I can prevent future problems. 5-30 or 10-40? Also should I stick with crude or switch to synthetic?/

 
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01-21-04, 08:36 PM   #26  
The deposits on the head, piston, and valves is probably carbon buildup from burning oil, caused by bad rings. (since you must have been burning oil and had blowby for the oil to be low and black in a short amount of time). I would say use either straight 30 or 10W30 if the weather gets too cold for straight 30, and conventional oil works just fine as long as it gets changed when due.


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01-22-04, 03:46 PM   #27  
faztaz
When I do a servicing on a blower I always use a good quality 5w30 oil. (castrol, veedol,quaker state etc) As for synthetic, that is usually up to the owner of the machine. Some people swear by it and others don't. The oil weight that cheese says is correct but up here it usually hovers around -20C and then with the windchill (oboy!) I want an oil that won't be too thick when I try to start it.

snoman

 
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01-22-04, 08:24 PM   #28  
I use synthetic in just about everything here. The new Briggs manuals even says that you can use synthetic over a much wider temperature range than any other kind of oil. I use it in my vehicles as well. So far I've never had a problem with anything due to oil. When it's below zero the oil has to flow to work and it can't flow when it's too thick. Synthentic won't change viscosity nearly as much with a temperature change as most other oils. You aren't 'usually' blowing snow when it's way below zero because the air is too dry to snow, but you sure drive your vehicles.

 
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01-22-04, 08:45 PM   #29  
FazTaz
Doesn't synthetic omit the detergents that are found in regular oil. Are these really needed in a new engine? Also if I were to go synthetic should oil changes still be performed every season, or can I go 3 years without having to change the oil.

Also should I use a regular sears brand spark plug, or should I get something of higher quality like NGK, Bosh, etc?

Also when installing the short block, how do I know how to line up the gears on the camshaft and crankshaft gears? Are there timing marks on them?

 
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01-23-04, 05:15 PM   #30  
I think that I would continue to change my oil every season. For one thing, if you decided that you could get away with changing your oil every three years you would probably get out of the habit of changing oil and not do it at all. Besides the little bit of oil in a small engine doesn't cost enough to make price a factor.

Lawn mower engines operate in a dusty enviroment and the oil has the job of holding that grit in suspension. Just getting that grit out of your engine during a regular oil change is a good thing. Even the best oil can only hold so much. The main thing with synthetic oil is its ability to not thicken too much when cold and not thin too much when hot. It will maintain its flowing ability under a wide temperature range much better than a non synthetic oil. Air cooled engines (like in a lawn mower or maybe in a VW beetle) run a lot hotter than your typical car engine so you need an oil that will perform well with big changes of temperature. Think of the big temperature changes that face a snow blower engine when it's started on a cold winter day. It's a testment to the technology that they can hang together. A good oil is just part of that equation.

I wouldn't worry too much about the detergent question. A detergent may help your oil keep the grit in suspension, but its main function is to keep too much sludge from building up. If you change your engine oil every 25 engine operating hours you aren't allowing much of that to happen. Besides, I think sludge is created from operating an engine while its cold. Lawn mower engines come up to temperature quickly and are at full temperature before you are even a tenth of the way done mowing your lawn. I only drive my vehicle about 10 minutes (on a water cooled engine) to get to work and the engine oil really doesn't come up to temperature before I shut it off. Here is where a good detergent oil will keep the sludge from accumulating under the rocker arm covers and other locations that will block the free flow of oil.

As for spark plugs, Sears probably doesn't make spark plugs. They probably have a major manufacturer make them and put the a Sears part number on them. I would go with whatever is cheapest and/or easiest to get.

Don't worry about the timing marks on a short block. They will have them. There is usually a dot on the crank shaft gear and on the cam shaft gear. You just arrange the gears so the dots are opposite of each other.


Last edited by jughead; 01-23-04 at 05:43 PM.
 
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