Why do engines lock up?

[JayinNY]

Was thinking about my one ATV, it's a 1992 I think Yamaha blaster, wish I had bought a banshee as in pic, anyway I started my blaster about 3 years ago, after cleaning carb ect, it's been sitting in my lawn shed for 18 years, I also have a Honda four trax 4x4, I really have no use for the sport atv as when I was younger. But I want to keep it as nothing is 2 stroke anymore!! I went to kick it over and to my surprise it's locked up? Ticked me off why would it lock up just sitting inside? I hardly rode this atv, lucky if there's 50 hrs on it, I'm gonna take either the tractor or the Honda Atv and see if I can pull it to free it up, I'll pull the plug and pour some oil down the cylinder,
Why do engines that sit sometimes lock up? Wish I put oil down the cylinder befor I let it sit, my farm all H has been sitting for a few years too, wonder if that's locked up too!

 

[ghostdncr]

I'm not sure what the correct term would be but in many cases, I think it's just from the oil "drying out" or whatever it is that happens to oil when it sits idle for long periods of time. I broke a four-cylinder engine loose like that that just recently. It was locked up good and tight but I pulled the plugs and gave each cylinder a five-second burst of 3-in-1 penetrating oil. Let it sit overnight and it easily broke loose the next day and started spinning like nothing was ever wrong.

 

[Mutt and Jeff]

rust never sleeps
.
.

Corrosion of any metal is a natural process. It results in the conversion of the metal into its chemically stable form that can be either oxides or
hydroxides or sulphides.
Rusting is a type of Chemical Change. It results in the formation of Iron Oxide which is an entirely new substance. Chemical Reaction of Rusting is as
follows:


Iron + Oxygen (from environment) + Water (Humidity) ?> Iron Oxide (Rust)
Fe + O2 + H2O ?> FeO and Fe2O3

Iron occurs naturally in two different forms: Iron (II) and Iron (III).
Scientific Name of Oxide of Iron (II) is Ferrous Oxide (FeO).
Scientific Name of Oxide of Iron (III) is Ferric Oxide (Fe2O3).

...

Corrosion
Metals can oxidise in air. They react with oxygen and form metal oxides. For example, sodium is a very reactive metal.

When sodium is cut or scratched, its freshly exposed shiny surface rapidly turns dull as a thin layer of sodium oxide forms:

sodium + oxygen → sodium oxide

4Na(s) + O2(g) → 2Na2O(s)

Other metals may oxidise more slowly. Gold and other very unreactive metals do not oxidise in air at all.

Corrosion happens when a metal continues to oxidise. The metal becomes weaker over time, and eventually all of it may become metal oxide.

Rusting
Rusting is a specific example of corrosion, which occurs when iron or steel reacts with oxygen and water:

iron + oxygen + water → hydrated iron(III) oxide

Hydrated iron(III) oxide is the orange-brown substance seen on the surface of rusty objects.

A rusting experiment

The experiment in the diagram shows that both oxygen and water are needed for rusting to happen.

Three sealed test tubes, iron nail. 1st: nail half-submerged in water. Air. Nail rusty. 2nd: nail submerged in boiled water, layer of oil. No air. Nail
shiny. 3rd: nail on silica gel. Nail shiny.Calcium chloride (in the right-hand test tube) absorbs water
The nail only rusts in the left-hand test tube. It does not rust:

in the middle test tube, where there was water but no oxygen
in the right-hand test tube, where there was oxygen but no water

...


Colors and porous surface texture of rust
Steels and other iron?carbon alloy phases
FagerstaRA?2.jpg
Ferrite Austenite Cementite Graphite Martensite
Microstructures
Spheroidite Pearlite Bainite Ledeburite Tempered martensite Widmanstatten structures
Classes
Crucible steel Carbon steel Spring steel Alloy steel Maraging steel Stainless steel Weathering steel Tool steel
Other iron-based materials
Cast iron Gray iron White iron Ductile iron Malleable iron Wrought iron
vte
Rust is an iron oxide, a usually red oxide formed by the redox reaction of iron and oxygen in the presence of water or air moisture. Several forms of rust
are distinguishable both visually and by spectroscopy, and form under different circumstances.[1] Rust consists of hydrated iron(III) oxides Fe2O3?nH2O
and iron(III) oxide-hydroxide (FeO(OH), Fe(OH)3).

Given sufficient time, oxygen, and water, any iron mass will eventually convert entirely to rust and disintegrate. Surface rust is flaky and friable, and
it provides no protection to the underlying iron, unlike the formation of patina on copper surfaces. Rusting is the common term for corrosion of iron and
its alloys, such as steel. Many other metals undergo similar corrosion, but the resulting oxides are not commonly called rust.[2]

Other forms of rust exist, like the result of reactions between iron and chloride in an environment deprived of oxygen. Rebar used in underwater concrete
pillars, which generates green rust, is an example. Although rusting is generally a negative aspect of iron, a particular form of rusting, known as
"stable rust," causes the object to have a thin coating of rust over the top, and if kept in low relative humidity, makes the "stable" layer protective to
the iron below, but not to the extent of other oxides, such as aluminum.[3]

 

[Mutt and Jeff]

Maybe it really wasn't running when last parked.
maybe the "boys" had it out for a few runs and BLEW IT UP
maybe you can't remember why you parked it
maybe that guy that came over to buy it sabotaged it for a better price

Here....you tie this rope to it get on it and I'll (me and a couple laughing drunks) pull you with the truck (at about 50mph)

 

[jimg.allentown]

Depending on why it is locked up, pulling it to free it up will probably do more damage than you already have.

Pulling it is a good way to bend a connecting rod, break a crankshaft, or cause broken parts to do more damage than they have already done.

Maybe taking a more cautious approach would benefit the situation?

 

[Steve@Advance]

It's usually rust, the rings stuck to the cylinder wall.

But it can also be mud dobber or rodent nests jamming the flywheel. Even heard of mice stashing food in the cylinder, carried up the exhaust pipe!

Do some investigation first, don't want to cause more damage by forcing something. Also want to look the hoses and electrical over for rot and chewing.

 

[MSM]

Lack of preventative maintenance. Like you said...should have put some oil in the cylinder and maybe kicked it over when you walked past it. same with the tractor sitting, some oil in the cylinders and turn it over every once in a while. And make sure the exhaust is covered.How many tractor engines have been ruined for lack of a tin can over the exhaust.

 

[showcrop]

You didn't fog it before storing. Any two stroke needs the inside coated with the special clinging fogging oil before being stored for more than 6 months. your owners manual tells you that.

 

[ss55]

After 18 years of storage it will probably also need to have the carburetor rebuilt or replaced as all the gaskets and o-rings will bad or will soon go bad. Was the fuel tank drained when it was put into storage?

 

[Billy Shafer]

Good explanation. What people don't think about. When you let an engine sit to long. The oil drains off of the metal. Letting the rust move in.

 

[Mike(NEOhio)]

Could also be just that the gas flashed off leaving the oil behind to fluid-lock the cylinder. Did you try to turn it over with the spark plug out? My chainsaws will do that if they sit too long.

 

[SDE]

Humidity is moisture in the air. Condensation forms on the internal metal surfaces and cause the different metals to rust together. Any time it is hot enough to get the metal to sweat on the outside, it is also sweating on the inside.

 

[circus]

One way to lock up an engine is storing it damp or outside specially with parts missing. After not long a life form will take up house keeping in your cylinders and you'll be wondering "how did water get in there?"

 

[GEO-TH, In]

One very hot summer day I was running full speed on a Honda 305 when it locked up. It was like I applied back brake. Back wheel slid sideways. I pulled in on clutch, bike straighten up. I coasted to bottom of hill. Popped clutch, engine broke loose
Sounded like a diesel and smoked like one too. I had to get cylinders bored and over sized pistons.

I got engine too hot and pistons seized.

 

[old]

Any engine or for that matter any thing made of metal with 2 or more moving parts will lock up from sitting a long time. I've seen car engine truck engine etc. lock up just form sitting. One cannot stop condensation which equals water which equals rust which equals thing locking up. Only way to keep it form ever happening is a good coat of oil etc. In your case fill the cylinder with ATF and let it sit a week or so
NEVER try to pull a lock up engine as in with a car or truck etc. or you will end up with broken parts. Ring can and will break as will axles rods etc. due to being pulled. A starter on the other hand will not hurt any thing but push rods if valves are stuck

 

[Mule Meat]

I would not pull it. Risk to great for breaking the rod, busting the piston or worse.

Since they are so easy to remove from those air cooled engines. Pull the head and have a look. It will give you an idea of what the cylinder and rings look like. Rubber hammer or block of wood can help the piston to move.


Basically gave my 99 Banshee away to free up storage space. It was built with Toomey t6 pipes and all. Fast but trail rideable. Guy handed me $1200 and we loaded it up. Regreted it ever since.

 

[Mutt and Jeff]

They "lock up" to keep the bad guys out.
just don't forget the PIN
or you might find yourself contacting the Locksmith

 

[Geo-TH,In]

Condensation gets inside and causes rust. Condensation is more common in certain parts of the country when conditions are right following a temp/humidity change. Usually in February, I have those conditions causing condensation to get under the distributor on my 6 cylinder GMC truck. Good thing it happens when parked either in pole barn or Garage. Won't start in morning, time to change rotor and distributor.

Sea Foam makes a spray people use when storing boats over winter. Remove plug and spray foam in cylinders.

 

[Mutt and Jeff]

They are supposed to lock up
to keep the old man off of it
it's a safety feature

whaaaa whaaaa WHEEEEE whooops
busted bones

YZ400 all fresh first run 3rd gear was the last I remember

 

[fixerupper]

It could be more than just rust. The aluminum piston might have corroded between the piston skirt and cylinder wall after sitting that many years. The corrosion swells and forms an almost permanent bond.

 

[Den N Ms]

JayinNY.DON'T try to pull it to break it free,if you do you will break it and it won't be free to repair it.
Remove the spark plug and use a plastic straw to reach down the plug hole to determine where the piston top is in the bore.Chances are it is down and it got condensation inside from the exhaust ports being open is why it locked up.Anyway spray some PB Blaster in the hole with the red straw bent on the end to get the spray on the sides of the cylinder wall,ad some ATF or Marvel Mystery Oil if you want and screw the plug in a wew threads to keep trash out.Let it soak a week then try kicking it over.It it didn't come free ,pull the head and see what you have.Them sand the wall to remove rust with some 220 paper, use a block of wood and lightly tap it with a hammer spraying piston sides.