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Damage from too much starter fluid?

This is not necessarily a car question, but is a general question on the effects of starter fluid.

I’m in the process of trying to get my 100 year old neighbor’s snow blower going for the winter season. I blow out his driveway, and his snow blower would be a backup to mine.

The snow blower is a 60s vintage Ariens with a 5 HP Tecumseh L (flat) Head.

His grandson was trying to get it running last year with liberal amounts of starter fluid. I warned him that he was going to blow the engine, which my father always told me would happen if too much starter fluid was used.

Today I replaced the spark plug, spark plug boot, fuel line, and gas. I’m getting both spark and fuel (the plug is wet when I remove it), and I can sometimes get the fuel to fire once.

I noticed, however, that every time I removed the spark plug, it looked like the piston was at TDC. I’m not familiar with flatheads, but I’m assuming that what I’m seeing through the spark plug hole is the piston.

When cranking the motor with the plug removed, the piston does not move. I cannot move it by pushing on it with a screwdriver. When cranking the motor with the spark plug in place, fuel blows out the air intake. The motor seems easier to crank than it did previously.

My question is this: Is it possible for overuse of starter fluid to cause internal engine damage? Based on the symptoms I provided above, what kind of damage might I be looking at?

The piston does not move? I’d say a motor with a non moving piston has no chance of running. Don’t waste any more time on this one. If you want to keep this snow thrower you’ll need to replace the motor.

Starter fluid is a mixture of diethyl ether (the old anesthetic), light petroleum distillates, and some kind of “top oil.” Generally, there are two complaints directed at use of starting fluid in small engines: insufficient octane, and insufficient lubrication for 2-stroke engines.

As for low octane, flat-heads typically have very low compression ratios, so one should be safe from pre-ignition. As for lubrication, a flat head (correct me if I’m wrong, please) implies a 4-stroke engine, which typically don’t mix the oil with the fuel (does the snowblower required mixed fuel/oil?)

To determine if the piston is indeed moving, remove the spark plug, and loosely place a finger over the hole as the starter cord is pulled. One should feel a “puff” of air escaping at TDC. If not, one has serious piston/valve problems.

You’re correct - it’s a 4-stroke engine. I’ll try your test in the morning. Thanks.

Excessive amounts of starting fluid, or ether, can wash the cylinder walls down very quickly and this can lead to low compression, which on a flathead is pretty low even on a good day.
This could be why the engine appears to crank over easier than it did previously; assuming the piston has not disconnected itself from the connecting rod of course.

Remove the plug and crank the engine over slowly just to verify that it’s going up and down.
If washed down cylinder walls is the cause try squirting a small amount of motor oil into the cylinder and then see what happens with it.

(I worked for a dealer once who had a pretty dumb lot man and one of his duties was to start every car on the lot in the morning to make sure there was not a problem. Ether was his best friend and one morning a very low miles Dodge would not start at all.
When cranked the engine would turn over very easily and a compression test showed all cylinders were about 50-80 PSI and at which an engine will not run. A squirt of oil in each cylinder, reinstalled the spark plugs, and it fired right up due to the oil helping to seal the rings up again. A followup compression test showed about 175 on all cylinders.)

Just an example to show you what ether can do to an engine and really, the only ones who should be using that crap are people who are trying to start a diesel on a cold morning, and even that’s a maybe.
In the case of the lot man I mentioned, I’d come in for work in the mornings and the entire lot would smell like ether. It was a running joke that if someone lit a cigarette up out there the entire dealership was going up in a fireball.

I would forget the back up idea. Leave the neighbor’s snow blower to the neighbor and don’t try to fix it. If he want’s it fixed let the shop fix it.

If something happens to it while you are trying to fix it YOU will be the one blamed. Be a good neighbor and take care of his snow, but don’t mess with a questionable machine. I see bad things if you do.

I appreciate the advice, Mr. Meehan. I’ve already told him that I think his snow blower is likely dead, to which he responded “Everything he (the grandson) touches ends up broken”, so I think I’m off the hook on this one. I told him I would tinker with it and see what I could figure out.

To ok4450 - when I remove the plug and crank the engine over, the piston does not appear to move, so it looks like the connecting rod is broken. Evidently, that is a common issue on the Tecumseh flat heads if poor lubrication comes into play. The fact that I cannot move the piston by pushing on it with a screwdriver tells me either the rings or piston skirt are damaged as well.

I think this one is a goner.

we use propane in our shop. and never ever use starting fluid on a rotary.

Eripp1 wrote:

I noticed, however, that every time I removed the spark plug, it looked
like the piston was at TDC. I’m not familiar with flatheads, but I’m
assuming that what I’m seeing through the spark plug hole is the piston.

Not necessarily. The spark plug is located just between the valves and piston. If you can look through the plug hole sideways with a flashlight, you should be able to see the piston. The link below should make the piston-plug location clear.,r:9,s:0

Did you try the suggestion of placing your finger over the plug hole while pulling on the starter cord, and checking for slight suction and puffing?

If pulling the rope causes fuel to spit out the intake there is a very good chance that the intake valve is sticking. You might remove the tappet cover and and spark plug and watch the valve while pulling the cord slowly. If the valve fails to snap back fully to the tappet the valve stem is sticking in the guide. That is a common problem with aging Tecumseh and B&S engines. If the valve stem is sprayed with WD-40 and pressed repeatedly against the spring and released until it snaps freely back. Of course, you must move the crank to put the camshaft in the valve open position. If the valve is stuck at the fully open position removing the carburetor allows spraying penetrant at the upper end of the stem and pressing the valve downward.

Good point Rod. I just reread the opening post and noticed his comment:

When cranking the motor with the spark plug in place, fuel blows out
the air intake. The motor seems easier to crank than it did previously.

I have freed up a number of stuck valves on these engines, though it was usually done by taking both the head and tappet cover off, and then using penetrating from there.

The broken connecting rod is probably why the engine does not start. The damage is age related. Change the rod and the engine may start. It’s always possible to damage an engine but it’s more likely that the engine will fall apart by itself before you get the chance to do anything major.

If the engine has a broken connecting rod, I don’t think the engine would fire as you reported. I think you have a sticking valve or a broken valve spring. I’ve seen small engines with broken connecting rods and the engine spins over very easily. I had a Kohler engine with a broken valve spring and it behaved just like your Tecumseh engine.

If the engine needs parts, I’ve heard that Tecumseh is out of business. Some small engine service shops may have some parts.

Connecting rods very rarely break such that they don’t rap VERY badly even if trying to pull start the engine with a rope. More often than not they punch a hole in the side of the block. The OP has mentioned no such rap.

It’s conceiveable that the OP can’t move the piston by pushing it down through the spark plug hole because the spark plug isn’t directly over the piston. He says it’s a flathead, the plug may be nearer the valves than the piston. He also mentions that the engine is easier to crank than it was earlier. If that means it’s easier to crank once he’s taken the plug out, it’s obviously because he’s got no compression with the plug out. He says the plug is wet, and that it fires once occasionally. Neither of these would happen with a broken connecting rod.

I have no doubt that this engine has it’s problems, possibly carburetor, ignition, valves or worn rings, but from the OP’s description I doubt that it has a broken rod.

The big warning I always got in regards to “too much starting fluid” was with diesel engines (as in heavy equipment). Perhaps it has to do with some really high chamber temps with a diesel and starting fluid, don’t know for sure. A buddy had a midsize Cattapillar that he used to plow his road and it always took about a half second spray before it would light off.

For $69,(sale) you can buy a 6.5 hp OHV 4-stroke replacement engine at Harbor Freight. Make it fit…

I always thought the big problem using ether on a diesel was if it had glow plugs. The glow plugs would ignite the ether and not necessarily when and where there should be combustion.

Wow. All of that blah blah blah. Its Junk

I think this “dozer” was pre-glow plug but in anycase the glow plugs are where you want stuff to burn and in vehicles/equipment with glow plugs they are controlled by a switch (be it a group of relays or not) that is they are not always on.