Will a four-stroke lawn mower with no oil in it hold up long enough to mow my lawn once before I throw it out?

Question

This mower burns oil, and I think the rings are shot. I'm going to get around to getting another junk mower, but for the time being, do you think I can get by with mowing just once with no oil in the crankcase? It's a pain right now because I have to constantly clean the plug... perhaps 15 times in a single session of mowing the lawn. Do you have any ideas for a flammable lubricant I can put in there that will burn cleanly enough to not foul the plug? (I considered using 2-stroke oil or even gasoline in the crankcase.) Keep in mind that I'm not interested in any spectacular longevity... just to get me through until I can replace it.

Thinking about this... I think it'd be pretty fun to watch it seize up. Comment on how safe you think this would be.

Answer 1

Give it a try. But first organise a raffle, sell tickets on the time the mower runs before seizing up......sell LOTS of tickets .......give half the money to the winner....... use the rest of the money to buy a new mower.
If you fill the crankcase with diesel it might give you a few more minutes of mowing time as it doesn't sound as if there is enough compression to ignite the diesel fuel......... on the other hand it might catch on fire......... in any case just remember to sell LOTS of tickets !

Answer 2

DO NOT USE GAS IN THE CRANKCASE! You could cause an explosion and risk serious injury or even DEATH!
It's a crap shoot - anyway you look at it!
Are you sure the gas you are using is clean? You may want to try a hotter burning plug that might burn away some of the oil.
The piston rings being 'shot' is not the only reason you would have to clean the plug as often as you state. A four-stroke engine has an intake valve and an exhaust valve, both of which have valve guides which can fail and cause the same
condition(s) as 'shot' rings. Whatever the cause, if you must clean the plug (15) times during a mowing cycle, the engine should be repaired or scrapped! It highly likely that a small, single piston four-cycle engine, which by the way uses a splash oil system rather than an oil pump, will most definitely fail or seize-up soon after start-up if run with no oil in the crankcase.
An engine seizing-up is not a spectacular sight - as the engine heats up it begins to run a little better just before it stops as the piston binds to the cylinder wall, which can be dangerous if and when the engine throws the connecting rod and the rod comes through the wall of the crankcase. If the engine gets hot enough there is always the danger of fire, as well.
Buying a 'new' junk mower may seem a money-saving move, but if you but an inexpensive NEW mower AND maintain it with regular oil changes your long term costs will be much lower than replacing your 'junk' mowers as frequently as I suspect you probably do. Be careful!!!!!!

Answer 3

First, unless you have a very small yard, it is unlikely that your mower will last longer than just a very few minutes without oil. A couple of tips that may help you stretch a few more mowings from your dilapidated mower. First, drain the oil (what little there is) and replace it with SAE 30, a thicker oil which be less likely to leak past your piston rings. Second, replace your spark plug with a "hotter" plug. If you are running say a Murray Mower with a Briggs & Stratton engine and using a Champion RJ19LM plug, the 19 is the heat range. Move up to a 20 or 21 which is a "hotter" plug and will resist oil fouling.

Answer 4

Let me tell you, it is certainly fun seeing a worn out engine grenade, after draining the oil and running it..... by grenade.... I mean it never seized up, rod broke at the wrist pin (connects the connecting rod, to the piston) and proceeded to go through the block, spewing chunks of aluminum everywhere......
Takes no more then 5 minutes.... give or take a couple minutes for it to do either of the two.... seize or blow up.



It may seize, or it could turn into a grenade..... not something you want to gamble with...



To get some more use out of it..... I'd suggest getting a quart of 20w-50..... (only should take 20 ounces of this for a push mower) to calm the consumption down.... if its still bad, mix 10 ounces of 20w-50, and some cheap oil treatment (doesn't matter..... can be stp to valvoline) just anything to calm the consumption down....

gas/oil mix in a 4 cycles crankcase..... will result in less then pretty results (you remember the grenade part of this post right?.....ok)


I've seen poor schmucks use 2 cycle engine spark plugs in 4 cycle engines..... and these plugs can certainly deal with oil consumption....




As a side note.... when it does get replaced, and still runs, go out in a wide open field, drain the oil.... rip the governor off, start it and run like hell to a far away distance and see what it does if you want.... I just wouldn't be near it when it blows up.

Answer 5

90% chance your air filter is plugged causing the breather tube to draw too much vacuum from the crank case.

Without oil, it will seize up in about two minutes. Then the connecting rod will break and be forced thru the engine housing.

Remove your air filter, add half a quart of oil, and run it again.
I'd say it would last a long time and not burn oil anymore.

Answer 6

I would NOT recommend it.
A lawn mower engine turns at about 3600RPM.
It might just seize, and then again it might throw the rod through the block and scatter hot metal over a fairly wide area. (I've seen a thrown rod throw parts of the block as much as 100' !!)

You COULD try a spark plug about 2 ranges hotter to help burn the oil, but that could also melt a hole in the piston, or open up the spark gap a bit, or both.

Answer 7

Sounds as if its really shot, the 2 stroke oil sounds like a good idea. I wonder if some heavy straight weight oil like 50w would stay in there any better

Answer 8

I'm so exhausted from listening to your situation that i had to wait til i had enough energy to answer why don't you just pay the neighborhood kid to do it and enjoy the moment

Answer 9

I would try one of those superlubricants, you know, where the engine keeps running after they drain it out, it bonds to the metal.

Answer 10

It depends on how big your yard is. It might last without oil.