1
$\begingroup$

So I was thinking that its not good to let a car engine sit. Since the oil and all moves down to the pan and all that other fun stuff, so what about small engines? I was thinking about whether it was good to start, for example, my 3 small engines. Being the push mower (4-cycle), riding lawnmower (4-cycle), and weed wacker/trimmer/eater (2-cycle). It seems to me to be a good idea since the oil and stuff must, like a car, sit someplace. And for 2 cycle all that lubrication would eventually dry up, and that would seize the engine, right? Now I am going to add that there is no fuel left in these engines. Well the rider does have a half tank.

So simplifying, is it a good idea to start these smaller engines like once or twice a month? Just to keep everything lubricated. Also adding, if this is benifitial, which one (4-cycle/2-cycle) would get the most benefit? Thank you

Side note: I hope this is fine for this site, but there is no place else to ask (that I know of).

$\endgroup$
2
  • $\begingroup$ It's fairly common to winterize these engines and not start them for several months. (Mower, outboard anyway) If properly handled, it doesn't seem to do them harm. $\endgroup$ Feb 28, 2017 at 12:28
  • $\begingroup$ All men know that idle machinery rusts... $\endgroup$
    – Paul Uszak
    Apr 13, 2017 at 23:07

3 Answers 3

2
$\begingroup$

Gas tanks are not completely sealed. As gas goes to your engine, air must enter the tank to equalize the pressure. This vent is typically located in the gas cap. As the this tank sits, it gets hot and cold with daily temperature swings. Every hot cold cycle, it pulls a little moisture in and condenses. This results in water accumulation in the tank that causes rust and can prevent startup. Modern 10% ethanol gasoline will absorb some amount of water and will go through your system as normal. This is why people recommend running engines every once in a while. Burning this gas is one method of removing that moisture. Realistically though, you are probably not going to go run a tank of gas through your weedeater/lawn mower once a month in the middle of winter.

I recommend filling the tank full of gas for storage and adding fuel stabilizer. I don't know all the chemistry of fuel stabilizers, but here are some links:
Wiki Fuel Stabilizer Section
Brigs & Stratton Fuel Stabilizer Article
Fuel and Friction Article

Remember, an empty tank can collect moisture in the same way. Removing all the gas may remove the stale gas related issues, but with a larger empty volume, it will actually make the water and rust problem worse.

$\endgroup$
1
  • $\begingroup$ I like this answer. I pretty much get what the two of you (who answered at this point) are saying. Thank you for the links. Also, Never really planed on running a full tank. But thinking more of just letting the thing 'idle' for a good 10 min or something. $\endgroup$
    – Ljk2000
    Mar 4, 2017 at 2:12
0
$\begingroup$

Gasoline has a relatively short "shelf life" before sufficient volatiles have evaporated, leaving a highly flammable but not particularly aerosolizable remainder. That's why owner's manuals (the first thing you should have read before posting) recommend running the engine until the tank is dry before storing.
Lubricating oils have a much lower evaporation rate, and can pretty much sit around forever without loss of functionality. The reason to change the oil is to remove "sludge," which is a mixture of foreign particles and partially oxidised oil.

Stern Reprimand

Just because there's no automotive.stackexchange site hardly means there's "No place to ask" on the net. There's approximately googol-7 websites dedicated to ICE design and maintenance.

$\endgroup$
3
  • 1
    $\begingroup$ Are you sure? mechanics.stackexchange.com $\endgroup$
    – hazzey
    Feb 28, 2017 at 15:43
  • $\begingroup$ @hazzey that's a good catch $\endgroup$ Feb 28, 2017 at 16:50
  • $\begingroup$ I would have read the owners manual, but I have none since this stuff was given to me. So I did not know the part on running it dry. But I do remove the gas with a gas pump. $\endgroup$
    – Ljk2000
    Feb 28, 2017 at 20:11
0
$\begingroup$
  1. A chain saw repair person said that chain saws have a carb which needs to be used or it will become unusable. He said a chain saw needs to be run at least twice per year. It's a "diaphragm" carb -- which can operate in any position because it has no float. He said a homeowner should have an electric chain saw rather than a 2-cycle.

  2. I can't personally attest to the effectiveness of this but an engineer I used to work would prepare his four cycle engines for winter storage by running them with Coleman fuel, AKA white gas, until they went dry. His explanation was that the naphtha based fuel left very little reside. As would be expected the engines ran particularly badly with the goofy fuel but once they ran out, what was left would evaporate cleanly. I have never tried this and would not recommend it unless you are prepared to take the engine apart to recover from the experiment. Observe, I said four cycle. If you try this with two cycle equipment, say goodbye first.

$\endgroup$
2
  • $\begingroup$ Just started my Stiehl chain saw after it sat for 3 or 4 years. It took about 4 or 5 pulls. Also Honda portable electric generator after about a year, 2 pulls. It depends on the equipment engineering . $\endgroup$ Sep 27, 2017 at 1:11
  • $\begingroup$ Wow. My experience with the repair guys is they have seen every combination of problems ... on the equipment they work on. I will guess the guy I quoted had not worked on Stiehl. It is also possible he sees a biased sample, chain saws that have trouble. If you have good equipment, use stabilized gas and keep things maintained the repair guy will never see your equipment. Your Honda generator has a diaphragm carb? I would have thought it would have a float but I have never had one apart. My friend had one of those, VERY nice. Good choice. $\endgroup$ Sep 27, 2017 at 2:50

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.