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View Full Version : Bonehead mistake: 2 Cycle fuel in 4 Cycle tank


kppurn
06-07-2005, 09:10 PM
Yes, I'm an idiot. I wasn't thinking when I got back to the shop tonight and started filling the mowers for tomorrow. I started filling the Lazer when I realized I grabbed the two cycle can on accident. The five and half gallon tank is now full with about 1-1.5 gallons of two cycle and the rest straight.

My question is, what the heck do I do now?

dvmcmrhp52
06-07-2005, 09:19 PM
Just run it, it won't hurt running 2 cycle in a four cycle for a short period, it will only foul plugs and with the amount you're talking it won't even do that.

Restrorob
06-07-2005, 09:48 PM
I agree with dvmcmrhp52 Wont hurt a thing !

dutch1
06-07-2005, 10:44 PM
One tank of this mixture will not hurt anything in my opinion. It would not hurt to add straight gas when you get the tank down a bit. Continued use will become a problem. I am aware of a lawn/landscape company that made a decision to run 2 cycle fuel in everything due to the screw ups of undocumented alien help. It happened to be leaf season and they brought in two large Billy Goat leaf vacuums with 18 hp Briggs Vanguards. They had used used 2 cycle fuel long enough to freeze the valves on both banks on both engines.

fixer67
06-08-2005, 01:37 AM
Just run it, it won't hurt running 2 cycle in a four cycle for a short period, it will only foul plugs and with the amount you're talking it won't even do that.

I agree. No damage done. Just run it out and when the tank gets down cut it with more straight gas. You may notice a little smoke until it is all gone. After it is gone check the plugs to see if they need changing but most likely they will be OK. I have seen engines that burn more oil than gas due to bad rings and only fouling plugs was a problem. Relax you have nothing to worry about

Oldtimer
06-08-2005, 08:10 AM
You can run 2 cycle mix in your 4 cycle engines all the time if you want to. I have been in selling equipment for 20 years and have never allowed straight gas in my store. We usually buy about 100 to 125 gallons at a time and the mix oil is in the drums and containers before we go to the gas station. The only thing going out of our store or shop that doesn't have 50:1 in the tank is a diesel. This goes for all equipment we sell and service.

This year I will sell around 1500 pieces of gas powered equipment, both 2 cycle and 4 cycle, and they will all have Amoco 89 (BP) octane mixed with Shindaiwa 50:1 oil. For about 12 years we used Opti 2 mixed at 100:1 in everything and the move to Shindaiwa 50:1 happened when we received a 55 gallon drum as a perk for large orders. My experience tells me that a high quality oil and a high quality fuel mixed according to the oil supplier's recommendations will work in just about any modern engine except for Tecumseh's 24 & 32:1 engines.

Oldtimer
Just growing older in Pensacola, Florida

kppurn
06-08-2005, 09:23 PM
Thanks for all the replies. I ran it today with no problems. The plugs are fine as well.

Thanks again

CincyWolf
06-08-2005, 11:56 PM
Like the others say, that small amount won't hurt anything. If you have 1.5 gallons of a premium 50:1 mix out of 5.5 gallons total you are not likely to know the difference.

As a former dirt bike racer and tuner I will say that if you convert a straight gas engine to a pre-mix you need to pay attention to your carburetor jetting to make sure you don't lean out which could cause an overheating problem. On highly tuned 2 stroke engines even a small change in pre-mix strength will necessitate a change up or down in the main jet size - assuming if it was tuned just right before making the change. I found that most people didn't realize this and it made a difference between winning, losing and the ever dreaded DNF. I'm not saying that mower engines are the same as a high output motocross engine but the same principles apply.