Oops! Accidentally added mixed gas tank.

addysdady

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Jul 24, 2016
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I feel like such a bonehead. I picked up a project boat, 1999 Maxum 1800 XR, this evening. It has not run in a few years and the price was reflective of that. Worth the risk in my opinion. The gas tank was empty so when I got home I decided to fill it some. I must have been excited because I grabbed my 50:1 mixed tank and accidentally started to fill the boat. I put about 1 gallon or so in before realizing that it was the tank for my 2 stroke. I plan to siphon tomorrow morning. Is there anything else that I should do?

Thanks for your advice.
 

addysdady

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Jul 24, 2016
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Oops! Accidentally added mixed gas to 4 stroke tank

Hi all,

I accidentally grabbed the fuel for my 2 stroke and added it to my 4 stroke's tank. The tank was empty and I only added about a gallon or so before realizing my error. I will siphon the tank in the morning. Is there anything else I should do?

Thank you for your guidance.
 

Alumarine

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Feb 22, 2005
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I'm sure it will be fine other than smoking a bit.
Can't be worse than adding snake oil.
I think in the old days there was some oil product that went in the gas that was supposed to do something.

I would just dilute it with straight gas.
 

GA_Boater

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addysdady Merged both of your topics and moved to the proper section. :smile:

No harm - Run it and no need to empty the tamk.
 
Last edited:

jimmbo

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May 24, 2004
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Won't do it any harm what so ever. You put 1 gal of fuel that was 2% oil. If you have a 30 gal tank , filled, you now have less than 0.0067% oil
 

8v-of-fury

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Not only that, we winterize our outboards on a 25:1 tank.. 2 stroke or not, they get it. The I/O's get a HEFTY dose of fogging oil too, unless EFI.

If anything, I'd actually run it on a 50:1 for the first bit.. lol Lubrication has never killed an engine, truth.
 

EchoNovember

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Just finish filling it with plain gas and count it as upper cylinder lubricant. The worst you'll get is some extra smoke. Now, if you ran straight 50:1 you could end up with fouled plugs.
 

jimmbo

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Not only that, we winterize our outboards on a 25:1 tank.. 2 stroke or not, they get it. The I/O's get a HEFTY dose of fogging oil too, unless EFI.

If anything, I'd actually run it on a 50:1 for the first bit.. lol Lubrication has never killed an engine, truth.

OMC found they had far fewer warranty claims for preignition damage after they reduced the ratio from 24:1 to 50:1. Less carbon build up on the piston crown and head. Granted that was before the TCW oils were in wide use. If bearings roll smoothly using 50:1 they aren't going to roll any smoother with 24:1.
But people can run whatever they want, it is their engine
 

bigdee

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Good move! No really it is since engine has not been run in awhile...it will supply much needed upper cylinder lubrication and help clean fuel injectors. I would not dilute it.
 

tpenfield

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I run 2-cycle mix in my 4-cycle engines all the time . . . for things that I don;t run that often, as it continually lubricates the intake and combustion chamber, etc. As a matter of fact, the way to fog an MPI engine for layup is to run a 10:1 mix of gas/2-cycle oil.
 

ctrobk

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The SELOC Mercruiser book actually recommends using mixed fuel to winterize, it was news to me when I read it. Like the other posts say, maybe just some extra smoke.
 

jimmbo

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The SELOC Mercruiser book actually recommends using mixed fuel to winterize, it was news to me when I read it. Like the other posts say, maybe just some extra smoke.

It could be considered Mosquito Control
 

tpenfield

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FWIW - I find that the 50:1 2-cycle mix does not really smoke much, if any. Probably has something to do with the full exhaust stroke of the 4-cycle.
 

bigdee

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The SELOC Mercruiser book actually recommends using mixed fuel to winterize, it was news to me when I read it. Like the other posts say, maybe just some extra smoke.

Towards the end of summer I run my mowers on my leftover 50:1 mix and leave it in the tank until spring....just as good as stabilizer. I also run my standby generator on 50:1 before storing it. No smoke after warm-up.
 

EchoNovember

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After reading this thread, I think I know what to do with my old 50:1 mix. I used the cheap oil the PO gave me and every time I try to start it (keyword try) and then pull the plugs to check them, they are covered in oil but not gas. The gas evaporates or partially burns off, leaving the oil behind. If I do get it running and pull the plugs afterwards, same thing: oil covered plugs. I am going to try running that crap gas through the lawnmower to use it up and switch to a higher quality TC-W3 Pennzoil.
 

MRS

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It could be considered Mosquito Control
He,he,he I like it. Once was cutting wood all day tired thought I had enough gas in truck to make it home not! So dump in 3 gallons of pre mix got home truck loved it.
 

bigdee

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He,he,he I like it. Once was cutting wood all day tired thought I had enough gas in truck to make it home not! So dump in 3 gallons of pre mix got home truck loved it.


Funny same thing happened to me while picking up a load of cut firewood. All I had was a 5 gallon jug of #1 kerosene so I poured 1/2 of it the tank and drove about 30 minutes to get home....truck ran fine! I filled the tank with gas from my farm gas pump before turning engine off and drove back to get more wood.
 

Chigwalla

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Old thread I know, but I thought I'd chuck this in for anyone who's interested...
The Merc factory 'recipe' for the brine used to winterize MEFI engines calls for 2l of TCW3 mixed into 18l of fuel.
FWIW, they also call for fuel stabilizer.
 
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