50-1 Mix in a new 4 stroke

Sam2001

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Sep 14, 2017
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41
I just upgraded to a new Tohatsu mfs 60 and still had several gallons of some pre mix 50-1 gas in the integrated tank on my boat. The dealer is telling me not a problem to leave it in there and run it through and switch over to straight gas . This is a brand new motor that needs to be broken in. Would there be any problems on running that pre mix gas through a 4 stroke ?
 

GA_Boater

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Better give the motor back to the dealer - You don't trust him.
 

ahicks

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Better give the motor back to the dealer - You don't trust him.
May not sound like a great idea at first, but I think you'll find it won't hurt a thing. So I would have to agree with the dealer. It may not break in as quickly, but it will break in. As far as being smokey, nope! Not even a light haze. As far as any other issues running 50:1, nope!

50:1 actually makes awesome fuel stabilizer for 4 strokes. I use it frequently on engines that are going to be sitting around for a while (including my lawn equipment and pressure sprayers). There's nothing else that will stabilize the fuel while giving the valves, rings and cylinder bore a nice thin protective layer of high quality oil.

Not my trick. It was passed on by a a Florida outboard tech that's been working on boats forever (one of the very few I trust). He said he started using it on inboards and I/O's, but when the 4 stroke outboards came out, he started using it on those as well....

The ONLY caution I would be aware of is an engine with an oxygen sensor. They may not like that oil at all. I don't know that for a fact, but would hate to recommend it and have it cost somebody a sensor.... -Al
 
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matt167

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Sep 27, 2012
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3,630
2 stroke oil is for the most part, upper cylinder lubricant when used in a 4 stroke.. Not going to do a thing
 

poconojoe

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This is very interesting.
When I read the OP's question, I thought "what"! No way!
Well, you learn something new every day, as they say!
 

Sam2001

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Sep 14, 2017
Messages
41
Thanks for your all's input , it's just one of those things i never heard of before. My thoughts were if anything were to happen it might clog up the fuel injector or foul out a plug . This is the first 4 stroke motor I've had so I'll be going through a learning curve with this.
 

Sea Rider

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Sep 20, 2008
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12,345
How many pre mixed gallons are still sitting in the tank ? Add the same amount of pure gasoline to lower the ratio to 100:1, will smoke much less.....

Happy Boating
 

ahicks

Captain
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Sep 16, 2013
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I deleted my original message relating to common sense.....
Sorry for wasting the band width.
 

Sam2001

Seaman Apprentice
Joined
Sep 14, 2017
Messages
41
How many pre mixed gallons are still sitting in the tank ? Add the same amount of pure gasoline to lower the ratio to 100:1, will smoke much less.....

Happy Boating

Its a 15 gallon tank and I have 10 gallons of pre mix in there. I'll try and fit as much straight gas in there as i can. Thanks!
 

Sam2001

Seaman Apprentice
Joined
Sep 14, 2017
Messages
41
May not sound like a great idea at first, but I think you'll find it won't hurt a thing. So I would have to agree with the dealer. It may not break in as quickly, but it will break in. As far as being smokey, nope! Not even a light haze. As far as any other issues running 50:1, nope!

50:1 actually makes awesome fuel stabilizer for 4 strokes. I use it frequently on engines that are going to be sitting around for a while (including my lawn equipment and pressure sprayers). There's nothing else that will stabilize the fuel while giving the valves, rings and cylinder bore a nice thin protective layer of high quality oil.

Not my trick. It was passed on by a a Florida outboard tech that's been working on boats forever (one of the very few I trust). He said he started using it on inboards and I/O's, but when the 4 stroke outboards came out, he started using it on those as well....

The ONLY caution I would be aware of is an engine with an oxygen sensor. They may not like that oil at all. I don't know that for a fact, but would hate to recommend it and have it cost somebody a sensor.... -Al
Right ON ! i took the motor out and ran it for 2 hours , no issues , no smoke , ran like a dream. Thanks for the sound advice!!
 

paulswagelock

Petty Officer 3rd Class
Joined
Jan 10, 2018
Messages
99
I run 2 stroke in my 4 stroke lawn equipment, golf carts, tractor, etc. as an upper cylinder lubricant. Usually closer to 100:1 but I never measure that close. Won’t hurt, as motor gets older likely helps.
 

MattFL

Master Chief Petty Officer
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Oct 20, 2010
Messages
827
It will be fine. I couldn't tell you how much premix I ran through my old truck to get rid of it (new truck is diesel). Also my lawn mower gets more premix than strait gas. Every time we ride the dirt bikes they get fresh gas, at the end of the day there is often some left over so it goes through the lawn mower to get rid of it. It's mixed 32:1 and aside from the smell of burning 2-stroke oil, there's no noticeable difference in how it runs.
 
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