Oh Boy! Got myself in a bind with new Honda

robertjp

Petty Officer 2nd Class
Joined
Dec 19, 2002
Messages
112
So yesterday I bought a new Honda 50 HP (gave a deposit) and it never dawned on me that my built in gas tank in my 16 Sylvan (18 gallon Mueller) has a 50:1 oil mix in there. The Honda is 4 stroke and doesnt mix oil with gas. Now I realize I can syphon the gas out but wont the oil residue left in the tank mess up the new 4 stroke or will it be diluted so much it wont matter? I am really nervous about this as I think replacing the tank would be a giant hassle. What should I do? Thanks Bob
 

Sea Rider

Supreme Mariner
Joined
Sep 20, 2008
Messages
12,345
Siphon the most mixed fuel on tank, top tank with fresh fuel and go boating....

Happy Boating
 

Groo

Seaman
Joined
Jul 31, 2017
Messages
52
If you drain 50:1 down to 9%, then top off, you are going to be like 500:1

remember, 2 stroke oil is intended to burn. I wouldn't worry, and didn't work myself when I recently went from premix to 4 stroke and reused my cans.
 

gm280

Supreme Mariner
Joined
Jun 26, 2011
Messages
14,585
its got about 15 gallons of 18 left. Thanks

If I calculated it correctly (yeah right) and you have the typical 50:1 in the tank now and you have 15 gallons left, you now have 60:1 mixture in there if you top the tank off with gas JMHO
 

GA_Boater

Honorary Moderator Emeritus
Joined
May 24, 2011
Messages
49,038
Consider it break-in oil. Ask your dealer to be sure.

This probably happens more than you think with re-powers from two to four strokes.
 

matt167

Captain
Joined
Sep 27, 2012
Messages
3,630
I'd ask the dealer but really, they have to deal with that type of thing all the time. personally, drop it down to a very low ratio and call it top end lube/ break in lube
 

GA_Boater

Honorary Moderator Emeritus
Joined
May 24, 2011
Messages
49,038
If the old motor is still on the boat, you could go out for a 15 gallon cruise to reduce the amount of pre-mix.

Just don't run out, make it a 14.5 gallon cruise.
 

harringtondav

Commander
Joined
May 26, 2018
Messages
2,438
Ditto all above. You'll get a little smoke, maybe need to clean up your spark plugs, but I doubt it. Keep topping off your tank, and run the Honda like you mean it. No excessive babying. I had some premix I needed to dispose. I poured it into my snaggletooth '99 Durango. No problem, except for those following me.
 

BillP

Captain
Joined
Aug 10, 2002
Messages
3,290
I had the same issue and ran about 20 gals of 50:1 in my new 50 4 stroke. Had the engine for yrs and it never posed a problem...except it took a long time to drain the tank @ 2 gph.
 
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