1992 Yamaha 40hp. Fuel ratio

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Douglasdzaster

Member

• Sep 7, 2020

• #1

I just purchased a 1992 Yamaha 40MSHQ. I’ve done some work on it and now ready to start it but I’m getting mixed information on fuel ratios for Yamaha. Is it 50:1 like other outboards or 100:1 which is what I’m reading on line? Such a big difference I want to make sure I get it correct.

 

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racerone

Gold Medal Contributor

• Sep 7, 2020

• #2

It shows that it has automatic oil injection on the parts list.

 

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Douglasdzaster

Member

• Sep 7, 2020

• #3

racerone said:

It shows that it has automatic oil injection on the parts list.

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Yes sir. It’s now on a flat bottom hooked up to a portable tank.

 

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racerone

Gold Medal Contributor

• Sep 7, 2020

• #4

So are you going to run with the automatic oiler in service ?---Or are you bypassing this system and mixing gas / oil yourself ????

 

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Douglasdzaster

Member

• Sep 7, 2020

• #5

I don’t know how it was set up when new but there’s no pump. Hooked straight to a portable tank with an in-line fuel filter. Yes I’ll be mixing fuel myself.

 

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Douglasdzaster

Member

• Sep 7, 2020

• #6

Sorry I didn’t see your reply. It’s been bypassed and removed. I’ve redone a few other things on it that was someone’s patch work. Finally ready for fuel and be started.

 

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racerone

Gold Medal Contributor

• Sep 7, 2020

• #7

run with 50:1 mix.

 

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Douglasdzaster

Member

• Sep 7, 2020

• #8

racerone said:

run with 50:1 mix.

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Thank you for your input. I really appreciate it.

 

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Douglasdzaster

Member

• Sep 7, 2020

• #9

Should I stay with 87 octane or is there an advantage to higher octane.