Leaded or Unleaded Fuel?

[John Bett]

Hello. I have a '72 Evinrude 125 and have obtained the shop manual which says to use leaded fuel (underlined in manual to stress the point). I realize that was back before the ban, but would I be better off using lead additive? Also, is it ok to use octane boost in the fuel also for extra umph?

 

[CATransplant]

Re: Leaded or Unleaded Fuel?

Unleaded is fine in your older Evinrude, and 87 octane is also fine.

 

[DJ]

Re: Leaded or Unleaded Fuel?

Johnnn,<br /><br />Lead is NOT needed in an outboard. Lead was for valve lubrication in automotive engines. Your engine does not have valves.<br /><br />87 octane, with 50:1 mixure (one pint-TCW-3 to six gallons) will work just fine.<br /><br />I do not recommend "premium" fuels. They build carbon deposits and make "octane junkies" out of engines.

 

[itstippy]

Re: Leaded or Unleaded Fuel?

Higher octane will not give your motor extra umph. Higher octane simply raises the temperature at which the gasoline ignites; it does not have more explosive power. High-output, high compression motors need higher octane to prevent predetonation of the fuel because they run with higher internal temperature. Putting 92 octane gas in your outboard designed for 87 octane will screw up your timing and eventually ruin your motor. Don't do it.

 

[Walker]

Re: Leaded or Unleaded Fuel?

High octane gas will not hurt your motor unless it gets its octane boost from added alcohol, but it will hurt your pocket book.

 

[rwise]

Re: Leaded or Unleaded Fuel?

alcohol will wash the oil out of the bearings, don't do it!

 

[itstippy]

Re: Leaded or Unleaded Fuel?

Yes that's true most of the time, especially with something big like a 125. I should have said "can" ruin a motor, not "will". Sorry to be misleading and hope I didn't alarm folks.<br />A buddy borrowed my 4hp and when I got it back it ran crappy. Turns out he did me a favor and filled up the tank with premium before giving me the motor back. This affected the burn rate to the point that the little motor was working its heart out to push the boat when it couldn't get the fuel properly burnt. It sure didn't give it more "umph"! In time it could have caused severe damage to run like that. Fresh tank of 87 octane and he's back in fighting form.

 

[John Bett]

Re: Leaded or Unleaded Fuel?

Wow! Thank you all for the advice. I will use the standard 87 octane and unleaded (no octane boost). The reason that I asked was because the manual specified LEADED FUEL ONLY when there was the option of unleaded. I thought the added lead might have been good for something. Also, is penzoil 2 cycle outboard oil ok? I have heard bad things about it, but happen to have a case. Thanks!

 

[Dhadley]

Re: Leaded or Unleaded Fuel?

There was a time that the OMC engineers really were convinced that the motors had to be run on leaded fuel. They panicked when the lead was coming out. Thats what the rejetting and reduced timing and thick head gaskets was all about. Low and behold -- the motors ran just fine.<br /><br />Pennzoil TCW III is fine. We do a lot of testing for different things and the Pennzoil Blend has become our oil standard for carb'd 2 stroke outboards. And has been since the early 90's.

 

[DJ]

Re: Leaded or Unleaded Fuel?

Dhadley is right on-as usual.<br /><br />Lead did two things.<br /><br />1. It lubricated four stroke valves.<br /><br />2. It boosted octane.<br /><br />The petro industry has long since come up with suitable octane boosters in their formulas.<br /><br />Todays 87 is OK.

 

[Archangel2005]

Re: Leaded or Unleaded Fuel?

in 1977 wasn't the octane 87 alot different that the crap there selling us now?<br />wouldn't running 89 be just inside the safe zone?<br />i'm a new boater and read EVERYTHING you guys type.<br />also looking for specific carb advise on my 1977 johnson 115 outboard....

 

[Dhadley]

Re: Leaded or Unleaded Fuel?

The one time the government "got the lead out" an odd thing happened (imagine that). With the old leaded fuel the higher octanes burned cooler. With unleaded fuel the higher octanes actually burn hotter. Excess combustion temp is the #1 enemy of an outboard.<br /><br />Stick with fresh (6 week old fuel doesnt count as fresh) 87 octane, good oil, Champion plugs and set up for 5800 with an average load. Your motor will live a long and productive life.

 

[DJ]

Re: Leaded or Unleaded Fuel?

in 1977 wasn't the octane 87 alot different that the crap there selling us now?<br />

Not necessarily. Octane is octane. There are only two methods of determining it, and they both come to the same conclusions.<br /><br />Be aware that octane is only the fuels ability to retard detonation, however it is achieved, really doesn't matter.<br /><br />The fuels "today" are actually quite good compared to the crap we got in '77'.<br /><br />One thing you have to be aware of though, is that todays fuels do not like to "sit" for long periods. That is why I treat all my fuel with Sea Foam. Available at NAPA.<br /><br />If your engine is healthy, 87 is great.<br /><br />As far as the carbs. go, what secific info. are you seeking?<br /><br />I suggest you get a manual. You can get a specific "genuine" copy from Ken Cook. Or a general one here on iboats. See the lower left corner of the page.

 

[Dhadley]

Re: Leaded or Unleaded Fuel?

BTW -- the fuel can and most times does change every year. What we have today isnt the same as it was last year or 5 years ago or 10 years ect.....