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#1
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Leaded or Un-Leaded?
excerpt from: http://www.radford.edu/~wkovarik/lead/overview.html
"When you fill your car up at the gas pump, you may notice that you are using "unleaded" gasoline. Lead is not something that comes with gasoline that has to be taken out -- it was deliberately added by the oil industry to boost "octane" or anti-knock ratings for fuel. It had to be phased out by government order, for public health reasons, starting in 1975, and concluding in 1986. It was also banned in various European nations in the 1990s. It is still having serious public health impacts in developing nations, and a complete global phase-out has long been advocated by the World Health Organization and all other international health organizations." excerpt from: http://www.chevron.com/prodserv/fuel...etin/unld-gas/ Marine Engines: There is concern about older four-stroke cycle engines in marine service, which were designed prior to the introduction of unleaded gasoline (pre-1974). Under severe duty, these older engines could have valve recession problems. If these engines are in severe duty service, owners should consider installing hard seat inserts or using lead substitute additives to minimize valve recession. Products like this have been found effective in minimizing valve recession. Mercury, who is a major supplier of Stern Drive Engines for marine use, advises that their engines are automotive based and have hardened exhaust valve seats. Most of Mercury's outboard engines were developed with unleaded gasolines, and Mercury's only concern is with octane number. All of Outboard Marine Corporation's current four-stroke cycle engines were designed for unleaded gasoline and valve protection additives are not needed. Additives are also not needed for their two-stroke cycle engines, however, some of them may have the need for octanes higher than 87(R+M)/2. The newer Volvo Pinta Stern-Drive four-stroke cycle engines are designed for use with unleaded gasoline. Some of the older engines are not. We would suggest owners contact their dealer for advice if they have an older engine in severe service. Yamaha outboard engines operate satisfactorily on unleaded gasoline. At least one model, a high performance Model 225, requires a minimum 89(R+M)/2 gasoline. Outboard Marine Corporation has issued a Service Letter for General Information #53, August 1985, subject: Gasoline Lead and Alcohol. This bulletin is very comprehensive on their position regarding unleaded gasoline use and has extensive guidelines relating to their minimum octane level desired. This should be available from Johnson and Evinrude dealers. |
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#2
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Leaded or Un-Leaded?
In article ,
"Stanley Barthfarkle" wrote: If these engines are in severe duty service, owners should consider installing hard seat inserts or using lead substitute additives to minimize valve recession. Mine doesn't see sever duty unless going all out across a big lake is severe duty. I used lead additive in the tank for my first fill up (I just bought it) due to the label. Was Iwrong in doing so? Do I not need to add lead? I have no idea what sort of valve inserts this engine has. -- It's no good unless it makes your eyes water. |
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#3
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Leaded or Un-Leaded?
As stated before - use mid grade gas and you will be fine. On 2 stroke
engines you have no valves to worry about. However, you do have preignition issues to worry about. The lead helped w/ this. When leaded fuel went away - outboard manufacturers recommended you use at least 90 octane fuel in the older engines or change the head gaskets to a thicker gasket to reduce compression to prevent preignition. Some will say use the cheap stuff but no more than you burn in a boat - the 10 cents a gallon is cheap insurance in my opinion. -- Tony my boats at http://t.thomas.home.mchsi.com "Jeepers" wrote in message ... In article , "Stanley Barthfarkle" wrote: If these engines are in severe duty service, owners should consider installing hard seat inserts or using lead substitute additives to minimize valve recession. Mine doesn't see sever duty unless going all out across a big lake is severe duty. I used lead additive in the tank for my first fill up (I just bought it) due to the label. Was Iwrong in doing so? Do I not need to add lead? I have no idea what sort of valve inserts this engine has. -- It's no good unless it makes your eyes water. |
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#4
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Leaded or Un-Leaded?
In article 0O1Jc.50496$WX.15047@attbi_s51,
"Tony Thomas" wrote: As stated before - use mid grade gas and you will be fine. On 2 stroke engines you have no valves to worry about. However, you do have preignition issues to worry about. The lead helped w/ this. When leaded fuel went away - outboard manufacturers recommended you use at least 90 octane fuel in the older engines or change the head gaskets to a thicker gasket to reduce compression to prevent preignition. Some will say use the cheap stuff but no more than you burn in a boat - the 10 cents a gallon is cheap insurance in my opinion. Cool, will do. -- It's no good unless it makes your eyes water. |
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#5
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Leaded or Un-Leaded?
In article , Jeepers
writes: I thought Leaded fuel went out in the mid 70s. Why then do I need Leaded fuel on a 1985 motor? I don't know if this applies, but I have a 1985 Merc in-line 6. I don't know if this is a mechanic's urban legend of what, but here goes: Shortly after we got the boat in 1995, one of the pistons came up pitted. $700.00 later, the mechanic told me that the pitting was from the use of unleaded regular (87 octane) fuel and that the motor had been designed to use regular leaded fuel (which was still available, he said, for marine use at that time). He recommended using premium fuel to avoid future problems. As of the last tune up, last year, everything was still okay. Frank Bell ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ A. Top Posting. Q. What's the most annoying thing on Usenet? |
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#6
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Leaded or Un-Leaded?
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#7
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Leaded or Un-Leaded?
Old Wives Tale. The only difference in an engine designed for leaded vs.
unleaded fuel is the way the bottom of the valve guide is cut. For leaded, they cut a square shoulder into the bottom so the lead that collects on the stem gets scraped off and rolled up into a donut to lubricate the valve. For unleaded its cut with a taper to prevent gauling the valve. The pitting is caused by detonation which can be controlled either by retarding the timing a bit or using a higher octane fuel. "FRANKWBELL" wrote in message ... In article , Jeepers writes: I thought Leaded fuel went out in the mid 70s. Why then do I need Leaded fuel on a 1985 motor? I don't know if this applies, but I have a 1985 Merc in-line 6. I don't know if this is a mechanic's urban legend of what, but here goes: Shortly after we got the boat in 1995, one of the pistons came up pitted. $700.00 later, the mechanic told me that the pitting was from the use of unleaded regular (87 octane) fuel and that the motor had been designed to use regular leaded fuel (which was still available, he said, for marine use at that time). He recommended using premium fuel to avoid future problems. As of the last tune up, last year, everything was still okay. Frank Bell ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ A. Top Posting. Q. What's the most annoying thing on Usenet? |
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#8
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Leaded or Un-Leaded?
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#9
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Leaded or Un-Leaded?
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#10
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Leaded or Un-Leaded?
Jeepers wrote in message ...
In article , (Matt Lang) wrote: He is probably right about useing premium or at least mid grade but for your 2 stroke its not about lead its about octane... I had a 68 Merc I6 and it ran great on mid grade. Also make sure not to use fuel with alcohol or octane boost. Matt Thanks! The boat is at the doctor right now. Intermittent rough running, I think I have a bad coil or bad fuel line, something. Plus it needs a new prop and a tune. Mine run bad for a while .. it was leaking fuel lines after the fuel pump... also the fuel pumps were old and weak ... |
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