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Unleaded or leaded mix

W

waldoh

New member
Hi
i just brought a mercury

Hi
i just brought a mercury mariner 10hp which from what i can tell is a 91 model going by the serial number OD052752
what i would like to know is do the mercury outboards from this yr take an unleaded or leaded fuel mix and where is a good place online to purchase a reliable manual for this motor
 
it hasn't been decades in

it hasn't been decades in Australia maybe it has been where you are from but not Australia
if the motor was built for leaded u need to add a fuel additive or you can kill it
the motor is almost 20yrs old if i have traced the serial correctly and Australia still had leaded petrol back then so i need to know what fuel i need so i don't kill the motor
 
"Too true! I recall what lead

"Too true! I recall what lead deposits did to spark plugs when I was a kid, but I believe lead deposits wouldn't be a problem with the gap less plugs.

Opinions?

Jeff"
 
"well, lead was used in gas to

"well, lead was used in gas to provide upper cyl. lubrication mainly to protect the valves and to help lube the entire upper cyl. area. When lead was removed from fuel, the valves started receding into the seats from wear due to lack of lubrication. So finnally, when your engine ran so bad it was time to overhaul it, hardened steel valve seats could be installed and your good to go with unleaded fuel without further problems. This would be an issue in 4 stroke outboards or any older 4 stroke engine. Not so in a two stoke. since the lubrication comes from the oil you add to the fuel and the fact that there are no moving parts other then the piston in the upper cyl area. So dont add lead to your fuel on any 2 stoke engine. Its a waste of your money and the lead build up can damage your engine. Of course there is alot more to this, but for this conversation I hope it will do."
 
Excellent ty for the replies i

Excellent ty for the replies it is very much appreciated and has helped a lot as i am not very mechanically minded
Keep up the good work this site is brilliant

P.S.
are the mariner 10 outboards a reliable motor? i cant seem to find any info on them on the net
 
"I won't say how I know th

"I won't say how I know this but 100LL works just fine in my old 83 merc, I haven't ever fouled a plug in many years. It has no performance value unless you change the timing for the burn/octane. It does however last all winter long without additives."
 
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