unleaded fuel on 76 mercruser 888

[russman]

is it ok to use unleaded fuel on a motor built for leaded. <br />should i be adding something? <br /><br />tried to find a old post on this but didd,nt see one.<br /><br />thanks<br /><br />russman

 

[Haut Medoc]

Re: unleaded fuel on 76 mercruser 888

It was posted somewhere. The answer is : Don't worry about it.

 

[Haut Medoc]

Re: unleaded fuel on 76 mercruser 888

Search under "leaded"...........J

 

[rodbolt]

Re: unleaded fuel on 76 mercruser 888

merc has a chart listing which engines need a lead additive and which dont. I no longer have a copy of it but it does exist. most folks I know running them dont sweat them. but the chart does exist

 

[Dunaruna]

Re: unleaded fuel on 76 mercruser 888

Wasn't all that long ago I was commenting on your 6000th post.<br /><br />Congrats on 7000 rodbolt!!!!!!!!<br /><br />Aldo

 

[ziggy]

Re: unleaded fuel on 76 mercruser 888

russman, i'm no mech, but i do have a old engine like yers. i run premium fuel. per the big note on my engine that says run premium leaded fuel. also i have a note in big letters from the engine rebuilder that took place in 98 for me, that says do not run unleaded fuel, use a lead additive. which i do. i thought the lead was to help cush the valves on the old engines. good luck and happy boating........

 

[Buttanic]

Re: unleaded fuel on 76 mercruser 888

Engines designed to use unleaded fuel have hardened valve seat to prevent valve seat resession which is caused by the lack of the lead film that forms on the valves and seats when using leaded fuel. This lead film acts as a heat transfer agent and a cushion to prevent an unharded seat from being beaten down into the head by the pounding of the valve closing. This is a slow process and generally boat engines do not see enough run time to make it a major issue.

 

[Scaaty]

Re: unleaded fuel on 76 mercruser 888

Originally posted by Buttanic:<br /> cushion to prevent an unharded seat fom being beaten down into the head my the pounding of the valve closing. This is a slow process and generally boat engines do not see enough run time to make it a major issue.

Agreed, by the time you would start to sink the valves in a boat engine (with the amount of actually run time), the boat will be in the Smithsonian if it last that long. (And that must be one OLD motor!)