Petrol additive for an old engine

[robgraham]

I've been given an elderly (40-50 years) cultivator - 4 stroke Briggs and Stratton single cylinder engine. Seems to be all OK and the engine runs fine. However I believe I should be adding something to the petrol to make it equivalent to that containing lead.

A local agricultural machinery company said this wasn't necessary, but a decoke would be advisable.

What's the collective's opinion please ?

Thanks

Rob

[Dave Plowman (News)]

It really depends what the exhaust valve seat consists of. If it's part of a cast iron block or cylinder head you might well have problems, but even then not always. If the material the seat is in is aluminium it will have a steel insert which is almost certainly hard enough.

[The Natural Philosopher]

I'm with the local company. A 50 year old briggs and stratton probably runs best on a mixture of poteen and medical ether anyway. :-)

Decoke and regrind the valves, pour in something vaguely petroleum based and it will run.

[robgraham]

Thanks guys - the thought had crossed my mind that the duty cycle,etc would be so low that an additive might well not be necessary.

Interestingly I have tried several what I thought were suitable outlets and they looked at me rather blankly !

Re. then suggestions of a decoke, how do I get round the probable problem of a gasket, etc ?

Thanks again

Rob

[adder1969]

Just adjust the valves, change the oil etc and use it. That's what I'd do if it were me and it otherwise ran ok.

[The Natural Philosopher]

Make one.

You can in extremis use lead sheet..copper sheet..I've even used cornflake packets for water gaskets.