3 replies to this topic

[primrose8]

Hi hope someone can help, daughters boyfriend just bought a 1987 mini 998 off e bay, old chap that had it, seemed knowledgable, had taken head off ground valves , fitted new hose and refitted engine painted but he had never tried to start it., asked him if he had static timed it and refitted dizzy leads etc , and he said he had.
Engine turned easy by hand, so got some petrol through to carb with plugs out , refitted and tried to start it, didn’t even try to fire .
So went back to basics, did valve clearances as he had them out , all very tight gapped so sorted them, static timed engine , timing marks lined up on pully, set at 6 deg btdc, no1 on firing stroke , no 4 valves rocking, set with light after recapping points which again were wrong.
Hey presto fired and ran.
But very rough, turned dizzy while running and got it better but still won’t pick up.
It ticks over but won’t rev if you give it a bit of throttle it dies , as if it’s choked up although choke is off, or fuel starvation? not sure if it might be carb related, not sure if he touched that, not had much to do with the carbs , but I’m sure it’s fuel related? Any ideas anyone many thanks!

[Quinlan minor]

If it has been standing for some years, particularly if it has had E5 fuel in it, I'd be draining the fuel tank, purging the lines, checking the fuel pump, stripping/cleaning the carburettor and putting fresh fuel in it as the first step.

[mab01uk]

BP - HOW PETROL CHANGES IN EQUIPMENT TANKS

"Loss of light components – impact on mixture The light components in petrol are lost first as the petrol sits in the fuel tanks. These components provide valuable octane benefits during cold start. Because they are volatile they compose most of the air fuel mixture during cold start, if they are absent then the mixture becomes lean resulting in higher temperatures, pre ignition, detonation and piston damage. This is generally the cause of piston damage in high revving engines used in boats and small engines such as chain saws etc. The portion of the petrol that remains has a higher density and higher octane but this is not available during cold start resulting in hard starting. Because the fuel carburetors and injectors operate on a volume metering system the higher density means that more fuel is introduced for a given volume of air and so the air fuel ratio is fuel rich. If all the fuel cannot be burnt then it forms carbon deposits that will foul the spark plug and cause the engine to stop and not start. This is generally the cause of problems in classic cars where the engine stumbles and hesitates or cuts out."

More:-

https://www.bp.com/c...hicle-tanks.pdf

Edited by mab01uk, 21 February 2020 - 09:49 AM.

[GraemeC]

Dashpot topped up?