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Thread: Car running poorly

Discuss the Austin Healey Sprite and the MG Midget. Two different but similar cars sometimes referred to collectively as the Spridget.

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    Jedi Knight bugedd's Avatar
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    Car running poorly

    Hey guys,

    I have neglected the car a bit and let it sit a couple months without starting it. Today it took a bit to get her to fire, and when she did, super lumpy. I took it around the block and she had little power and was sputtering. Its a 1275 with rebuilt HS4's, tuned properly. Plugs are newish. Do I just need to take her for a long drive and clean the pipes? Or could something have gone wrong just from sitting?
    1960 Bugeye AN5L43788, 1275, Datsun 5 speed, bunches of fun goodies.

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    Yoda dklawson's Avatar
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    Re: Car running poorly

    If it ran well when parked, I suggest looking at the fuel system. Ignition parts typically don't go bad from sitting short time periods.

    I would take the vacuum chamber and piston off one carb, then flush the jet with spray carb cleaner using one of those spray straws. After spraying I would use a pipe cleaner (remember those?) to gently scrub the jet tube out. I would also use a piece of fine ScotchBrite wet with carb cleaner to remove any residue on the needle. Finally I would wipe the OD of the piston and ID of the vacuum chamber with a rag damp with carb cleaner. After putting that carb back together I would do the same to the other one. If you do this by just removing the piston and vacuum chamber you will not have disturbed the jet centering or the mixture. Don't forget to top up the damper oil.

    If that did not address the problem I would take the float bowl lid off one carb and spray carb cleaner through the float valve. After replacing that lid I would do the same for the other carb. Again, this won't affect the mixture but should flush out gum, varnish, and fuel residue.
    Doug L.
    '64 Morris Mini Cooper-S 1275
    '67 Triumph GT6 Mk1

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    Great Pumpkin JPSmit's Avatar
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    Re: Car running poorly

    If it has been sitting and, was running fine before, two thoughts.

    1. ethanol & stale fuel. If you are using regular pump gas you have both. It always takes me a fresh tank of gas to really run right. You can try an additive and maybe something like sea foam.

    2. You might need to add oil to the dashpots.

    But, I would strongly suggest you not tear anything apart until you run some fresher and preferably no ethanol fuel through it.
    John-Peter Smit
    1976 MG Midget
    1969 Vauxhall Viva GT
    1958 Fiat Multipla (Barn art)

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    Jedi Knight bugedd's Avatar
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    Re: Car running poorly

    Thank you California for only allowing ethanol fuel

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    Re: Car running poorly

    I just pulled the plugs, third cylinder back was very wet, looks like it hasn't been firing. Put them back in and pulled the wire off that plug, runs the same. Looks like a dead cap, rotor, or wire. Just replaced the cap and rotor 1000 miles ago. Is there a good way to test the wire without getting shocked? Anything else I should look at?
    1960 Bugeye AN5L43788, 1275, Datsun 5 speed, bunches of fun goodies.

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    Jedi Knight bugedd's Avatar
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    Re: Car running poorly

    Update...just checked resistance on wires, all of them are consistent. With the car running, pull the wire for #3, car ran the same, saw a spark come out of the wire. Now I am confused.
    1960 Bugeye AN5L43788, 1275, Datsun 5 speed, bunches of fun goodies.

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    Yoda dklawson's Avatar
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    Re: Car running poorly

    Move the entire plug/wire combination from #3 to a different cylinder and repeat your test. Confirm that the problem moves with the plug/wire.

    The spark you saw could be occurring at the wrong time if the cap is damaged or if the plug wires are on in the wrong order.
    Doug L.
    '64 Morris Mini Cooper-S 1275
    '67 Triumph GT6 Mk1

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    Re: Car running poorly

    try swapping the plug with one of the others, if problem is still on #3 the I'd suspect a inlet valve problem, maybe a bit of rust on valve seat, do a comp test
    Russ

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