Re: 35 Eight Packard starting problems

Posted by Owen_Dyneto On 2013/3/1 12:05:22

You can purchase quite inexpensively a spark plug cleaner. They use an abrasive grit and are powered by compressed air. A good purchase if you're in the hobby for the longer haul. I haven't looked recently but Eastwood had them at one time, and I've also seen them on the shelves at auto parts stores.

PS - I couldn't quite read the plug number - what are they? I'm asking because they are obviously burning very poorly but I can't tell if the deposits are mostly oil or carbon and it would be nice to know if the plug heat range is appropriate for your engine.

PPS - taking a closer look, is it UY6? If so that would be the hotter of the 10mm plugs, equivalent to the AC M8 (the AC 104 being the cooler plug). That would have been the recommended plug for "light service", the cooler one for "heavy service" so I don't see any issue with the plug choice. If the deposit is black and dry (not black and oily) it suggests fuel problems back when the engine was last running - an extremely rich mixture perhaps due to a failed carburetor needle and seat or a failed float. I'd either replace the plugs or clean them and give it a try. When all is right with the world, the porcelain insulator on the center electrode should be a light tan color and no significant carbon or oil deposit.

If it starts up with new or cleaned plugs, after a short time remove a plug and check for carbon build-up. If YES, you have a fuel problem perhaps in the carburetor or perhaps from an electric pump putting out excessive pressure. The 33-39 AC fuel pumps were very capable and rebuild parts or services commonly available - if you were using an electri pump exclusively I'd stop doing that and if you must use it, use it just for priming after storage and make sure the mechanical pump is up to snuff. After that, check the carburetor.