You didn't state what kind of quad you have, but all quads don't have a decompressor cable. No, the decompressor just makes it easier for the engine to turn over, while starting. I would say the cylinder bolts all have washers, but I doubt it's a big deal if they are missing. It shouldn't make that much difference. As far as liquid gasket sealer, if you are referring to RTV sealant(silicone gasket maker), too much can cause you problems. When the parts are bolted together, the excess that squeezes out on the inside of the engine, will cure and then it can break loose on the inside of the engine. When it cures, it is rubbery and can stop oil pumps up or block oil drain holes, etc. I learned that the hard way years ago when I first started working on ATVs. I will only use Hondabond, now. Hondabond doesn't cure rubbery and is about the same price as RTV sealant. You can buy Hondabond at your local Honda dealer for about $6-$7 for a tube. I highly recommend Hondabond. I even use it on automobiles. Even when using Hondabond, you just need a thin coat.Why wouldn't my Qaud have a starter decompressor cable? Is it nessasary? Are all the cylender bolts sopposed to have washers? Liquid Gasket sealer was used and way way too much was used what problems can that cause? What sould I look for?