Re: '57 Johnson 18hp problems
1. Check for signs of water intrusion into the cylinder (IE, a blown head gasket). It should be fairly obvious by looking at the spark plugs but a compression test might show too. If that doesn't turn up anything, check the lower unit oil for signs of water.<br /><br />2. It sounds like you are missing the brass packing nut for your low speed needle. Is this the case? To get the bushing to grip again, score the outside surface of it with a sharp chisel with a tap from a hammer. This is called "staking" and is how the bushing was originally held in. I suppose you could use a loctite red too, but usually it's best to shy away from goops with carbs. If you are missing the packing nut & packing, you'll never be able to get the engine to idle right.