Re: Merc 850 ground straps
Mostly the ground straps keep the entire engine uniforn under a solid ground. Lets say on a car you don,t have a ground from your battery to the frame but you have it to the block of the engine. The motor mounts are rubber and the only ground connection is the linkage of the transmission. when you shift gears you will see your headlights at night flicker because of the intermitin grounding of the system rather than a direct consistant groundingbeing established. This would create a spark however minimal due to the creation of the ground by the screwdriver to the carb being your grounded. Electrolisis occurs when even the slightest amount of current is subject to an ungrounded part of the engine, and therefore corrosion becomes appearent. If the spark your seeing is a heavy spark I would suggest checking your plug wires for splits or cracks and jumping to a bracket and such. Also make sure you put a consistant ground to the midsection from the block as the gaskets create a barrier between the exhaust plate, and the block, and the exhaust plate, and the midsection leaving your shift shaft and (EDIT)water tube Has a rubber gromet) (Done edit)as well as the exhaust tube which we all know gets build up from exhaust remnants as an itermiten ground that will create electrolosis.The Driveshaft has a layer of lubricant(Greese) that also beleive it or not creates an intermiten ground. Whe your LU and midsection are in the (Ground)water and there is no consistant ground then current runs rampant and eats your lower units parts wherever ther is bare metal touching the grounded water. If you painted any part of the engine make sure the ground is not over paint and contacts with the metal to create a consistant ground. Becauise the lower unit bolt bite into the aluminum it creats a ground for quite some time. But should the bolts build up a barier then your LU would at that point be subject to electrolosis
