Re: Mercury Force VS. Chrysler Force???
First, there were no five cylinder Chrysler 150 engines ever made. They did make a 4 cylinder 150. If you see one of them for a reasonable price, jump on it: they are not too common.
There is no such thing as a Chrysler/Force! That is a misnomer. --A common mistake that a lot of people make because the Chrysler engines were almost completely unchanged when the name was changed. Chrysler was forced (no pun intended) to divest its marine division and sold it to AMF Brunswick, (U.S. Marine) which changed the name to Force. THEY made a 5 cylinder 150. Although it used the same bore/stroke and cylinder liner/porting It was a completely new block--similar to Chrysler design. Later, Mercury bought out Brunswick and continued the Force name for a couple of years more.
It came in two versions: early models were 3.3125 bore, some with 1 5/16 venturi WB carbs and later models were 3.375 bore with the bigger 1 5/8 venturi TC carbs. So, you would expect slightly better performance from later Mercury manufactured Force engines.
As to whether earlier or later model 5 cylinder engines were prone to melting pistons: No outboard can survive a lean run. Lean running from any cause will very rapidly result in melted pistons--in any engine --any brand. As will overheating. I can't tell you how many melted pistons I have replaced in Johnson/Rude and Merc/Mariner. The "Tower of Power" in line 6 cylinder Mercs were notorious for melting the top piston because the water flow to the top cylinder was marginal.
acks coils etc.Chrysler came first then a name change when US Marine(bayliner) took them over.Then Mercury bought them and started using their technology on them.
