Re: Mercury Force and US Marine (Chrysler) Force Engines
Mercury took a perfectly good engine design and ruined it! LOL
Seriously: US Marine was the Force that was bought from Chrysler when the company was bailed-out by the feds in the early 1980s. Basically, the only changes they made to the white ones were the graphics on the cover. US marine was a company in the AMF-Brunswick group which made Bayliner. That's why you typically see Bayliners with Force power. They were sold as a package.
The blue Forces were changed in the ignition and cowling to give a more updated appearance and a cheaper to produce ignition system.
Sometime in the late 80s Mercury got involved with Force--I forget who bought who-- but Mercury started making changes in the lower unit, the cowling, and in the later years, they changed the controls. The mid leg and lower unit became Mercury design. The 4 cylinder engine blocks remained substantially the same, but the three cylinder 70 and 75 HP engines had a redesigned manifold and intake system. Carbs remained Tillotsen. Mid to late 90s Force engines had Mercury ignition systems which were probably superior to the Prestolite designed Force systems.
Quite frankly, some of the changes Mercury made, I considered beneficial. However I also disliked some other changes they made. Some things were good engineering design, and others were made for the sake of cheaper production costs--it's obvious when you compare engines.
The final outcome is that almost any three or four cylinder block is swappable with a little finessing as long as you pay attention to when Merc changed the lower unit to Merc design and changed the splines in the crankshaft.
