Merc 700 6L vs Merc 650 4L

[mk55h]

Does anyone have any experience with the performance of the 1961 Merc 700 FGS in comparison with the later Merc 650 1966 4 banger.
Which motor had the better topend, how did they compare in gas consumption. I alawys thought the old 700 was a beautiful engine,good lines, and lightweight.

As an afterthougt how did these compare with the later 3 cylinder 70-50's. In 1984, my father purchased merc 60 3 cylinder to replace his original 1960 Merc 400. I swear the old girl was faster. Much nicer sound on the 400. The 600 burnt out the top piston in the second year, whereas the 400 offered 24 years of trouble free running.

[Laker]

Welcome aboard! Do you have a MK55h? Can we see pics?
The 700 I6 is a better motor than the 4cly 650
Similar in CID but the 6 we had on an old century had good bottom end and GREAT Mid range. The 850 4cyl will out run the 700 I6 by a good bit but Both of the 650 4 cyl I ran were total pooches.
I have a Very clean 15 inch shaft 700 I6 for sale If your interested.

[Mark75H]

4 cyl 65's are 60 and 62 ci depending on the year ('66 is 60ci). The 61 70 FGS is 66ci as is the 4 cyl 85. The 85 has a lot of improvements over both of the earlier motors and isn't much of a comparison.....redesigned "Direct Charge" piston crown & head plus the center hinged reeds and beveled crank for more intake flow.


Back to the original question: 700 FGS vs 650. Like most questions, it depends on the boat and the props you have for each engine more than the engine. Bigger boats will probably favor the 700, smaller boats might need the 30 or 40 pounds of weight reduction of the 650, plus the fact that it carries its weight lower.