Mercury fourstroke 60 HP bigfoot

Dalfred Ross · Posted: Fri Sep 07, 2007 11:24 pm Post subject: Mercury fourstroke 60 HP bigfoot

I own a 1986 C-Dory classic with a rebuilt 1986 Evinrude 70 HP 2 stroke engine. I will repower soon and my local outboard dealer who carries Suzuki and Mercury has suggested I consider a fourstroke 60 HP bigfoot engine. He says that I will get as much or more power and that the engine is geared to turn a larger prop which should work well with my boat. The weight of the Merc is only about 20 lbs heavier than my current engine. Does anyone out there have any experience or opinions about the Merc bigfoot?

thataway · Posted: Sat Sep 08, 2007 12:19 am Post subject:

I think that you will be dissapointed with the 60 hp engine. The only reason is if you only want to run at low speed. The "Big foot" 60 will swing a 14" prop. A Suzuki 90 will swing a 13 3/4" prop, for all practical purposes the same diameter.

Although some folks like the 70 hp engines, the trend is to the 90's which have considerably more power and probaly will have about the same economy at speed. Your top end will be limited by the "Big Foot"--the Suzuki or the new Honda will be faster and probably more economical, because you are at a full plane.

Dalfred Ross · Posted: Sat Sep 08, 2007 9:55 am Post subject: Hp comparison

Part of what I am curious about in my question is how the new HP ratings compare with my old 70HP? None of the liturature I see says much about torque for the new engines either.

Capt. Jim · Posted: Sat Sep 08, 2007 1:40 pm Post subject:

Were you happy with the performance with the 70 2-stroke? The 60 Mercury 4-stroke is an excellent motor and has a very good power to weight ratio, but should be a little slower.
If you want more speed and power the 90 Mercury Optimax is an easy upgrade as it uses the same instruments and controlls. Would your dealer allow you to sea trial the 60 first and switch if you are not satisfied?

thataway · Posted: Sat Sep 08, 2007 6:50 pm Post subject:

You don't often see torque on the outboard's sites: The Merc big foot is a 60.8 Cubic inch displacement engine. This is the same block as the 40 hp.
If you want to stay with Merc--then look at the 75,90,115 series, which are on the next size up block which is 105.7 Cubic Inch displacement. A 105.7 cu in displacement engine will have very significantly more torque and "power" than a 60.8 cu in engine--both are 4 strokes. If you go to the 2 stroke mercs: then 92.96 cu inch is the number for the 75 to 115 series--the two strokes make more HP per cubic inch (generally) than the 4 strokes. Either way--the 60 hp "Big Foot"-- is going to be a "small" engine for the 22 C Dory. It does have a lower grear ratio, so you can swing a bigger prop...but HP is HP--the bigger prop will be slightly more effecient. But the 75 thru the 115 Merc 4 strokes all use the same gear ratio as the "big Foot"...