Mercury Big Foot What does it mean?

[w2much]

I recently came across a 2006 9.9 Mercury 4 stroke engine A BigFoot. What does he designation Big Foot mean?

 

[Scott Danforth]

heavier duty lower unit meant for heavy loads. the 9.9 big foot would be a good pairing on a pontoon.

 

[racerone]

Agreed----They sometimes use a different midsection / bigger lower unit / with bigger prop / different gear ratio on some motors.----Ideally suited for bigger boats / slower boats / heavy loads.------The marketing department selected the term " big foot "-----The 9.9 may use the 20 hp lower unit as an example.

 

[Fun Times]

The mercury marine bigfoot means the lower gear case housing and internal workings are a bit larger than the standard size gear case housing. Also you'll want to know Mercury has recently changed the name from bigfoot to Command Thrust.

https://www.youtube.com/watch?v=pZFDAetHRIQ

 

[w2much]

Thank you for your reply Scott. IS the gearing different ? Does it turn out the same RPM? Is it not advisable to use as a main power on a small aluminum boat? I am looking for a prop for it, the four blade is shot and am wondering if a higher pitch 3 blade prop will work better for my application. It was previously used as a kicker on a 20 foot or so Whaler.

 

[racerone]

Post # 2 says that gearing may be different.----And there are websites where you can check out those gear ratios too.

 

[robert graham]

Rugged as a Yeti or Sasquatch?....

 

[robert graham]

Rugged as a Yeti or Sasquatch?....

 

[roscoe]

Thank you for your reply Scott. IS the gearing different ? Does it turn out the same RPM? Is it not advisable to use as a main power on a small aluminum boat? I am looking for a prop for it, the four blade is shot and am wondering if a higher pitch 3 blade prop will work better for my application. It was previously used as a kicker on a 20 foot or so Whaler.

.



Size / weight of your boat ?

It appears that motor had a 5000-6000 rpm range, and a 2.08 : 1 gear ratio.

9.9 BigFoot, had a 2.42 : 1 gear ratio.

Yes the engine will run the same rpm, but the prop will turn slower with that gearing.

It should be fine on a 12 - 15' boat, with the right prop. 3 blade should work.
If you boat is a bit heavy, perfect.

If your boat is very light, and you don't need the extra gearing, you could see an approximate 15% loss in top speed.
So, a few mph loss.

 

[w2much]

Thank you all for your replies.

 

[QBhoy]

That engine would be intended for use on a heavier than normal application. Designed to give maximum kick and thrust to a large boat, despite low HP.
Example would be as a auxiliary engine for a sailing boat.
As mentioned they have a more robust gear case than normal and different ratio.
The larger 60hp versions actually use the geaecase from the bigger V6 engines and 100hp upwards and similar.
Wont be as hydrodynamic or perform as well as the normal version of used on a lighter planing hull, but they sure accelerate well.