"Bigfoot" Question

[Blake0912]

I have a 1992 40hp Merc 4cylinder on the back of my '13 whaler, I was looking at some parts catalogs and noticed theres a "bigfoot" model of my motor. What exactly make a motor a bigfoot? I would say my motor is a long shaft. So how do I determine if mine is a bigfoot or just a normal 40hp. The boats in storage at the moment so i don't have the serial numbers on me, but heres a pic of the motor.

 

[carholme]

Re: "Bigfoot" Questoin

Re: "Bigfoot" Questoin

Blake;

The following description of a Bigfoot is taken from a sales brochure:

A Mercury BigFoot is the ideal powerplant for specialised applications such as houseboats or pontoons, where the prop needs to sit much lower in the water.

Mercury's BigFoot design delivers more control than competitive motors. With traditional boat hull design, a boat slices through the water allowing the engine to work in fairly undisturbed water. With a pontoon, the twin tubes under the hull forces turbulent water toward the engine. Mercury BigFoot's larger and taller gear case, larger propeller, and oversized anti-ventilation plate means that you get more leverage from the propeller. All this adds up to better handling manoeuvrability and performance.

BigFoot's larger components also provide additional strength and greater durability. For example, all gears are 33% larger than competitive outboards to reduce engine stress and maintenance requirements.

Gerry

 

[Maxz695]

Re: "Bigfoot" Questoin

Re: "Bigfoot" Questoin

looks to be a long shaft as far as the bigfoot I couldn,t tell you. I do have a flywheel and a good stator from a 1997 that may fit this if you find you need it anytime soon of course it,s not exactly free from 40 HP 4 cyl 4 stroke oil injected engine I have the numbers good luck on the bigfoot info/ can you measure down my 2 stroke 40 HP 2 cyl is about 13 1/2 from tail to center of the prop this looks lower than mine but if it measures like 14 + it,s more than likely a bigfoot. hey carholme no disrespect but if you put a LU up in drive and someone accedently turns the key while your hand is in the bigfoot what would happen?

 

[Blake0912]

Re: "Bigfoot" Questoin

Re: "Bigfoot" Questoin

Its definitely a big 40hp. Theres no "bigfoot" marking on the cowling, the only thing is says besides Mercury is "classic" on the front near the oil cap. I remember the last time it was in the shop the mechanic put the "wrong" stator on it causing the motor to run horribly, but later he found out that theres two models of a similar engine and he just happened to order the wrong one, swapped the stator out with the correct one and it ran like a champ. So that leads me to believe that it may be a bigfoot due to the fact that the guy ordered a stator for a standard 40hp. Or i could be dead wrong. Any info would help.

 

[Maxz695]

Re: "Bigfoot" Questoin

Re: "Bigfoot" Questoin

is this an oil injected engine if not then there is another 40 HP I stripped but the LU was gone and the motor through a rod probably because of the oversized gears and prop of a bigfoot, as well as lack of oil

 

[Blake0912]

Re: "Bigfoot" Questoin

Re: "Bigfoot" Questoin

Yes this is an oil injected engine.

 

[Maxz695]

Re: "Bigfoot" Questoin

Re: "Bigfoot" Questoin

again I ask you to measure from the tail of the outdrive down to the center of the nut that hold the prop on BIGFOT can hold a bigger prop and has bigger gears in the LU MY measurmetnts are as follows 13.5 down from the tail to the center of the prop SHATF. if the measurement you get is in excess of this measurment then you have a bigfoot LU

 

[Blake0912]

Re: "Bigfoot" Questoin

Re: "Bigfoot" Questoin

The leg itself is around 17.5 inches. The lower unit is 15.5 inches and the serial number is od162220.

 

[Maxz695]

Re: "Bigfoot" Questoin

Re: "Bigfoot" Questoin

If you did like i asked and measured down from the lower unit tail to the center of the prop bolt and gave me the measurement being much more than 13/12 inches i could tell you it,s a big foot A bigfoot goes lower in the water accepts a "QUOTE" (BIGGER PROP) than if the measument is more than 13 1/2 inches say more like 15 16 17 inches it,s a bigfoot hope this helped

 

[Blake0912]

Re: "Bigfoot" Questoin

Re: "Bigfoot" Questoin

Guess i'm dumb and misread your post, sorry. According to my measurements its only 7.5 inches from the "tail" to the center or the prop bolt assuming we have the same definition of "tail". Is there a sure fire way to determine it just by the serial number that you know of?

 

[Maxz695]

Re: "Bigfoot" Questoin

Re: "Bigfoot" Questoin

that makes 15 inches of prop space my 40 hp is 7 1/2 so i doubt it,s a bigfoot. i,m no expert on this but I know I do not have a bigfoot but sure would love to have it i lowered my jackplate all the way and still higher than i need to be. I,m going from a 12 x 11 pitch to an 11 x12 to lighten the strain on my engine and get more RPM keep looking itno it though sorry I couldn,t tell you what you want to hear

 

[Blake0912]

Re: "Bigfoot" Questoin

Re: "Bigfoot" Questoin

thanks for your responses i appreciate it, i'm sure i will figure it out eventually.

 

[Maxz695]

Re: "Bigfoot" Questoin

Re: "Bigfoot" Questoin

I re-measured my distance and came up with the result i gave 7 1/2 inches short shaft same as yours that is why they came up with the bigfoot but for engines with more HP.to make a short shaft first of all longer. A bigger prop would strain a 40 HP and bog it down seriously unless it had like a 8 pitch or less, depending on the gear rtio of the bigfoot itself musta been one hell of a special 40 HP for this to be installed on by the factory

 

[Blake0912]

Re: "Bigfoot" Questoin

Re: "Bigfoot" Questoin

Guess my question is answered, i just have a standard shaft. Mine came with a 12p prop from the factory.

 

[Maxz695]

Re: "Bigfoot" Questoin

Re: "Bigfoot" Questoin

View attachment 90324like this ?

 

[Blake0912]

Re: "Bigfoot" Questoin

Re: "Bigfoot" Questoin

yup

 

[Maxz695]

Re: "Bigfoot" Questoin

Re: "Bigfoot" Questoin

sorry to break the news but at least now you have the answer. Sometimes I,m right but sometimes I,m wrong at least I can admit that

 

[Blake0912]

Re: "Bigfoot" Questoin

Re: "Bigfoot" Questoin

Its all good, I just wanted to know in case i have to order parts or a new prop in the near future it was just bugging me. But i do love this motor, only problem it ever had was when the stator went bad but other than that its a champ. Thanks for your help. oh btw do you know if i run a different prop if it will help me with the planing, when i have 2 or 3 people and some gear in the boat it has a hard time getting on plain, i usually have to stand up and push down on the bow a bit for it to level out. Any insight on this?

 

[Maxz695]

Re: "Bigfoot" Questoin

Re: "Bigfoot" Questoin

ill sell you my prop if my 11 X 12 i,m going to change to a 12 X 11 works out good i,ll know in a week when my new water pump complete and my new prop show up in the mail. Just want more RPM faster plane and less vetilation (Cavitation) 17 foot procraft bass boat lowered my jack plate so far that I hav to turn the engine to lift for tow. View attachment 90325 droped it 2 inches to lowest setting runs good but venmtilates on turns (Sharp) good luck message me if interested. don,t forget I have 3 of four ciols stator flywheel staor adaptor and other parts from a 1997 4 cyl 4 cycle as wellView attachment 90326View attachment 90327 super cheap you can get all this for under 125 and shipping

 

[Faztbullet]

Re: "Bigfoot" Questoin

Re: "Bigfoot" Questoin

Easy way to tell if a "Bigfoot' is the water pickups. If they are in the middle of housing it is standard unit, if about 2" from leading edge of unit its a bigfoot.