2001 Mercury 60hp Bigfoot

[harmanoff]

I am currently in talks with possibly purchasing this motor that is in the title. It is coming off a 26 foot pontoon boat and going to be going on my johnboat. My johnboat is long shaft ready as far as the motor mounting on the transom. Question is, I was told I would need to get a different prop for the motor since he’s going on a John boat instead of a pontoon boat. I don’t know this for sure. I was just told by the old mercury mechanic in our town. So I’m seeking advice on this. The motor As less than 20 hours on it as well. Which I know is a shocker. But an old man owned it and hardly ever used it.

 

[racerone]

This " old Mercury mechanic " is correct.----It seems that young folks do not know simple basics these days.---Sorry , my observation.-----First you need to post what is on the motor now.-----Then test the motor on YOUR boat to determine the correct prop for it.-----Thank that --- old Mercury fellow ---for giving the correct advice.

 

[harmanoff]

Lol...sorry wasn’t meaning it in anyway bad. He’s not old just doesn’t do it anymore. I have never bought a newer motor only had mine given to me from my grandfather. Sorry I do t have the knowledge I guess I should magically have. Hence why I asked here. I will post back what is on there this weekend when I go see the boat.

 

[QBhoy]

Yeah. If the pontoon boat was properly propped...there is a 99% chance you’re going to need to re prop for your jon boat. Be aware that in those days...big foot was made for and engine to push heavy boats with a punch above their rated HP. So had usually a larger gear case and bigger diameter of prop to suit. Might need to think around that too perhaps.

 

[ahicks]

Lol...sorry wasn’t meaning it in anyway bad. He’s not old just doesn’t do it anymore. I have never bought a newer motor only had mine given to me from my grandfather. Sorry I do t have the knowledge I guess I should magically have. Hence why I asked here. I will post back what is on there this weekend when I go see the boat.

Don't worry about your question. You're right about this being a good place to ask. Just consider that as you age, it starts getting tougher to stay "politically correct", or even care if you are. You say what's on your mind and move on. In other words, you get to the point where you have so much information stored up, you have a free to be grumpy pass... -Al

 

[Texasmark]

I assume your boat is a flat bottom, aluminum, open construction, cross seat, engine operated from the rear seat with an attached tiller handle, or possibly a side mounted console mounted just forward of the rear cross seat with a steering wheel and remote controls type boat used for things like running catfish lines or river fishing type outings. Also assume, for 60 hp that it would be at least 16' long and have a beam of around 5'. Additionally I suspect you will be frequenting shallow, sand, timber or vegetation infested water, and a power trim unit would come in real handy for gliding over mossy areas, or sandbars and such.

With all that in "my" mind, I'd say look elsewhere for your engine. Your lower unit is probably off a 90-125 HP 3 or 4 cylinder engine, specifically setup for pushing much heavier loads than designed for the normal 60 hp engine and the prop is probably between 13 and 14" in diameter (143 square inches of area) and the increase in size and weight of the engine casting(s) to support that size of prop, rather than the smaller size, and lighter weight 10" diameter (78 square inches) prop common on 60 hp triple loopers with the LU designed for that HP range. It will become your biggest PIA over the years due to it's size.

 

[ahicks]

60 hp Bigfoot is a pontoon boat motor. It doesn't use the bigger lower unit used on the 75-115 hp motors. It does use a high thrust gear ratio (my understanding)...

 

[Texasmark]

60 hp Bigfoot is a pontoon boat motor. It doesn't use the bigger lower unit used on the 75-115 hp motors. It does use a high thrust gear ratio (my understanding)...

Well sir I posted my understanding. I assume Merc got the idea from Scott Atwater back in the '60's where they had a 14 HP powerhead connected to one of their larger engines, 40 twin, 60 or 75 HP triple, lower units. Amazing what 14 HP could do with that and knew of at least 2 on toons....and recall seeing one on an outing and the toon was clipping along at a nice clip...much faster than trolling speed.

Whipping out my 1997 Merc. sales catalog, in the mid range section its titled: "60, 60 Big Foot, 50,40,30". At the bottom of the listing it shows a picture of a generic lower unit, no dimensions, prop looks more like a weedless prop as a frontal view shows the blades folded back from the root significantly....not straight out, like pedals on a flower akin to most general purpose props. It does state "The Big Foot 60 HP model does feature a beefed up lower unit and a lower gear ratio for added torque." Well if you are going to lower the ratio you are doing that to swing a larger diameter prop with less pitch for increased thrust over the regular unit.....so going from 10" to 13" surely would be sensible and that puts you into the 60 Jet thru. 125 HP engine class.....and you are interested in increasing thrust because that is what pushes the boat, not torque per se when it just overcomes the resistance of the medium and becomes HP by revolving.

That means to me that you are adding cogs to the circumference of the driven shaft (the prop shaft) so you need extra room to do that unless you reduce the number of splines on both shafts, or their size, to fit the existing LU castings and what does "beefed up" mean if you are using the same LU casting, and that's going the wrong way for torque increasing dimension.....soooo, one would expect that to keep costs down, they would just grab something off the shelf and change the bottom of the midsection casting, maybe just a special adaptor casting connected to a short shaft midsection coming out with the regular long shaft dimension of 20" to accept it and change out the 1.64:1 gears to something like the 90 HPs 2.33:1, swinging the 13+ diameter props in that LU since they will fit. But all this is purely armchair speculation and subject to error as finishing this I will be headed for bed.

But blabbing on here kills time in waiting for the sun to come up and the start of a new glorious day.

 

[harmanoff]

Ok slight correction, its a 2002 60HP bigfoot, nothing has been changed from its original purchase date. no new lower units or whatever. It fits on my boat beautifully and looks fantastic on the boat. My boat is a 18ft 6in Lowe Olympia 5 or 5 1/2 foot wide with a steering column. Also my boat is long shaft ready, all that was considered before i bought it. it has barely any hours on it maybe 20 at most. I am just looking for prop suggestions. so anyone have any? my mercury guys around my area are of little help, one said he had one in stock that would be good but yea wanted to ask others here and see what i got

 

[harmanoff]

also the only really shallow areas ill be in are heading to the beach, i fish is mostly deeper areas and stuff like that, no issues

 

[WesNewell]

You'll find a good starting point here.

Mercury Marine - A Worldwide Leader in Marine Propulsion | Mercury Marine

Manufacturers of outboard motors and MerCruiser inboard engines, with over 4000 dealers in the United States.

www.mercurymarine.com

 

[Texasmark]

Let's start with a gear ratio. If you don't know an example would be 2:1 used on my current engine. The flywheel makes 2 complete revolutiions for one complete revolution of the prop.

Mark a reference, starting point on the flywheel (spark plugs out makes it easier) and on the prop. Start turning the flywheel and continue till the prop has made one complete revolution. Count the flywheel rotations.

On partial revolutions, take a sewing cloth tape and measure the circumference of the flywheel. Call that dimension A. Then measure around the flywheel the distance that didn't complete a full turn. Call that dimension B. Ratio is number of full revs plus B/A. I'd expect your answer would come out 2.33:1.

Boat something like this...name changed since then: https://www.loweboats.com/hunting-boats/roughneck-1860-big-river/

Guessing again 3 cyl looper, Wide open operating range 5000-5500 RPM. Guessing a 13+ inch diameter prop fits the LU...(divide by 2 subtract 1.4" for the radius from the Anti Ventilation plate to the center of the prop shaft for fit). Guessing on that boat prop slip wouldn't be over 10% so I'll use that.

Go-fast.com prop slip calculator, dialing in for the correct pitch shows:

My gut feel is 13+x15P, 3 blade, 15 spline, aluminum...iboats sells them go to parts, props, enter the data for your engine and make your selection.
First guess for that and 10% slip and 5300 RPM at wide open throttle, best trim/tilt angle, boat loaded to suit decent speed...not bow heavy, would be 29 mph.....a good speed for a flat bottom, aluminum fishing boat. If something magically happened and your rpms went on up to 5500 design max, then your speed would increase to 31. If your slip was no more than 7% you could squeak by at 32 for 5500.

That's what I'd do with no prior reference for a place to start. These props run about a hundred bucks and sometimes free shippig so you aren't out a bundle if you miss your guess. If 15P puts you below mid mark.(5250 RPM) with the 15, you need to drop on down to 13 or so. Usual RPM change used on this forum is 150-200 RPM change per inch of pitch change.

Gotta remember a lot of things can affect what you get out of the prop you select. Sometimes you can have unsatisfactory performance only because the tilt wasn't set right, or you loaded the bow or stern of the boat too heavy, or the boat is overloaded, the hull is full of barnacles, or slime, on and on.

 

[Texasmark]

Well It didn't make sense for Merc to design a special LU just for the 40 thru 60 hp Big Foot. So here are a couple of www sites to backup my 2.33 and the Solas Amita 3 blade, aluminum (to pick one to fit my guessing also), 15P 13+ (13 1/2 actually from iboats no less) pitch. So if these two parameters don't smell like the 90 HP (maybe the 75 also) lower unit, I'll eat my hat:

http://www.sale-sports.com/products/Mercury-60EXLPT%2dBigfoot-Outboard-Motor-Four-Stroke-BigFoot.html

http://boatpropellers.iboats.com/Me...-135-15_Propeller/815/7293/?cart_id=881825565

From the full iboats listing: http://boatpropellers.iboats.com/Me...15.00-Pitch_Propellers/815/?cart_id=881825565

 

[JimS123]

A Bigfoot is basically what they call a Command Thrust today. It is indeed a larger 115 gearcase with different gearing and was originally designed for heavier slow-moving boats like pontoons. But today they are being marketed for many other applications. They are more durable, easier to plane and can use a wider selection of props. I don't think they stick down lower in the water, but they surely are a bit wider.

Sounds like a good deal for your boat. yes, you will need a different prop, and you will have many to chose from. Look up Mercury's prop selector tool and you'll come pretty close on your first try.

My only concern would be that your little jon boat is capable of a big 60 4-stroke. Check the boat's capacity plate before you proceed.

 

[Texasmark]

A Bigfoot is basically what they call a Command Thrust today. It is indeed a larger 115 gearcase with different gearing and was originally designed for heavier slow-moving boats like pontoons. But today they are being marketed for many other applications. They are more durable, easier to plane and can use a wider selection of props. I don't think they stick down lower in the water, but they surely are a bit wider.

Sounds like a good deal for your boat. yes, you will need a different prop, and you will have many to chose from. Look up Mercury's prop selector tool and you'll come pretty close on your first try.

My only concern would be that your little jon boat is capable of a big 60 4-stroke. Check the boat's capacity plate before you proceed.

It seems that in 2014 and the dawning of the CT engine, they went to a single OHC and long stroke to get the torque up for hole shot and cruising applications along with the 2.33 gearbox and 13+" prop. So in that regard, they are different than the earler model Big Foot engines....so I read.

 

[Faztbullet]

The OP 2001 60Hp is a 'baby L3" motor with the 75-115Hp metric lower unit. Same unit that has been used from 1991-2014 in 2:33:1 ratio.

 

[Texasmark]

The OP 2001 60Hp is a 'baby L3" motor with the 75-115Hp metric lower unit. Same unit that has been used from 1991-2014 in 2:33:1 ratio.

Thank you sir. I was wondering when you were going to add to this for some validity.

 

[harmanoff]

That’s for all the info. It’s actually a 2002 lol. I went to our local Mercury dealer/mechanic and told him my boat length and the motor he suggested a 13 x 15P prop. It’s the Mercury brand for the Bigfoot/command thrust motors. He said if my roms are to high or performance isn’t what I like bring it back and can swap me out for a different prop. Had it out over the weekend to test it out. Up river on the Mississippi I get 30 mph, down river I got to 34mph. I got a digital rpm gauge but it was terrible so sending it back. Gonna get a regular tach but would like recommendations on that as well. So that way I can be for sure on my rpms and all that. Btw it fits the John boat great not to heavy and loving the tilt/trim feature. Got it trimmed out to where with just me in the boat there wasn’t much of the boat in the water!!!

 

[WesNewell]

Mounted at the proper height with your boat being under 1000#; you should get ~38 mph with a light load and an 18P prop doing ~5800 rpm. As for a tach, no matter which one you get, make sure it is set properly. This is according to he Merc prop finder. 1000# boat, 400# load, 12 Gal gas.

 

[harmanoff]

My boat weighs at most 500lbs atleast that’s what my dad said. I’ll wait for the rpm gauge to get in then and go from there