60 HP Mercury Bigfoot Performance Question

[suntracker21]

I have a brand new 2011 Suntracker Party Barge 21' Pontoon (two tubes) with a new 2012 Mercury 60HP Bigfoot Motor. The motor has recently been broken in according to Mercury specs. I am unable to attain full throttle (WOT) with the throttle lever pusher all the way forward. The motor runs fine, but doesn't attain the 5500 - 6000 WOT RPM stated by Mercury. The best performance I can attain with one person on board (160 lb.) is 4400 rpm's at 16.2 mph per my Lowrance GPS Fishfinder unit. Mercury says I should be able to hit 5800 rpm's at 22 mph. Needless to say I'm very disappointed. I'm having problems with the dealer resolving the motor issue, but I'm still working on them. The motor is equipped with a Black Max 14" (dia.) x 11" (pitch) aluminum blade (3 blades). The tubes are clean so there is no resistance there.

Does anyone have any advise for me as to what the problem might be as I continue to get the dealer to see the light.

Thanks.

 

[lncoop]

Re: 60 HP Mercury Bigfoot Performance Question

I have an old two smoke, umm, I mean two stroke, so I can't give you any firsthand insight, but it seems like I read somewhere that the plugs need to be changed (and maybe even gapped differently?) after the break in is complete. Have you carefully read your entire Merc manual? Should be some structions in there I'd think.

 

[Psandherr]

Re: 60 HP Mercury Bigfoot Performance Question

I have that same engine and most of the time to get those 22 mph speeds you need a sport model tritoon with under skin and special tubes

These are the boats that mercurey tests on which give unrealistic performances specs for regular toons

 

[BobGinCO]

Re: 60 HP Mercury Bigfoot Performance Question

...new 2012 Mercury 60HP Bigfoot Motor...best performance...is 4400 rpm's...Mercury says I should be able to hit 5800 rpm's...with a Black Max 14" (dia.) x 11" (pitch) aluminum blade (3 blades)...

OK, let's break it down.
WOT should be 5800. You get 4400. You're 1400 short.

Somebody stated that every 2" of pitch you drop will give you 400 RPM increase. This would indicate that you should be going to a 5" pitch prop. This, of course, is preposterous.

Let me give you some insight. My Merc 115 HP 4 Stroke was only hitting 4800 RPM with a 13.75 X 15 prop.
I put a 13.75 X 13 prop on her, and WOT is now 6200. Perfect. Consider, that at my elevation (5,500 feet above sea level), my motor is only putting out about 90 HP, and I have the same lower unit gear ratio (2.33:1) that you do. We're not THAT far apart.

First, I would say there's no WAY you should be swinging a 14" diameter prop with a 60 HP motor, but I would suggest you try a prop with 9" pitch, and see how she performs. I'm looking at Solas website, and their prop selector is coming up with maybe a 1311-118-11 11.75" in diameter, and 11" pitch or a 1311-120-10 at 12" diameter by 10" pitch.

 

[lncoop]

Re: 60 HP Mercury Bigfoot Performance Question

I think I'd read the manual before I started experimenting with props. What is the dealer saying?

 

[James R]

Re: 60 HP Mercury Bigfoot Performance Question

I have recently purchased a used 1997 60HP Big Foot. It came with a 14x13 pitch 3 blade prop. Still cleaning it up but I anticipate it will do well on my 20ft Aqua Patio. If RPM is all you are concerned about using a smaller prop or a lower pitch will do that.
I think you are thinking that the motor is not putting out. A Dyno test is the only way to really know. Ask your dealer to check that the throttles are opening fully. That is an easy one.

 

[JEFFBUZZZ]

Re: 60 HP Mercury Bigfoot Performance Question

i have same boat same motor ,mine is only a few weeks old also .my wot is 5700 at 23 to 24 mph with one person and light gear and half tank of fuel .the correct prop is 14 x 11 ,i tried a 14x9 and lost about 8 mph ,it did bring my rpm up but lost alot of top end speed ,what hole is the motor in by tracker specs it should be in the 2nd from the top ,r u trimming up on the motor or leaving it down trimming the motor up will gain u some rpms . i thought that was low so i moved mine up two holes and i lost 2 or 3 mph ,so i put it back ,when the 20 hour service was done were the plugs changed and at at what gap were they put ,for break in the plugs r set tight ,should open them up about 8thous more ,it sounds to me that ether the throtle cable is not set right or you have plugs set wrong

 

[Jlawsen]

Re: 60 HP Mercury Bigfoot Performance Question

First, I would say there's no WAY you should be swinging a 14" diameter prop with a 60 HP motor, but I would suggest you try a prop with 9" pitch, and see how she performs. I'm looking at Solas website, and their prop selector is coming up with maybe a 1311-118-11 11.75" in diameter, and 11" pitch or a 1311-120-10 at 12" diameter by 10" pitch.

I don't disagree but thought you should be aware of why they do it. The big foot gearcase is there so you can swing a larger diameter prop. The larger diameter prop is there so you have more thrust at lower RPMs for manuevering. That's it in a nut shell. The dealer in this case is probably thinking the same thing. He's probably wondering why someone would give up the added manueverability (docking and loading on a trailer). I do agree that the rpms might seem low and could be damaging for a 2 stroke motor but this is a 4 stroke and will be just fine. Most likely the only solution is going to be more HP. A smaller diameter prop will give you more RPM's on the top end but not much more speed and you'll loose that low rpm manueverabilty.

 

[lncoop]

Re: 60 HP Mercury Bigfoot Performance Question

I do agree that the rpms might seem low and could be damaging for a 2 stroke motor but this is a 4 stroke and will be just fine. Most likely the only solution is going to be more HP. A smaller diameter prop will give you more RPM's on the top end but not much more speed and you'll loose that low rpm manueverabilty.

He's getting 1400 too few RPMs. That's not acceptable. Something's not right, and I could be wrong, but I'm betting whatever it is is on the top half of the motor. Hopefully he'll let us know what's going on.

 

[WaterDR]

Re: 60 HP Mercury Bigfoot Performance Question

Yes, a different prop would get the rpms higher, but should not be used to mask a motor problem. sounds like he has a motor issue.

 

[lncoop]

Re: 60 HP Mercury Bigfoot Performance Question

Yes, a different prop would get the rpms higher, but should not be used to mask a motor problem. sounds like he has a motor issue.

Yes sir. As I said, you can put what I know about four strokes in a gas cap, but from what I've read it just sounds like a post break in adjustment needs to be made. Hope that's all it is, and I really hope we find out for sure.

 

[steelespike]

Re: 60 HP Mercury Bigfoot Performance Question

The bigfoot on 20 21 22 ft pontoons runs 20 to 22 mph.
Log diameter plays a roll in speed.also motor height.
16 is really slow.They should carefully check the setup.

 

[Jeep Man]

Re: 60 HP Mercury Bigfoot Performance Question

I have the same motor on the same boat (minus 1 foot). You have the right prop. I run a 14x11 and get about 20 mph at 5800 rpm. My backup is a 14x9 where I have a top end of 16 mph at 6200 rpm and can go over the recommended max if I don't watch what I'm doing. Have the motor dynoed and likely you need to change the plugs.

 

[Silvertip]

Re: 60 HP Mercury Bigfoot Performance Question

The very first thing to do before spending money on props, discussing the issue with the dealer who apparently is not interested in after the sale service -- is to stick your head under the console and check the TACH pulse setting. You have a prop that is in the ballpark for that engine. Big Foot motors are work boat and pontoon engines which "require" big props. If the tach is properly set (6P) then either the engine is not making full power or there is some excess drag on the boat. 40/50/60 HP Big Foot pontoon motors typically can run 14 x 9 to 14 x 13 four blade pontoon props. Pontoon props (Mercury makes one) have big rounded ears and provide the push a pontoon needs. They also work much better in reverse than a standard three blade prop.

 

[okichewy1]

Re: 60 HP Mercury Bigfoot Performance Question

I have a 2005 Mercury BF 4 stroke 60hp motor on a Sun Tracker fishin' barge 21' pontoon and can only get about 4900 rpms with a 3 blade 10pitch on it. Any suggestions? I am going to change the plugs like most said on here today and run it.

 

[Old Screwball]

Re: 60 HP Mercury Bigfoot Performance Question

We just bought an 18' Sun Tracker Party Barge. We bought an 18' because it will fit in my garage when stored. I opted a 75hp 4 stroke Merc, the largest engine allowed on the transom. After experimenting with 3 props (from a previous boat) I settled on a 14 X 13. WOT is 6000 RPM and I hit 24.6 mph with 4 adults and 2 grandkids. I can hit 30mph with just me. When I 'propped up' to a 15 stainless pitch I could only hit 4400 rpm and less than 20mph. Somewhere on one of the other "My pontoon is too slow" threads, a member published a chart comparing motor size, RPM and he was right on with estimated speed. Something to remember, pontoons aren't fast, just a ton of room and very comfortable.

Good Luck!

 

[steelespike]

Re: 60 HP Mercury Bigfoot Performance Question

Check that the throttle opens all the way. Motor is 8 years old.Be sure it is in excellent tune with good compression.
It would help to know your speed at 4900.Perhaps the tach is wrong.You can't make up 1100 rpm with a prop change.
Typically 10" or 11" prop and about 20 mph. at 5700-6000.

 

[lakegeorge]

Re: 60 HP Mercury Bigfoot Performance Question

I agree with a few others, you have an engine problem, not a prop problem. Something is not right with the motor and I would demand that the dealer fix it. If not contact Mercury, I did when I had problems and they sent a service mgr. to my dealer to correct the problem.

 

[airdvr1227]

Re: 60 HP Mercury Bigfoot Performance Question

Before you go around demanding things how are you measuring your speed and RPMs? Boat gauges are notoriously wrong.

 

[Rancherlee]

Re: 60 HP Mercury Bigfoot Performance Question

I'm betting on the throttle not opening all the way, is there a lot of movement on lever after putting it in gear before it starts throttling up? A 14x11 should be the perfect prop for a 2.33 gear case 60hp engine on a pontoon and 21-22mph should be expected with a light load. If you had a bad plug or misfire you would feel it on a 4 cylinder 4 stroke as there would be a noticeable vibration.