posted 09-14-2004 11:51 AM ET (US)        

The boat is excellent and everything we expected. The Bigfoot motor performs very well. but it is not everything that was expected. My experience with 4stroke enginess has been two Honda 25-HP models and a Yamaha 40-HP. In comparison the Bigfoot 60 seems much louder at speed.

The package we received has the Stainless Steel Vengeance 14-inch prop. When we test drove the boat I was concerned with the clutch rattle in slow shifts out of neutral. The dealer said they'd get rid of it, but when delivered the excuse [for it still being there] was that Mercury and Boston Whaler both said it was normal. Presumably it is because aluminium propellers run in a rubber hub and the SS propellers do not. When I read the owner's manual it states that the engine should not be used with a SS prop, as this is will cause excessive clutch rattle, although it will not be detrimental to the engine or prop. Hmmm...

My solutions seem to be to re-prop with an aluminum Black Max, or in looking at the Mercury website, I can retrofit the Flo Torque II? I am further confused as the website also states that the Flo Torque comes with the Vengeance prop. The boat is currently on the other side of the country at our cottage so I can't check.

Can someone tell me if the Whaler package includes the Flo Torque hub? If not, will this solve my rattle or should I head to the aluminium props?

The other problem with the engine is a high pitched whine/whistle that comes and goes at various RPM and in various volumes - sometimes quite loud. I called Canadian Customer Service and they told me the whining/whistling noise has been reported by several customers. They have "checked with engineering" and "it is part of the nature of the unit - it's just the way it performs."

So is this a great performing, loud, rattling, whistling, 4-stroke? I'm very happy with the way it performs and it is a great match for the hull--it just doesn't seem very refined relative to the smaller Honda and Yahama motors.

Thanks for a great forum, I appreciate your input

posted 09-14-2004 02:32 PM ET (US)            

I am not sure how much better the Bigfoot will perform with a SS prop, or if it is really necessary. I did notice at a boat show that a dealer had put SS props on a number of smaller Whaler models that were on display. This may have just been a way to increase their profit margin. I also think that sometimes a factory prop may get lost in shipping or otherwise used for service with another engine in a dealership. If the original factory prop gets separated during life on the sales floor, they may just put on whatever is available.

I get the rattle and chatter regardless of which aluminum prop I have on my engine.

If you get too much of a runaround from a dealer, contact Boston Whaler Customer Service direct. They can quickly get you the correct information and provide great assistance when the dealer won't.

posted 09-14-2004 06:10 PM ET (US)            

Thank you for setting the record straight.

posted 09-14-2004 06:11 PM ET (US)            

I have talked to Mercury customer service but they could not answer my rattle question, although they did tell me the part number for the Flo Torq II that could be applied. I am confused at to whether this is already on the engine, or what the dealer told me is accurate and there is no rubber dampening and the rattle is metal to metal contact.

posted 09-14-2004 08:36 PM ET (US)            

The quicker the better on shifts. No finesse needed here.

Rich

posted 09-14-2004 11:10 PM ET (US)         

The aluminum props for the 40-60HP 4-stroke BigFoots are silver painted special ones with a pressed in, soft rubber hubs to prevent rattle. It appears there's a Flo-Torq III hub designed to reduce rattle on these engines using props with the replacable hubs.

Go to http://www.mercurypartsexpress.com/PartsExpress/HomePage/homepage.asp

Click on the link "outboard and sterndrive propellor"

Enter your Zip Code in the Dealer Locator

Select a Dealer in the Dealer Locator

Click on Propellor Hardware and Accessories

Click on Flo-Torq II, III, & HD Hub Kits

Click on Item 3, which should be part number 835257K_9 (Flo-Torq III Hub Kit)

Flo-Torq III 40-60 HP FourStroke Bigfoot 90-115 HP FourStroke (Aluminum or Stainless steel props, reduces prop rattle)

posted 09-15-2004 01:06 AM ET (US)            

Moe, the part number you've quoted is the same as the part number given me by Canadian customer service. I've followed your links and that sure looks like it will do the trick.

I will follow up the whistle next summer. The gasket leak sounds like as good a place to start as any. The only other suggestion I've heard is the fuel pump.

Thanks again

posted 09-15-2004 09:28 AM ET (US)            

The hub certainly may cure the rattle while the motor is engaged in gear, but I don't see how a different hub or style prop will cure a gear engagement problem.

A properly adjusted shift cable should engage the boat in gear at idle rpms before the throttle cable increases motor rpms.

Rich

posted 09-15-2004 10:49 AM ET (US)         

It remains to be seen whether sailing, much less trailer sailing, is for us. It's going to take twice as long at the ramp, stepping and unstepping the mast, and once on the water, hoisting the sails, etc. If we have to do that every time, we may use it less. On the other hand, if we put it in a slip, we may use it a lot more. I think it's worth trying though.

So I'll still be around CW, at least in the immediate future, trying to help the growing number of 150 Sport owners.

posted 09-16-2004 04:22 PM ET (US)            

I will also say I'm glad Moe is keeping his 150. I have read a number of your posts and looked at a number of your diagrams on your layout and floorplan comparisons. I admire your thoroughness.

posted 09-16-2004 09:03 PM ET (US)            

The plastic hub part is about $12. The whole hub kit is about $40. I don't know how many people with these Flo-Torq hubs are carrying around a spare plastic insert, but my guess is not all that many.

In comparison, making the propeller as a universal item and fitting it to different engine brands and models by method of a hub/adapter has quite a bit of advantage for the manufacturer. They can make one propeller and fit Mercury, OMC, Yamaha, and Honda. This has to save them manufacturing and inventory costs. It seems like an excellent idea from a manufacturing point of view.

The downside for the customer with the Flo-Torq hub style propeller is precisely what we are hearing here: they CLUNK into gear, maybe even rattle a bit. These hubs definitely make more of a CLUNK when shifting than the classic, traditional, outboard propeller configuration using a rubber coupling between the propeller hub and the propeller shaft. The rubber not only provided a break-away protection device in the event of a hard propeller strike against an underwater object, but it also seems to provide some cushion to the shifting. Just as reported here, without the rubber hub the shifts can be noisy.

If you think the shifts are noisy and make a clunk on a little 60-HP propeller, wait until you try a big, heavy, 4-blade stainless steel propeller designed for 200-HP and more. They really CLUNK!

The fact that there apparently is a different style of Flo-Torq hub which includes some rubber coupling is a good indication that Mercury is aware of this problem.

posted 09-17-2004 01:31 PM ET (US)         

The 150 Sport originally came with the cushy hubbed aluminum 15" Black Max prop. It's a good prop for this boat with a light load and no drag from a bimini, putting max rpms at the lower end of the 5,500-6,000 rpm WOT operating range. However, with the bimini deployed, and a load of 3 people or more, and their gear, the maximum rpm can drop to 5,400 rpm, or less. With me and Barb, and our gear, and the bimini deployed, the maximum rpm varies with the location of the 50-60 lb cooler. With it in the stern area, the maximum rpm is 5,400 rpm with a top speed of almost 34 mph. The motor is trimmed up slightly past perpendicular to the water surface. However, with the cooler tied down just behind the bow locker, the maximum rpm is only 5,200 rpm with a speed just under 32 mph, and the motor has to be trimmed way up past perpendicular to the water surface to get max rpm and speed.

Yes, with the cooler forward, the boat is too bow-heavy at that speed, and the motor has to be trimmed up to try to lift the bow and get more of the bottom out of the water. But most of our running is at lower speed, especially in heavy seas, and the cooler forward helps the bow cut through the waves rather than launch off them, not to mention lowers planing speed, both of which would otherwise require trimming the motor down past perpendicular with the water surface. We balance the boat for the lower speed we operate at, rather than for maximum speed.

The next size down in the Black Max line is the 13" pitch. With the above configuration, including cooler forward, the maximum rpm jumps from 5,200 rpm to 6,000 rpm at the same just under 32 mph top speed. I haven't tried the 13" prop with the cooler in the stern area, but I suspect the max rpm would be close to the 6,250 rpm rev limit. This is a huge difference in max rpm, roughly twice the 200 rpm per inch of pitch rule of thumb.

Given that it takes about 3 minutes to change the prop, we can have a smooth-water, lower rpm cruising configuration with the 15" prop and cooler aft (even though it's slightly below the max rpm range at WOT), or a heavy-water (or tubing/skiing) configuration with the 13" prop and cooler forward. However, most owners want a one size fits all single prop, and the 13" is WAY too little pitch for a lightly loaded 150.

Hence, the 14" Vengeance, an uncupped, almost identical profile of the aluminum Black Max props, is Whaler's only choice. Clearly a cushy hubbed prop, either a 14" Black Max or a special fixed hub version of the stainless Vengeance, would be optimum, but such aren't available.

I agree the noise problem is the added mass and intertia, not only of the larger prop even with aluminum, but especially of the denser stainless, compared with the low mass and inertia, and torque, of the small flywheel and small displacement motor. This MAY be compounded with greater lash in the 2.33:1 gearing that MIGHT not be as great on the 1.87:1 small foot.

posted 09-17-2004 10:42 PM ET (US)            

Seems like the answer is to add a 15" black max as our use is almost always lightly loaded, rarely WOT, and a quiet boat for fishing.

The vengeance can come out for tubing days with a crowd.

posted 09-18-2004 06:32 AM ET (US)         

Perhaps someone here has a 16" Vengeance you can try.

posted 09-20-2004 08:50 PM ET (US)         

Only Boston Whaler's engineers know the actual reason why the smaller Whalers come with BigFoots, wherever possible. The only instance I recall where this isn't the case is on the 130 Sport, where its 40HP 4-cycle is a lighter, 750cc 3-cylinder "smallfoot." The 40HP BigFoot is the same 1000cc 4-cylinder as the 50 and 60HP BigFoots, and the 130 couldn't carry its weight. I have to believe Whaler's engineers know what they're doing, that they actually do test their boat designs with different motors, and that they've found the BigFoots to perform better.

To my knowledge, they haven't shared this reason with anyone on this forum, so I can only surmise that while the BigFoot's wider lower end and larger diameter prop may provide more drag, its lower gear ratio (2.33:1 vs 1.83:1) and larger diameter, greater pitch prop probably more than offset the drag at the 35 mph or so maximum speed 60HP can push this boat regardless of what prop is on it.

posted 06-29-2009 06:39 PM ET (US)            

Your original prop is equipped with a Flo-Torq II. See your ENGINE owners manual in the changing prop section. Take yours off and look and all will make sense (it's good to learn to do this anyway). Order a III kit and install it. It's worth it unless you can get one for free after the Deal!

DO NOT TORQUE THE III KIT TO 150LB! There is some mention on this board to do that but that spec is for a different kit. Read the correct section of the kit instruction sheet and compare that with the illustration in your engine owners manual. Don't hurry...make sure you are reading the correct section for your engine.

I also noted with the 14 inch Vengeance, top engine RPM's were substantially over 6k trimmed and just me at 200lb, a full fuel tank and normal items like anchor etc. Because I wanted to reduce WOT RPM's and needed a spare prop, I picked up a Black Max 15 inch. Still just pegs the tack at 6k trimmed out but a safer WOT in my opinion.

Note that the Specs on the BW Web Site for the 2009's use a 15 inch Vengeance, I bet to bring the RPM's down a bit. The engine protection system never did activate while I was screaming down the lake but I'm sure it was close. I also gained a bit of top end with the Max 15inch. It may be more prone to cavitation during sharp high speed turn etc but haven't fully tested or seen that yet.

One responder to a previous post suggested the 16 inch Vengeance. I think that would be a great choice if the load is always just me and/or I didn't mind changing props for different applications. For now, if I spend any more money on props I will likely spring for the Vengeance 15 as it might be the best one for overall general use and produce an acceptable WOT RPMs with light loads. The Flo-Torq III kit can also be transferred to any of these props as needed.

posted 07-18-2011 11:03 AM ET (US)            

The Flow Torq II kit sometimes has a little rattle at ultra low RPM though...but adding a bit of throttle for an extra 100-200RPM will smooth everything out.

With 6200RPM on your 14pitch Stainless prop, you should be able to go up one more pitch = max speed and fuel efficiency!