Mercury Props.-

[Sea Rider]

A friend of mine has a 4 stroke Merc 60 HP motor which is revving at 5000 K wot revs lightly loaded, would like to go for a prop maximization to pull wot revs towards max 6K revs according to factory specs. Is a Quicksilver black diamond prop the OEM prop that Merc delivers with motors ? The current 3 blade prop is a 11 pitch, for motor to rev at 6 K will need a 3 blade 9 pitch minimum ?

Happy Boating

 

[WesNewell]

Must be a pretty heavy boat if he only gets 5000 rpms with an 11p prop. It would help to know the type boat and dry weight of it. And also where the av plate is in relation the the hull bottom. I have no idea what if any prop merc delivers with there engines. My guess would be none, since the needed prop will vary a lot depending on use. If they do deliver a prop with the engine, pitch should be specified at time of order.
The 12p spitfire 4 blade prop that came with mine would do 6000 rpm on my 995# boat with normal load, even though the engine was mounted too low.

 

[Sea Rider]

Nope, its a 470 meter hard hull Zodiac. This motor was bought with an installed prop. It's only 500 wot revs from its min wot rpm range. Engine/transom has a spot on height match. Could go for a Solas or other brand prop, but would prefer to stick and play with OEM Merc props.

Happy Boating

 

[Faztbullet]

Merc motors over 30HP don't not come with props from factory...is it a bigfoot???

 

[WesNewell]

Nope, its a 470 meter hard hull Zodiac. This motor was bought with an installed prop. It's only 500 wot revs from its min wot rpm range. Engine/transom has a spot on height match. Could go for a Solas or other brand prop, but would prefer to stick and play with OEM Merc props.

Find the boat here and post it as I'm pretty sure it isn't 470 meters. And post a picture of the engine mounting. Sorry, i don't trust your judgement of what's spot on.
http://boatspecs.iboats.com/Zodiac_of_North_America/bp/20br2076
Or just tell him to use the Mercury prop selector. If he puts the info in right, he'll a good starting selection.

 

[Sea Rider]

Down here the Merc dealer sells many motors with a installed prop which is usually a medium pitched one. Have not seen any motor with a prop factory delivered that over revved bady, usually all running towards the min lugging side or best scenario around the middle wot rpm range factory stated while running lightly loaded.

Nope its not a big foot, it's the standard 60 HP model with a standard 3 blade black painted alum prop. We both have different motor/transom height working parameters, so it's useless to start a discussion here. Owner says that the motor feels sluggish to plane even though has a installed doel fin.

This motor will undergo a full maintenence in some days, then will go for a wot run at a close rowing water course and visually check waht's going on at back transom, then will know if the motor sits right or not. After that will install a less pitch prop.. Transpom Optimization along a Prop Maximization renders marvell's, that's if you want to get the max out of any motor.

In this case a prop selector is useless, the motor has already an installed prop. Prop selectors are only good if you don't count with a starter prop...

Happy Boating

 

[Faztbullet]

The dealer is installing the prop as the motor from factory is not supplied..

 

[Sea Rider]

The dealer is installing the prop as the motor from factory is not supplied..

The dealer runs a small store that sells general marine equipment including Merc motors, the owner doesn't know where he stands regarding props, he just sells motors with a prop.. Anyway, it's a starter prop and definitely not suited for this precise application...

Happy Boating

 

[WesNewell]

IF you enter the proper values into the Mercury prop selector it will give you the proper pitch you need for the best performance. That is IF you have the engine (it's not a motor btw) mounted at the right height and it is in good running condition. After extensive test, using 12-15p props, I run a 14p ss solas prop and can a max smooth riding speed of 38 mph. A 15p had my rpm's below recommended wot rpm's. And this is the prop selectors output for my setup.
[h=3]MY setup[/h]

• Boat type: Bass
• Usage: Overall good performance/450 ft
• Engine Manufacturer:
  Mercury
• Engine Type: Outboard
• Engine Year: 2017
• Number of Engines: One
• Engine Family: FourStroke
• Engine: 60 EFI 4cyl (995cc)
• Drive / Gear Case: 40-50 HP 3cyl 2-S, 50-60 HP 4cyl 4-S, 1.83 Ratio

[h=3]Details[/h]

• Calculated Pitch: 14.18
• Calculated Weight with engine(s): 1,701.30 lbs
• Calculated Engine RPM: 5,750
• Calculated Boat Speed: 38.09 mph

 

[Sea Rider]

Why dump money going for what the Merc prop selector recommends, the one that dials best is a starter prop and this motor, engine, outboard happens to have one already installed, will only need to max from there. Why do you like to compare your combo performance to other, to each one his own motor/prop installation..

Happy Boating

 

[WesNewell]

I use it to get the proper pitch only. I don't use merc props. I found the Solas ss props i bought to be good performers at half the price of the Mercury props. Still, there's no way i could recommend a prop pitch with such little info supplied. Guessing and using what little info I have the needed prop could be anywhere from 8-13p for your friend.

 

[QBhoy]

Hi searider

you and I share the same thoughts around prop optimisation. But in this case, if it’s the boat I think it is...I’d naturally think that a 11p should send that motor and set up to the moon on the rpm gauge. I’d naturally think a 13-15p would be the go to pitch for this.
Is the motor healthy ? Well trimmed with not just engine but weight distribution around the boat ? You know the usual ?
i know of many similar Avon ribs and small fletcher hills running 50/60 mercs with 13 and 15” pitch props to the rpm range.
unless it’s a big foot, it should be able to turn that 11” to the max easily. Only other thing that might stop it is the shaft length being wrong or it has a silly hydro foil fin on the motor ?

 

[Sea Rider]

The issue with this 470 Rib is that the hull is nearly 20 years old, develops a tremendous front hull drag due to its odd shape when on plane at speed. Would say it's worse than a dog when running. Splashes too much water at side of front hull which slows the combo real bad.



Don't understand why you guys are so surprised that a 11 pitch won't perform right, it's a 4 stroke motor which is slow on hole shot compared to same 2 strokes ones, it's the nature of each beast. Worse if not propped right.



The number stamped on prop body indicates being an 11 pitch, right ? The blades are the Mickey Mouse type, round wide ears which intend to keep using but with a lower pitch say a niner.

Some weeks ago made a 20 Km wot race down current at open sea. Both 470 and 450 Ribs runs standard delivered props and both has the same old hull type. My 450 Rib is a much lighter champ, has a state of the art deep V straight hull in comparison. At flag down my Sib took the lead for some kilometers as jumps on plane real fast, soon after both 60's took the lead till the finish line.



If you check closely the difference in distance between both 60's and my 18 is not that big deal, all motors were running full hammer down since flag down. Both 60's runs good around 5 K with 4 up while my motor runs at full 5850 wot revs factory stated with 2 up. A correct prop maximization is the way to go if wanting to get the max HP out of any motor...

Happy Boating

 

[QBhoy]

The issue with this 470 Rib is that the hull is nearly 20 years old, develops a tremendous front hull drag due to its odd shape when on plane at speed. Would say it's worse than a dog when running. Splashes too much water at side of front hull which slows the combo real bad.



Don't understand why you guys are so surprised that a 11 pitch won't perform right, it's a 4 stroke motor which is slow on hole shot compared to same 2 strokes ones, it's the nature of each beast. Worse if not propped right.




The number stamped on prop body indicates being an 11 pitch, right ? The blades are the Mickey Mouse type, round wide ears which intend to keep using but with a lower pitch say a niner.

Some weeks ago made a 20 Km wot race down current at open sea. Both 470 and 450 Ribs runs standard delivered props and both has the same old hull type. My 450 Rib is a much lighter champ, has a state of the art deep V straight hull in comparison. At flag down my Sib took the lead for some kilometers as jumps on plane real fast, soon after both 60's took the lead till the finish line.



If you check closely the difference in distance between both 60's and my 18 is not that big deal, all motors were running full hammer down since flag down. Both 60's runs good around 5 K with 4 up while my motor runs at full 5850 wot revs factory stated with 2 up. A correct prop maximization is the way to go if wanting to get the max HP out of any motor...

Happy Boating

Searider. The problem is in the picture right there. Ask him to try it with that foil fin removed. I’d imagine his problem is greatly influenced by this. This will have a horrible effect on the attitude of the bow on a boat like this. No need for it at all on that set up. I’ll bet money that it performs like a different boat with it off.

 

[Sea Rider]

Nope, owner has removed it with 0 avail including playing with different trim positions. The problem here is a inefficient hull shape with high coefficient of hull drag being powered with an over propped motor for that hull shape. All these Ribs require tad larger HP motors than their imported competitors comparing same size Ribs. Those hulls are heavier clones, copies of an old Italian hull made here at a fiberglass facility.

You'll see that going down in pitch will bump wot revs up much more than as of right now. How much wot rpm will gain isn't known, only a water test as usually loaded will tell...

Have installed many HP motors with delivered props on light to medium light applications and nome of them run near middle wot rpm range factory stated for them, usually towards the lugging rpm side. A proper prop maximization to lower pitches did wonders.

Hapy Boating

 

[Sea Rider]

Called the local Merc dealer, only stocks the 10 pitch Black Diamond prop at $200.00, that's the OEM Merc prop. A 10 pitch will only bump at best less than half wot rpm of what's required, so useless to go for that prop. The 9 one will need to be imported and that can take somewhere 4 to 6 weeks to arrive. Merc stocks Black Diamond props that range from 7 to 17 in pitch, so lots to play with...

Happy Boating

 

[QBhoy]

Called the local Merc dealer, only stocks the 10 pitch Black Diamond prop at $200.00, that's the OEM Merc prop. A 10 pitch will only bump at best less than half wot rpm of what's required, so useless to go for that prop. The 9 one will need to be imported and that can take somewhere 4 to 6 weeks to arrive. Merc stocks Black Diamond props that range from 7 to 17 in pitch, so lots to play with...

Happy Boating

Searider. I honestly think there is another issue here. There is no way in gods green earth, that a 9” pitch is right for that set up.
something else is wrong, way wrong.
that thing should be approaching a 40mph boat. It is a rib and not a sib presumably. I’ve been loads of small ribs and sibs. Something isn’t right. Has the engine had the compression checked ?
hope you get to the bottom of it.

 

[Faztbullet]

I thought you said it was not a Bigfoot????

 

[Sea Rider]

I thought you said it was not a Bigfoot????

If it were a Bigfoot which don't know, will the posted pic say something ? will it be stated being a Bigfoot on the cowl or somewhere ? This motor has low use hours from new, it's used mainly for spearfishing at an island not far away from the club.

Have not had the opportunity to ride on this Rib. Saturday will have a look on what's going on at back transom. The distance between both plates is only 2.5 inches, so the Merc engine installation fully applies.

If you test say 3 same size Ribs with different hull shapes with a 4 strokes Merc 60 HP motor with an 11 prop, all will dial different wot rpm numbers. The most efficient hull will rendered more, the less efficient much less...

Happy Boating

 

[Sea Rider]

Searider. I honestly think there is another issue here. There is no way in gods green earth, that a 9” pitch is right for that set up. something else is wrong, way wrong.that thing should be approaching a 40mph boat. It is a rib and not a sib presumably. Hope you get to the bottom of it.

Thanks QBhoy for your concern, have not said that a 9 pitch is right, only a wot test will determine so, it's just the pitch that would like to try to bump the actual 5 K wot revs to 6 K. This 4.70 meter Rib ain't a small Rib, LOL!!

Happy Boating