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Prop and rpm


General disarray

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Hey guys,

was talking to powertech today and it sounds like I am not seeing the Rpms I should on my vmax hpdi so I wanted to see what you guys are seeing and what could be the issues....maybe filters?

 

03 22v with 04 200 vmax hpdi

powertech 3 blade 21p

Loaded I am seeing 48-50 on the speedo turning 4900 Rpm tapped out

i may not have really pushed it so I'm going to run it hard to see what my Max's are next weekend 

 

 

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One of the problems that are frequently seen when people are trying to find the right prop and relay accurate information to someone like Ken at Prop Gods or PowerTech is that you have to determine your actual wide open throttle rpm and speed. To get that number you need to trim the motor to the highest point before it starts to blow out or start cavitation/ventilation.  On a Pathfinder that also requires setting your jack plate to the proper height if you have one.   

Max RPM numbers on a trimmed down or buried motor are meaningless.   If you want the best advise on props, get accurate rpm/speed to plane,  cruise rpm/speed and true WOT rpm/speed. Of course, loading information is also important.

General, I recommend you go out and run the boat again with this in mind then call the prop guys back again. 

 

Here is a fairly good article on point.

http://www.boats.com/reviews/outboard-expert-the-right-propeller/#.WhAlT7hOmhA

 

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11 hours ago, General disarray said:

Hey guys,

was talking to powertech today and it sounds like I am not seeing the Rpms I should on my vmax hpdi so I wanted to see what you guys are seeing and what could be the issues....maybe filters?

 

03 22v with 04 200 vmax hpdi

powertech 3 blade 21p

Loaded I am seeing 48-50 on the speedo turning 4900 Rpm tapped out

i may not have really pushed it so I'm going to run it hard to see what my Max's are next weekend 

 

 

brother had same setup, same numbers. within the limit range but would have liked to seen 5200.  range is 4500-5500 if not mistaken.

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2 hours ago, billablehours said:

One of the problems that are frequently seen when people are trying to find the right prop and relay accurate information to someone like Ken at Prop Gods or PowerTech is that you have to determine your actual wide open throttle rpm and speed. To get that number you need to trim the motor to the highest point before it starts to blow out or start cavitation/ventilation.  On a Pathfinder that also requires setting your jack plate to the proper height if you have one.   

Max RPM numbers on a trimmed down or buried motor are meaningless.   If you want the best advise on props, get accurate rpm/speed to plane,  cruise rpm/speed and true WOT rpm/speed. Of course, loading information is also important.

General, I recommend you go out and run the boat again with this in mind then call the prop guys back again. 

 

Here is a fairly good article on point.

http://www.boats.com/reviews/outboard-expert-the-right-propeller/#.WhAlT7hOmhA

 

Thanks for the info. This is my plan next weekend. I don't think I've trimmed it till blow out so just might not have pushed it hard enough yet. Was interested to see what others were seeing

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6 hours ago, General disarray said:

Manual states 5-6k operating max power at 5500 Powertech said the 200 should have enough to spin a 21 at 55k

If your motor manual lists 6000 as max RPM, you should run a prop that will reach 6000 RPM (tabs up, motor trimmed up highest, aired out) with one person and a light load (standard capacity fuel tank full).  This will get you the best all-around performance for that model prop - power/hole shot, best fuel economy, top speed.  Your motor will not have to work as hard and will last longer too.

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7 hours ago, geeviam said:

If your motor manual lists 6000 as max RPM, you should run a prop that will reach 6000 RPM (tabs up, motor trimmed up highest, aired out) with one person and a light load (standard capacity fuel tank full).  This will get you the best all-around performance for that model prop - power/hole shot, best fuel economy, top speed.  Your motor will not have to work as hard and will last longer too.

I more or less agree. Actually, the 5 to 6 k rpms is the WOT range the motor should be in order to keep valve train loads at design standards. Your manual will also state the motor rating and will be like XXX HP @ XXXX RPM. On my F250, its a 5 to 6 k operating range and 250 HP @ 5500 rpm. That’s the peak of the HP curve and max output. Any prop at WOT in the stated range should not be detrimental to the motor, and/or the longevity of the motor.

Be careful about max rpm. You don’t need a prop that hits the max, although you may want to. Modern motors have rev limiters which prevent an over speed condition.  They are usually set at about 5 per cent above max. A heavy boat will want to be closer tho the max, requiring a flatter pitch. If the pitch is too flat you will hit the max, and the rev limiter will stop the acceleration to avoid over speed. With out the limiter, you could go to 7 k rpm,  which is not good for the motor ( outside valve train load limits)

 

Modern motors and props are not the same as the 80s and 90s. Props are all progressively pitched with each prop manufacturer now having their own prop geometries. Pick out a prop manufacturer or prop shop that has a lot of experience on your boat and motor combination. They will give you the performance you want. Their experience is valuable. For instance, Pathfinders tend to like larger diameters, and large blade areas. Most( but not all) owners really like the Four blade props. Every boat motor combination is different. A proptech 15x21 will deliver slightly different performance than a Merc or Yamaha of the same size and diameter.

I tend not to do what others are doing, rather make the boat do what I want it to do, staying inside the OEMs design criteria, sticking with a prop manufacturer. And I owned a  prop shop for 20 years.

Hope this helps

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5 minutes ago, FROZEN said:

I more or less agree. Actually, the 5 to 6 k rpms is the WOT range the motor should be in order to keep valve train loads at design standards. Your manual will also state the motor rating and will be like XXX HP @ XXXX RPM. On my F250, its a 5 to 6 k operating range and 250 HP @ 5500 rpm. That’s the peak of the HP curve and max output. Any prop at WOT in the stated range should not be detrimental to the motor, and/or the longevity of the motor.

Be careful about max rpm. You don’t need a prop that hits the max, although you may want to. Modern motors have rev limiters which prevent an over speed condition.  They are usually set at about 5 per cent above max. A heavy boat will want to be closer tho the max, requiring a flatter pitch. If the pitch is too flat you will hit the max, and the rev limiter will stop the acceleration to avoid over speed. With out the limiter, you could go to 7 k rpm,  which is not good for the motor ( outside valve train load limits)

 

Modern motors and props are not the same as the 80s and 90s. Props are all progressively pitched with each prop manufacturer now having their own prop geometries. Pick out a prop manufacturer or prop shop that has a lot of experience on your boat and motor combination. They will give you the performance you want. Their experience is valuable. For instance, Pathfinders tend to like larger diameters, and large blade areas. Most( but not all) owners really like the Four blade props. Every boat motor combination is different. A proptech 15x21 will deliver slightly different performance than a Merc or Yamaha of the same size and diameter.

I tend not to do what others are doing, rather make the boat do what I want it to do, staying inside the OEMs design criteria, sticking with a prop manufacturer. And I owned a  prop shop for 20 years.

Hope this helps

Definitely does and it seems like powertech does have a lot of experience with the pathfinder line. For my 200 manual states 200 hp @ 5500 . I'm turning probably 5k at 50mph with a 3 blade 14" 21p

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1 hour ago, General disarray said:

Definitely does and it seems like powertech does have a lot of experience with the pathfinder line. For my 200 manual states 200 hp @ 5500 . I'm turning probably 5k at 50mph with a 3 blade 14" 21p

Seems you need a lower pitch, and possibly a larger diameter if 5000 is WOT. 

I assume you are talking to Josh or Marcus there. They will do their best to specify a prop and trust them. They will do you right.

I’m going through the same process. I “had”a Powertech 3 blade that I sent to a prop shop for inspection. They reconditioned it, and, in the process, changed the rake. I lost 900 rpm. I sent it to Proptech and they said they could NOT fix it. SCRAP!

So, they have specified a 4 blade for me , and pointed me toward a few of their dealers that have an exchange program, sort of pay for the prop, try it once, and if wrong, they will swap it out for the “right” one. As long as they can sell it as new to someone else. Fair deal.

These modern props are like Swiss watches. When they work, they are fantastic, but bend a blade........ They are not easy to fix either.

Anyone ever repaired your PT prop? That may be another problem. Look for Prop shop numbers stamped on the barrel. Your prop might have been the perfect prop for your boat in a new and clean condition. If repaired, it might have less cup, cup positioned wrong, not a 21 pitch anymore, diameter and rake off, etc. If you have no idea if it ever visited a prop shop, bite the bullet and start over.

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9 minutes ago, FROZEN said:

Seems you need a lower pitch, and possibly a larger diameter if 5000 is WOT. 

I assume you are talking to Josh or Marcus there. They will do their best to specify a prop and trust them. They will do you right.

I’m going through the same process. I “had”a Powertech 3 blade that I sent to a prop shop for inspection. They reconditioned it, and, in the process, changed the rake. I lost 900 rpm. I sent it to Proptech and they said they could NOT fix it. SCRAP!

So, they have specified a 4 blade for me , and pointed me toward a few of their dealers that have an exchange program, sort of pay for the prop, try it once, and if wrong, they will swap it out for the “right” one. As long as they can sell it as new to someone else. Fair deal.

These modern props are like Swiss watches. When they work, they are fantastic, but bend a blade........,

Marcus. you are spot on. 

 

Problem is he said I should be seeing higher rpm with what I have (5500ish) unless he's mistaken 

wonder if maybe mine has been reconditioned and same issue?

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Sorry, you’re quick. I edited my response while you were replying.

20 minutes ago, FROZEN said:

Seems you need a lower pitch, and possibly a larger diameter if 5000 is WOT. 

I assume you are talking to Josh or Marcus there. They will do their best to specify a prop and trust them. They will do you right.

I’m going through the same process. I “had”a Powertech 3 blade that I sent to a prop shop for inspection. They reconditioned it, and, in the process, changed the rake. I lost 900 rpm. I sent it to Proptech and they said they could NOT fix it. SCRAP!

So, they have specified a 4 blade for me , and pointed me toward a few of their dealers that have an exchange program, sort of pay for the prop, try it once, and if wrong, they will swap it out for the “right” one. As long as they can sell it as new to someone else. Fair deal.

These modern props are like Swiss watches. When they work, they are fantastic, but bend a blade........ They are not easy to fix either.

Anyone ever repaired your PT prop? That may be another problem. Look for Prop shop numbers stamped on the barrel. Your prop might have been the perfect prop for your boat in a new and clean condition. If repaired, it might have less cup, cup positioned wrong, not a 21 pitch anymore, diameter and rake off, etc. If you have no idea if it ever visited a prop shop, bite the bullet and start over.

 

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21 hours ago, General disarray said:

Yeah the powertech guy was surprised and said it should be able to push that 21. But the engine seems perfectly smooth so I was interested to hear what others have seen and I'll test as well

I ran a 19 P 3 blade on my 2200 with SHO 225. I could turn 5900 rpms. There's no way a 200 is going to turn a 21 that fast on the same boat. 

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Frozen, thanks for your insight.  There is no substitute for your 20 years of hands-on knowledge from owning a prop shop.  Like you said, every boat motor combination is different.  I can only offer advice on what has worked best for me, based on my own experiences.

Unlike a moving automobile, a powerboat is essentially always running uphill, without the ability to downshift for a lower gear and more RPM.  The max RPM range on my Yamaha VF115 SHO is 5300 - 6300, with a rating of 115 HP @ 5500 RPM.  The rev limiter definitely kicks in at 6400 RPM.  I have tried so many props on this setup, that I have to look at my notes to remember them all.  On my rig, the props that ran in the 5700 to 6100 RPM WOT range were ok at high speed with a light payload, but slower to get on plane or carry a heavier payload.  When I tried a couple of props that ran 6200 to 6300 RPM WOT, the difference in all-around performance was noticeably better.  Throttle response, acceleration and hole-shot were much improved.  In other words, the motor was having an easier time running uphill.

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43 minutes ago, Tall Tails said:

I ran a 19 P 3 blade on my 2200 with SHO 225. I could turn 5900 rpms. There's no way a 200 is going to turn a 21 that fast on the same boat. 

This is exactly why I was asking. I have no frame of reference but the motor seems to run solid and smooth so I can't imagine its losing power at the head.

 

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I have a 2007 2200 V with a 225 SHO.  I am running a Powertech OFX3 x 19 pitch.  Fishing with 3 old, fat guys and everybody's tackle yesterday,  I could still hit 5700 rpm's and 53 mph trimmed out.  With just me, 5900 rpm's and 57 mph is no problem.

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11 hours ago, General disarray said:

Definitely does and it seems like powertech does have a lot of experience with the pathfinder line. For my 200 manual states 200 hp @ 5500 . I'm turning probably 5k at 50mph with a 3 blade 14" 21p

 

10 hours ago, General disarray said:

Marcus. you are spot on. 

 

Problem is he said I should be seeing higher rpm with what I have (5500ish) unless he's mistaken

wonder if maybe mine has been reconditioned and same issue?

 

8 hours ago, General disarray said:

Thanks I'm leaning that way. Here's the only markings on the prop 

IMG_4942.JPG

IMG_4944.JPG

If those are the only markings on the barrel, then, likely, it’s never been to a shop. For defensive purposes, job numbers are usually stamped. Four or five digits.

If you are starting over, then send the prop to Josh/Marcus and ask them to send it through the shop, and tell you what you got, good or bad. If good shape, PT will likely steer you to to check the motor and especially the tach. Have the tech check the tach for accuracy against a handheld. Tachs do go bad and they need to know how many cylinders to “read”. Usually easy fix.

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8 hours ago, geeviam said:

Frozen, thanks for your insight.  There is no substitute for your 20 years of hands-on knowledge from owning a prop shop.  Like you said, every boat motor combination is different.  I can only offer advice on what has worked best for me, based on my own experiences.

Unlike a moving automobile, a powerboat is essentially always running uphill, without the ability to downshift for a lower gear and more RPM.  The max RPM range on my Yamaha VF115 SHO is 5300 - 6300, with a rating of 115 HP @ 5500 RPM.  The rev limiter definitely kicks in at 6400 RPM.  I have tried so many props on this setup, that I have to look at my notes to remember them all.  On my rig, the props that ran in the 5700 to 6100 RPM WOT range were ok at high speed with a light payload, but slower to get on plane or carry a heavier payload.  When I tried a couple of props that ran 6200 to 6300 RPM WOT, the difference in all-around performance was noticeably better.  Throttle response, acceleration and hole-shot were much improved.  In other words, the motor was having an easier time running uphill.

Geeviam,

You are a wise man! IMO, you did everything right. You’re within specs and you have a prop that makes the boat do what you want. 

Back in the day, I supplied props to a medium sized boatbuilder in NE Fl. Engineering was having a hard time getting a brand new model  to perform. Engineering said the boat weighed 15,200 lbs. Marketing advertised it as a 15,000 lb boat. lb boat. Engines were sized for a 15,000 lb boat. When  difficulties arose on one boat, and after three sets of trial props, they weighed it in the travel lift and found the boat weighed about 16,500 lbs. They had me reduce the pitch 2 inches on the delivery props, and gave it to the new owner. Six months later, the owner brought me his props and said he couldn’t make WOT and told me about CAT and the boatbuilder spent the last three days trying to “tune” the engines. 

I told him that we couldn’t remove any more pitch because 2” is the max from originally casted. (Thank goodness for stamping job numbers on props!). I told him to haul the boat and weigh it. He did, and found the boat now came in at a shade less than 18,000lbs. A lot of fishing gear, TVs, booze in the lockers, etc. Bought a new set of props with 4 less inches of pitch than was delivered, and he was happy.

Happens more than you would think.

 

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13 hours ago, FROZEN said:

 

 

If those are the only markings on the barrel, then, likely, it’s never been to a shop. For defensive purposes, job numbers are usually stamped. Four or five digits.

If you are starting over, then send the prop to Josh/Marcus and ask them to send it through the shop, and tell you what you got, good or bad. If good shape, PT will likely steer you to to check the motor and especially the tach. Have the tech check the tach for accuracy against a handheld. Tachs do go bad and they need to know how many cylinders to “read”. Usually easy fix.

Awesome thanks for the info! It's going in first week of Jan for the service so timing will be perfect 

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Took her out and ran her today - loaded though.

 

had 3 people 2 coolers ready to fish, trolling batteries in, trolling motor, and a decent wind.

started blowing out around 5000ish and was getting 40-41 on the speedo and gps. I attribute the speed reduction to the weight as the rpm range is on par with what I thought I was getting at 50-51 mph I have seen before

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I may have missed if you have a jack plate. This is my first boat with a jackplate. My first few outings I was raising my jackplate  too high and then trimming. Rpm were high but speed was low.  I still think your asking a lot of your motor in real world conditions such as people and gear on your boat. Of corse I could be completely wrong :) 

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