Mercury Demand, Demand Linear, Demand Guardian

[alldodge]

Going to discuss prop selection using Mercury scanner with new Verado 250hp OB with DTS
Props - Merc Rev 4 19 pitch

Hey @muc help keep me straight

Thought about putting this in the prop section but this is about how to determine which prop should be used based on Merc data.

I'm using the Techmate Pro and would be easier using Diacom, but it is what it is

First run today Saturday Labor day weekend, note: best not to do this on holiday weekend.
Was watching Demand Linear (DL) and Demand Guardian (DG), and that was first mistake. I should also have watched "Demand".

Watching DL I see the TPS is at 100% so the throttle is at WOT. Trimming up or down in real choppy water is not giving me a good indication that full power is being applied to the prop. Seeing DG is at 0% so guardian appears to be not in play

Max RPM is in the 5800 range, even when I trim up above what should IMO be max. So is there another guardian issue not showing on the Techmate or something else. Need to test more and watch Demand

 

[Fun Times]

Hey AD, have you had a chance to see documentation from Merc regarding adaptive speed control propping starting on page 4 of 11,

https://holesbaymarine.co.uk/catalog/media/F53DEL3GOJSW4Y3INVQXE2LOMUXW2ZLENFQS6YTNMUXUOQKZIRBVQQSRI5JE6RCFJVBFER2SJ5CUWVCTG5DUCMSRFZYGIZQ

Mercury Break in/ G3 Diagnostic Demand Linear

Serial Number # 3B102791 13x24 1:85:1 24P Tempest Plus Recently received my Triton 18 TRX with 200hp Mercury ProXS. Passed the 2 hour break in and when I try to run open throttle for 1 min I am only getting to 4300 rpms and 50mph. Do I need to get past the 10 hour break in to have it...

www.bbcboards.net

 

[cyclops222]

I just watch the tachometer and the GPS speed numbers. Tells me instantly. How fast any changing drive angle is producing.

 

[alldodge]

Hey AD, have you had a chance to see documentation from Merc regarding adaptive speed control propping starting on page 4 of 11,

https://holesbaymarine.co.uk/catalog/media/F53DEL3GOJSW4Y3INVQXE2LOMUXW2ZLENFQS6YTNMUXUOQKZIRBVQQSRI5JE6RCFJVBFER2SJ5CUWVCTG5DUCMSRFZYGIZQ

Mercury Break in/ G3 Diagnostic Demand Linear

Serial Number # 3B102791 13x24 1:85:1 24P Tempest Plus Recently received my Triton 18 TRX with 200hp Mercury ProXS. Passed the 2 hour break in and when I try to run open throttle for 1 min I am only getting to 4300 rpms and 50mph. Do I need to get past the 10 hour break in to have it...

www.bbcboards.net

Have not but will have a look

I just watch the tachometer and the GPS speed numbers. Tells me instantly. How fast any changing drive angle is producing.

Which only means you have no idea what the topic is.

 

[cyclops222]

 

[tpenfield]

Following this thread with great interest. Does this apply to I/O engines? I rarely trim up, because at my typical cruising speed (27-30 mph), the boat tends to slow down with any more than the slightest amount of upward trim.

With any amount of waves, which is normal for my area, all bets are off as far as trimming the boat.

 

[Pmt133]

Hey AD, have you had a chance to see documentation from Merc regarding adaptive speed control propping starting on page 4 of 11,

https://holesbaymarine.co.uk/catalog/media/F53DEL3GOJSW4Y3INVQXE2LOMUXW2ZLENFQS6YTNMUXUOQKZIRBVQQSRI5JE6RCFJVBFER2SJ5CUWVCTG5DUCMSRFZYGIZQ

Mercury Break in/ G3 Diagnostic Demand Linear

Serial Number # 3B102791 13x24 1:85:1 24P Tempest Plus Recently received my Triton 18 TRX with 200hp Mercury ProXS. Passed the 2 hour break in and when I try to run open throttle for 1 min I am only getting to 4300 rpms and 50mph. Do I need to get past the 10 hour break in to have it...

www.bbcboards.net

That's actually really cool and surprisingly straight forward.

 

[alldodge]

Following this thread with great interest. Does this apply to I/O engines?

It can apply to I/O's but they have to have Adaptive Speed Control. Look at the link FT posted

 

[alldodge]

Motors have performance exhaust and Merc says it has no effect on performance, well that is not entirely true at least in my case

Smooth water and no one around, love it
Performance exhaust closed
Demand = 100%
DL = 100%
RPM = 5850
MPH = 54
Manual trim

Performance exhaust open
Demand = 95%
DL = 100%
RPM = 6000
MPH = 56
Auto Trim

So with exhaust open and at WOT the ECM reduces power at Rev limit. In both cases the motor RPM was above 5200 so I need more pitch. I have a pair of Mirage plus 21P that I'll try next. May not get to changing until next year but who knows

 

[nola mike]

Motors have performance exhaust and Merc says it has no effect on performance, well that is not entirely true at least in my case

Smooth water and no one around, love it
Performance exhaust closed
Demand = 100%
DL = 100%
RPM = 5850
MPH = 54
Manual trim

Performance exhaust open
Demand = 95%
DL = 100%
RPM = 6000
MPH = 56
Auto Trim

So with exhaust open and at WOT the ECM reduces power at Rev limit. In both cases the motor RPM was above 5200 so I need more pitch. I have a pair of Mirage plus 21P that I'll try next. May not get to changing until next year but who knows

In that situation, is DL with guardian 95% as well (2nd scenario)? How do auto and manual trim factor in?

 

[alldodge]

In that situation, is DL with guardian 95% as well (2nd scenario)? How do auto and manual trim factor in?

Don't know if DL was at 95% because I forgot to show the Admiral for to scan the Techmate to see it.

Don't see a difference just something to note for next time out. In most cases if I leave it on auto and get above 4500 RPM the boat starts to porpoise, so I take over. This time it didn't going back but I went from slow cruiser to WOT and noticed it wasn't porpoising with exhaust open

 

[muc]

The S.B. @Fun Times posted is good for your engines (as far as propping ASC) it’s nice because it gives examples that the install manual for your engine doesn’t But on page 35 of the installation manual there is a nice and easy to use chart.

Yes, you need to make sure Demand Linear (DL) and Demand Guardian (DG) are both at 100% before you look at demand.

Demand Linear with Guardian will always be the same as Demand Linear unless the motor is in Guardian for one of these reasons.

The Engine Guardian System will reduce power in the event of:

• Engine coolant temperature overheating

• Low oil pressure

• Low sea pump pressure

• Overspeed

• Battery voltage high/low

• All DTS critical faults

Also, anytime the motor goes into Guardian --- the warning horn will sound and notification will show in SmartCraft. With your motors, about the only way to go into overspeed is to be grossly under propped or wave jumping.

From what I understand, Active Trim is really only useful at cruising speeds. When you run wide open you will probably need to take control. Have you played with the Major Trim Profile Curves? Remember you have a “one off” boat. So dialing in stuff like this is something that would be best for you to do. It’s good to see you checking propping, I’m pretty sure Chap didn’t and most dealers nowadays just do a quick check.

From the numbers you have posted so far, looks like you’re probably propped about right. But the right props can make a big difference! But it can get expensive.

I’ve had too many customers with too much money. Some wanted top speed, some good midrange, some wanted to carry the bow at low planning speeds. But one of my best stories was a guy who bought a Scarab back in the Miami Vice days. Special order with big motors. Another tech rigged and delivered. Next day it was back, customer couldn’t get it on plane. Service manager sent me to test drive it and sent customer to get calmed down by the Marina president. I was able to get it on plane and to WOT, but had to use tabs and feather the throttles because the props would blow out. I get back to the dock and Pres and customer waiting. Too much horsepower for these props. Pres says he will order new wheels and everybody will be happy. Few days go by and I get sent to his office, gives me a couple of boxes and says to install them but DON’T DROP THEM. I do the swap and as I’m lowering the boat into the water he comes out and says “warm it up, get out past the minimum wake and slam the throttles wide open” I do as I’m told. The engines jump to 4000 RPMs and the boat just shakes and starts slowly moving. As it gets up on plane the RPMs drop a little and it feels like I was shot out of a slingshot. Picked up 7 MPH over the last run and the boat feels light as a feather up on plane. Pres is waiting at the dock when I get back. “what do you think?” I’m holy cow what a difference! He says “yup that’s what 20 grand will do, if you want to play – you have to pay”.

Moral of the story. Some of the times I spent a lot of customers money, they were happy like the Scarab guy. But every once in a while the props from the factory were pretty good.



@tpenfield yes you have this software in your engines also.

 

[alldodge]

Back out yesterday with a head wind, and D and DL are both at 100% around 5950 rpm. Guardian stayed at none on Techmate

The dealer who set the auto trim up did a pretty good job at slow cruiser and WOT, not so much at a bit faster cruise. During WOT run I took over and trimming in either direction would reduce speed. I do want to try the reset procedure and reprogram trim to get the faster cruise (between 35 to 40 mph) adjusted better

The boat has always jumped on plane
Using the chart it's saying to increase prop pitch

Muc Sounds like that boat needed some vent tubes on the plates to get the props spinning

 

[Scott06]

During WOT run I took over and trimming in either direction would reduce speed. I do want to try the reset procedure and reprogram trim to get the faster cruise (between 35 to 40 mph) adjusted better

That is pretty impressive. Does it alter the trim based on conditions that day or what it was set to for WOT?

 

[alldodge]

That is pretty impressive. Does it alter the trim based on conditions that day or what it was set to for WOT?

My understanding
Auto trim has 5 settings. Manual says to setup using 3 for normal cruise. As speed is decreased trim is adjusted. Then down button which selects 2 and so on to 1 as speed slows. Same goes with 4 and 5, which 5 being close to or at WOT.