500/520 DB official thread

QSM11 - Are you guys getting 100% Load at 100% throttle? Haven’t paid much attention to this over the years but read an article about it today in BoatTest.com. This article said that although it isn’t necessarily bad to not get to 100 Load at 100 Throttle but you may be leaving gains on the table.

I will post my WOT results next time I get out and can confirm. Below is my latest runs but I didn’t have the screen set to show load at WOT. Will change that…

Boat is running reasonably fast and pretty efficient (full of fuel, empty water and holding) but port engine is burning slightly more fuel. Will check the synchronization but I don’t think it’s that. Just had the bottom cleaned and props reset to best pitch for me 32”x 30.8” pitch. I wonder if the port prop has slightly more pitch compared to the starboard prop.


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Highest load - 94% at 2380 RPM at 31MPH if I remember correctly. Props - 28X31
 
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Highest load - 96% at 2380 RPM at 31MPH if I remember correctly. Props - 28X31

Thanks - I corrected my prop size in the original post. Props 28" x 30.8" Are you pretty close between the two motors; GPH, LOAD, etc? Looking back at some of my previous photos I was within a .5 GPH between engines before...

Tom - so adding more pitch you would increase the load at WOT.?. However I understand that we are all trying to reduce load to improve the GPH and reduce exhaust heat at cruise.
 
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Thanks - I corrected my prop size in the original post. Props 28" x 30.8" Are you pretty constant between the two motors; GPH, LOAD, etc? Looking back at some of my previous photos i was within a .5 GPH between engines before...

Tom - so adding more pitch you would increase the load at WOT.?. However I understand that we are all trying to reduce load to improve the GPH and reduce exhaust heat at cruise.
Engines are pretty close and when on Sync spot on RPM wise.
Yes adding pitch increases load, fuel consumption, EGT's, and reduces RPM.
The props on my boat were 28X33 and I had them add a hundred RPM which took them to 28X31. If I did it again I'd go to 28X30.
The interesting thing is I don't think I lost any speed taking pitch out.
Fuel wise at 1800 RPM I'm burning 35 GPH combined and running 23 MPH; that's pretty close to the sweet spot. Then at 2000 RPM, 44 GPH at 28 MPH. So, on the pins the engines are probably hitting the limiters with the max load 94%.
My best economy cruise is 1800 RPM.
 
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I didn’t notice my load at full throttle in the past but now I am curious so I will check it out this spring. Here are my numbers. My fuel burn has always been a little off between the engines.

3E38FA47-BED8-49BA-B616-678BD4DF9252.jpeg
 
Engines are pretty close and when on Sync; spot on RPM wise.
Yes adding pitch increases load, fuel consumption, EGT's, and reduces RPM.
The props on my boat were 28X33 and I had them add a hundred RPM which took them to 28X31. If I did it again I'd go to 28X30.
The interesting thing is I don't think I lost any speed taking pitch out.
Fuel wise at 1800 RPM I'm burning 35 GPH combined and running 23 MPH; that's pretty close to the sweet spot. Then at 2000 RPM, 44 GPH at 28 MPH. So, on the pins the engines are probably hitting the limiters with the max load shown.
My best economy cruise is 1800 RPM.

Interesting... I don't think I have lost speed by reducing pitch either. In 2019, when I tested the boat, we saw 35mph on the pins but we were running on less than 1/4 tank of fuel, holding and fresh water were empty. Boat had a 28x32 props then.

Best prop size for me seems to be the 28x30.8" that I am running now. Also, based on MPG there isn't much difference running 1800-2000 RPM's, .63 mpg (36gph and 22mph) or .65 mpg (41gph and 27mph) respectively.
 
I didn’t notice my load at full throttle in the past but now I am curious so I will check it out this spring. Here are my numbers. My fuel burn has always been a little off between the engines.

View attachment 122857

Jeremy:
Question - On your VV, the chart on the left side where you show the GPH for each engine. Does that tend to disappear randomly for you? If I want mine to show, I have to select the table every so often for some reason. It never just stays showing.
 
Same here

Not sure why Mercury would make that HIDE automatically. It must be time elapsed but not sure I have seen a set pattern. Wonder if there is a setting for this? I will look next time I am at the boat.
 
Not sure why Mercury would make that HIDE automatically. It must be time elapsed but not sure I have seen a set pattern. Wonder if there is a setting for this? I will look next time I am at the boat.
I have no set pattern or time on mine. Sometimes it stays on until I change it. I have tried short holds, long holds and didn’t make a difference it just did what it wanted. I say it’s doesn’t want me to know fuel burn!
 
Jeremy:
Question - On your VV, the chart on the left side where you show the GPH for each engine. Does that tend to disappear randomly for you? If I want mine to show, I have to select the table every so often for some reason. It never just stays showing.
Mine does not go away. The only thing I have to do each time I start the motors is push the GPH field so that I can see both motors individually. When I first start the engines it shows total GPH.
 
Interesting... I don't think I have lost speed by reducing pitch either. In 2019, when I tested the boat, we saw 35mph on the pins but we were running on less than 1/4 tank of fuel, holding and fresh water were empty. Boat had a 28x32 props then.

Best prop size for me seems to be the 28x30.8" that I am running now. Also, based on MPG there isn't much difference running 1800-2000 RPM's, .63 mpg (36gph and 22mph) or .65 mpg (41gph and 27mph) respectively.
It interesting that it seems like most of you are burning less fuel than I do at a given RPM and are getting a few more MPH as well. I have the 800lb tender sitting on the swim platform. Also it is a hydraulic platform so there is probably a couple hundred pounds there too. Maybe that hurts my numbers?
 
It interesting that it seems like most of you are burning less fuel than I do at a given RPM and are getting a few more MPH as well. I have the 800lb tender sitting on the swim platform. Also it is a hydraulic platform so there is probably a couple hundred pounds there too. Maybe that hurts my numbers?

What are your prop sizes? I also have hydraulic platform. My tender is in the 550lb range though.
 
I believe the port engine has an additional gear which makes the port prop turn counter clockwise to the engine. The additional gear will increase the load & fuel burn over the starboard engine as I was told.
 
What are your prop sizes? I also have hydraulic platform. My tender is in the 550lb range though.
I have to look to be sure but I thing I am at 28x30.
 
I believe the port engine has an additional gear which makes the port prop turn counter clockwise to the engine. The additional gear will increase the load & fuel burn over the starboard engine as I was told.
Both trans have counter-gears and the counter gears always rotate when the engine is running. The difference is one clutch pack uses the counter-gear and one does not. But it does take more energy for a given RPM through the countershaft than not.
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Both trans have counter-gears and the counter gears always rotate when the engine is running. The difference is one clutch pack uses the counter-gear and one does not. But it does take more energy for a given RPM through the countershaft than not.
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Interesting. I wonder if SeaRay accounted for this with slightly different pitch props.

Again until my most recent runs with these newly conditioned props my Effeciency numbers between port and starboard were very close.
 
Discoloration on transom door. My transom door is showing a black mold-like spots on the finish actually looks to be below the finish. It seems the transom door isn't fiberglass. All traditional cleaning doesn't seem to change the condition at all.
Any suggestions or similar condition?
Tom

Tom
Not sure where you are on this transom door issue but ran across this replacement door and thought you might be interested. Also states build to order.

661886F5-4280-45A8-96D2-30E87020DC73.png
 

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