The engine in my boat is a Mercruiser 5.7L 260MR. When I ordered my drive in April, the dealer told me he thought it would take a 1.5:1. He then called me the next day and said that SE told him it should be 1.65:1 and so that is what he ordered. He said if it was wrong, it was no major problem. It would just require a different prop.
When I ran the boat with the new drive, it seemed sluggish. I bought the boat knowing that it needed a new drive, so I never personally saw how it accelerated with the old drive, but the previous owner told me that the boat cruised at around 22 MPH and topped out at about 32MPH.
With the new drive, I'm cruising at about 17MPH and I top out at around 24MPH.
It also seems pretty slow to accelerate and reach a plane. As I said, I don't have any previous reference to compare it to, but the boat always feels like it is struggling to move along.
By coincidence, today I happened across the original manual in a locker behind the dash.
The manual lists the standard ratio as 1.5:1 with an option to use 1.32:1. (I don't know what this option is or why you would choose it). The point is, they don't list anything above 1.5:1.
They also list the RPM range at WOT as 4200 - 4600. My RPM at WOT is right around 3800.
My dealer told me to bring him the old prop and he would take a look at it and let me know what prop I should change to. Before I spend money on a new prop, I'd like to know if this is the right approach to solving the problem.
Thanks in advance for your assistance.
When I ran the boat with the new drive, it seemed sluggish. I bought the boat knowing that it needed a new drive, so I never personally saw how it accelerated with the old drive, but the previous owner told me that the boat cruised at around 22 MPH and topped out at about 32MPH.
With the new drive, I'm cruising at about 17MPH and I top out at around 24MPH.
It also seems pretty slow to accelerate and reach a plane. As I said, I don't have any previous reference to compare it to, but the boat always feels like it is struggling to move along.
By coincidence, today I happened across the original manual in a locker behind the dash.
The manual lists the standard ratio as 1.5:1 with an option to use 1.32:1. (I don't know what this option is or why you would choose it). The point is, they don't list anything above 1.5:1.
They also list the RPM range at WOT as 4200 - 4600. My RPM at WOT is right around 3800.
My dealer told me to bring him the old prop and he would take a look at it and let me know what prop I should change to. Before I spend money on a new prop, I'd like to know if this is the right approach to solving the problem.
Thanks in advance for your assistance.
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