How fast??

[Adamranger]

How fast should a r81 sport run with a 175 opti

[turfy49431]

63-65 with a 25 tempest (worked)
61-63 with a four blade

mine was dialed and would run 65-67 all day long with a B & B 25 tempest that was done by Boger Props back in the day. 6" plate at 3.25 prop to pad 5950 rpms. Merc 175 EFI

[Adamranger]

I'm hitting 57-60 with no plate and I'm not sure which prop.

[turfy49431]

How many rpm's? Look for some kind of markings on the prop and post back here. More than likely your motor is too deep and your not running enough rpm's. You should be around 5900

[Adamranger]

It's a tempest plus. 48-825866 25p

[bassnman81]

I have a 2000 R-81 and replaced the 175 EFI with a 175 Pro-XS. With the 175 EFI it ran 72 GPS (fact, not going to debate it). The Pro-XS will only run 64 GPS. Tried different props and engine heights. My Mercury guy said it's because the old EFI actually had more than 175 out the prop. I run a Tempest Plus 23P, it runs around 5900 RPM, strong hole shot too. The R series boats are fast, good luck with it.

[basscat tyler]

I have a 2000 R-81 and replaced the 175 EFI with a 175 Pro-XS. With the 175 EFI it ran 72 GPS (fact, not going to debate it). The Pro-XS will only run 64 GPS. Tried different props and engine heights. My Mercury guy said it's because the old EFI actually had more than 175 out the prop. I run a Tempest Plus 23P, it runs around 5900 RPM, strong hole shot too. The R series boats are fast, good luck with it.

The old 175 EFIs were beasts.

[71bambam]

have one get 70 gps out of it you need a 6" jackplate on it run an a45 tempest b&b by croxton and put a 200 efi brain box on it got me 3 mph