New Mercury 4 Stroke V8 RPM'S @WOT

[Bowman1]

Engine S/N: 2B596665
2019 21 XRS Bullet w/Mercury 250 Pro XS V8 4 Stroke

I was wondering if you guys know anything about setting the throttle signal which I was told is a voltage signal that needs to be set with a laptop to achieve 100%. My question is does it also have a feedback signal telling it that the throttle is actually traveling 100%? I was running a 28p Bravo XS prop going 75mph @5740RPMs. I tried a 26p Bravo XS and I only got 76mph @5870RPMs. Seems like I should have gained allot more RPMs at WOT.

[Jordan99]

May have to drop to a 24 or 25p. I know when i first got my 4s merc i had to drop down a pitch for the prop I was running on my 2s optimax. I recently purchases a 24p fury to try and see if i liked it better than the 25 I am running now. I bumped 6200rpm and had a great hole shot but it was just a little slower than the 25

[Sandman123]

HAVE PROPS BEEN WORKED? ANY ADD/REMOVE OF WEIGHT OR HEIGHTS? LOOKS LIKE SLIPPAGE BETWEEN PROPS ARE DIFFERENT.

[EuropeanAM]

Of course the slip is going to be different between two different propellers.

To accurately determine if the throttle is reaching 100%, it will be necessary to get the engine on the Dealer G3-2019 Computer Diagnostic System.

This gearcase design does require lower pitch numbers than were used with some previous models, due in part to the substantially improved gearcase geometry.

[BuddyT]

I have had several conversation with two guys, Scott Reichow and Rick Mackie, from Mercury Racing. The Bravo XS props when casted are all made with even pitch 1 inch apart: ie 24,26,28. When they developed the odd pitchs all they did was add cup. The 1st of Bravo XS, came out in 2011, with the 8 pvs holes where only avaible 1 inch pitch changes. In 2015 Mercury Racing interduce the 1/2 inch sizes. All Bravo's, XS, FS, LT and such run low in their true pitch size: ie a 27 inch runs like a 26 Tempest. What this boils down to is they make a 24 pitch, then add some cup and call it a 24 1/2, then add some more cup and call it a 25, and one more time they add some more cup and call it a 25 1/2. Then to make a 26 is a new casting, all this info comes from the Mercury Racing website under the Blogs. I run a 27 inch in the winter time, and a 25 1/2 in the summer. My boat is a Triton 21HP with a 250 Pro XS 2 stoke, the boat is heavy loaded and that is where the Bravos XS shine, great mid range with a little loss on top end. I was concerned with prop slip with my 27 inch prop, talked to Scott and he told me to run it as a 26 inch with Mercury prop slip calculator and the numbers will be right. Hope this helps about the props.

[Bowman1]

I think I may have found my issue. I found a broken alternator belt which was caused by the pulley on the crankshaft breaking. That may have created some drag. Not sure.