Max RPM on SHO engine?

[txbass1]

The reason why I started this thread is because I can only turn my 25 T-2 at 5500 rpm, that’s with a hydraulic jackplate. I recently got a 23 pitch Razor 4. I was concerned that by dropping 2 pitches with an overall smaller blade diameter, I could possibly be above 6000 rpm. Well that wasn’t the case. I got to run it on Lake Toho this past week, low 80 degree air temps and water temps in the mid 60’s. I really had to run it pretty high on the jackplate. 8 on the Atlas, trimmed really high, I was able to get her up to 70 @ 5800 rpm’s. I have a BassCat Caracal, and the Cats generally don’t like much trim at all. But to get the bow up and rpm’s up, I had to run everything really high. Also, the hole shot was really poor, had to set the jackplate at 12 just to get a decent hole shot. It was much slower than the 25 T-2. Do y’all think I have an engine issue? Or is it just a weak engine?

Yes, something is not right with that motor.

[Bradley21SS]

The reason why I started this thread is because I can only turn my 25 T-2 at 5500 rpm, that’s with a hydraulic jackplate. I recently got a 23 pitch Razor 4. I was concerned that by dropping 2 pitches with an overall smaller blade diameter, I could possibly be above 6000 rpm. Well that wasn’t the case. I got to run it on Lake Toho this past week, low 80 degree air temps and water temps in the mid 60’s. I really had to run it pretty high on the jackplate. 8 on the Atlas, trimmed really high, I was able to get her up to 70 @ 5800 rpm’s. I have a BassCat Caracal, and the Cats generally don’t like much trim at all. But to get the bow up and rpm’s up, I had to run everything really high. Also, the hole shot was really poor, had to set the jackplate at 12 just to get a decent hole shot. It was much slower than the 25 T-2. Do y’all think I have an engine issue? Or is it just a weak engine?

Yeah somthings not right. I’m sure motor is fine though! Probably throttle cable

[mwadkins]

Yeah somthings not right. I’m sure motor is fine though! Probably throttle cable

I pulled the cowling yesterday. And if I’m looking at it correctly, the witness marks matched up with the hot foot fully depressed. It just really surprised me that it was so slow out of the hole. It really boggles my mind that a buddy can turn his 25 T1 on his 200 Zx with a 200, and I can’t turn a 23 pitch 4 blade.

[FrankWhoa]

The reason why I started this thread is because I can only turn my 25 T-2 at 5500 rpm, that’s with a hydraulic jackplate. I recently got a 23 pitch Razor 4. I was concerned that by dropping 2 pitches with an overall smaller blade diameter, I could possibly be above 6000 rpm. Well that wasn’t the case. I got to run it on Lake Toho this past week, low 80 degree air temps and water temps in the mid 60’s. I really had to run it pretty high on the jackplate. 8 on the Atlas, trimmed really high, I was able to get her up to 70 @ 5800 rpm’s. I have a BassCat Caracal, and the Cats generally don’t like much trim at all. But to get the bow up and rpm’s up, I had to run everything really high. Also, the hole shot was really poor, had to set the jackplate at 12 just to get a decent hole shot. It was much slower than the 25 T-2. Do y’all think I have an engine issue? Or is it just a weak engine?

The smaller diameter is hurting your hole shot and the four blade down 2 pitches it actually more like a 3 blade down 1...

The SHO has the torque to spin the bigger diameter rather than the rpms that a 2 stroke would use on a smaller diameter.. this is for the hole shot.

[skennedy]

Not really all true with comparing 3 blades to 4 blades . I run a trophy 27 and a tempest 27 . Loaded on tournament day there is only 50 rpms difference . the 4 blade turns less rpms but out paces the 3 blade by a solid 2 mph on the top end . Hole shot only by a slight margin goes to the tempest . This is on basscat puma with 250 . I run the tempest the most in the summer heat . The difference is with the motor heights and thing have to be adjusted on the fly and dailed in for best performance out of the hole and top end . The trophy is small dia prop and it kicks ass . Plug all the holes and a exhaust ring .

[FrankWhoa]

You're correct, what I said is a general rule of thumb for most applications. Prop slip, hull weight, prop to pad all matter too.

I tried a 25, 26, and 27 tempest. The 25 t1 by far was better in every category. This is with a hydraulic jackplate though because prop to pad is critical.

I have never tried a four blade on my setup but I've been told that going up a blade and down a pitch is the same as you are already running. Then you can see the difference the extra blade gives you as it relates to slip or drag assuming diameter stays the same. Factor in diameter and prop to pad then you're good to go... if you're close already... usually lol

Now my buddy ran a 4 blade on his bass cat and she booked it. I have a skeeter.