BAMORY

Trying to find out what best prop size for speed on this behemoth is. 1984 Scarab III 34 foot....Twin 454/370 BW and TRS average drive ratio's....running Mirage 23P now.

Is there a better prop, I cannot spin over 4000 rpm now, that is with the sticks pushed to the bow...... but then again......what is my WOT on this boat??

MILD THUNDER

iTrader: (3)

Something is not right. My buddy has the same boat, same engines. He turns 22p Hydromotive's to around 5000rpm. You should be turning the 23 mirage props to close to that.

Is it bottom painted? Are you trimming the drives out and raising the tabs up? That boat with 370's should be running 55-60mph.

BAMORY

Got it up to 53 gps today on Erie with glass water. But still nothing after 4000-4100 rpm. Tach's accurate as far as i can tell. She definitely sounds like she has more to go. Sitting in the slip, I can bring tach up to 4800 slow and easy, but i rev no further.

Tabs were half way down till plane, then retracted. Drives were trimmed up to to rooster tail point then tucked back in when I lost 2-3 mph on gps.

Any suggestions.....I still don't know what WOT is on these motors.

Oh and not painted, but scrub at sandbar weekly. This speed is consistent since I put in water in May.

Scarab3DMC

Mid thunder is correct, I have run 22" hydros and 23" pitch Mirage Plus, 58-60 mph @ 5000-5200 rpm, have you had the props checked? I have found that Hydromotives Quad - 4's worked the best, 9-11% slip, real reactive to trim, My Scarab III is a 1983, I had 525 SC motors and went to 27" Q-4's and picked up 14 mph, Now I have 565 cuin, 600hp/650 ftlbs, still with the 27's @ 78 mph.
I have ovned this boat since 1999 if you need any help you can give me a call @ 440-773-1833 Dave

BAMORY

Thanks Dave and Mild Thunder- The only thing I can tell is that I am not using K-planes once I get on up on plane. Have them tucked all the way up. But I am on plane. With these 454's whether it be the 330/370/440 hp engines, I should be able to attain what WOT?

Unfortunately, she is in the water and I will probably not bring her out till fall. I have a laundry list of improvements and repairs that are needed due to previous owner just not fixxing things when they break.

Trim indicators only work half the time, no idea where my K-planes are, port tach is jumpy @ times. Got some work ahead of me. I do however know that my drives are out to the max for planing based upon my speed and through trial and error I know my tabs are retracted.

Scarab3DMC

try 21
' pitch props

BAMORY

Hey Dave....if you use Facebook, add me.

Bruce Amory

Scarab3DMC

10-4, where do you keep her?

BAMORY

I am up @ Bass Haven Marina, Marblehead. Nice marina, but the depth of East Harbor concerns me. I get over to Huron quite often as my daughter/son-in-law has a cottage around Nickelplate beach. Sandbar off Cedar Point is a great place to be, and lets not forget the Barge Parties.....July 30th is the next one.

502ss

iTrader: (3)

Just throwing this out there....

How new are you to the boat? Any chance your not getting full throw on the throttle plates?