prop replacement recomedations

[mr300z87]

I recently got my 93 Stingray 556zp(185Lx) Mercruiser 3.0L out for the first time. The boat ran awesome. We had 2 adults and 2 medium size children (up front) with minimal equipment and 3/4 tank fuel. According to Stingray the dry weight is about 1800lbs. It currently has what looks like the original equipment (part# matches Stingray spec) prop 21p x 13 3/4 actuall measured diameter 12.5???. The prop is showing its age and although the hole shot was descent I feel the top end was a little off. WOT netted 4400 RPMs but top speed via GPS was only 33 - 35 MPH. Conditions were light wind with a slight chop. We were able to cruise nice a 3100 rpm in the mid 20s mph. Since I am not looking to win any top speed awards, just good comfortable cruising with the family and some water skiing and tubing I am considering a Solas Amita 3 21 x 14.3 as a direct replacement. And possibly a Amita 3 19 x 14.5 down the road once I can re learn to slalom (its been 8 years) for some added hole shot. I would use the 21 for just cruising and switch to the 19 for a day of skiing. Please let me know if I am headed in the right direction and how the Solas props compare to say the OEM/Michigan Wheel or others as the price is right on the Solas. Thanks in advance for any responses. Have a great day

Mike

 

[craze1cars]

Re: prop replacement recomedations

The Solas props are generally a bit more cupped/raked, and a bit more aggressive in bite. Therefore they will reduce your RPMS a bit compared to many aluminum original props. Therefore I think I'd suggest you purchase the 19 pitch before you buy another 21 pitch in that brand. I wouldn't be surprised if it gains you a little more holeshot, a little more RPM, and a little more top speed. A 21 in that brand may lug your motor down to 4200 or so which would be bare minimum and may hurt your holeshot. I'd guess the Solas 19 would move you close to 4600 which IMO would be better for a 3.0L equipped boat that tends to be a bit underpowered. FWIW that "3.0L" is the 115 hp version...the weaker 3.0 offered in the 1993-ish model years. If you actually have a "3.0 LX", that would be the 135 hp version of the 3.0 that was produced during those years.

I don't think you'll gain anything by switching props from one day to the next. Just pick the one that works best overall, and leave it on the boat. Keep the other as an onboard spare in case you hit something.

That's my recommendation/guess anyway...for Solas, go 19.

 

[mr300z87]

Re: prop replacement recomedations

Craze1cars, I went with your suggestion and bought the 19. It arrived on Thursday so I installed and tested yesterday. You were right on and I am glad I went with the 19, much improved holeshot from the beat up OE I removed. Top end has improved per the speedo but did not check with GPS, RPM up to about 4700 but she will hardly ever see that for more than a few min blast now and again. It was a little choppy out on Barnaget Bay yesterday so I only did one full throttle blast.

Do to the size and design of the the Solas prop I did have to grind some clearance on the Zinc Tab to be on the safe side. Will get a Merc offset one soon. All in all very happy with the new prop. Happy 4th to all.

 

[craze1cars]

Re: prop replacement recomedations

Thank you for reporting back. Not everyone does. It's helpful to know if any advice given is OK or off base....I will be first to admit that theoretical answers do not always work as predicted in the field.

Glad to hear it worked out in your case. Will be curious to hear your top speed if/when you get a chance to run it on some smoother water. Don't fear 4,700...that's nowhere near fast enough to actually hurt anything, even if you sustain it at that level here & there. Most 3.0's benefit from being underpropped a little bit like that, only becuase they tend to be a bit underpowered. As you have found, it's usually well worth it for the holeshot improvement.

Enjoy!