Cord

Glass-I've found the mirage to be one of the poorer planing props when the x-dim is high. I know that cat's like a high x-dim, so the fact that you could even get on plane with a mirage told me that your drives must be deep. Many stern drive cats like the bravo 1 prop. What is the cut down version called? The revolution? Anyways, if you were to raise the x, then I'd be looking at the rev. Until then, I'd proably just stick with a 3 blade round ear (especially if you are looking to get out of the boat).

glassdave

thanks guys, great advice! . . i just got back from skiing this weekend so i wasnt able to catch up on the thread till now. i am going to do somthing with my current props in the next few weeks. they have a few dings and need to be gone over. the accelerator sounds very intriguing. i have heard good things about that service. actually i really like these quicksilvers i have now. they cary the bow real nicely. i love the attitude i get out of them but like i say i can only get em up to like 4200.



throttleup- you make some good points. i may have to research some cams a little more. i was basing my upgrades on a similar motor i did for a 24 foot Mirage i had before this boat. i will probably do some prop testing this summer. i was thinking i should run these to about 4600rpm. they have about 400 hours on them and are in great shape. is it ok to run the stock merc long block at 5000prm? i dont plan to run it on the pins all the time mostly just to maximise what i have to keep me happy for another season or so. thanks

throttleup

Glassdave,

4600 would be a good rpm for the stock motor. But to get the most out of the upgrades you have done you will need to get the motor running at it's peak HP rpm. Without any cam information it's hard to tell what rpm your new motor needs to run at.

We just went through a similar situation with a local customer. He had an HP500 and rebuilt the motor but changed the cam along with some other parts. When he was done the boat was slower than it was stock. When we got him propped out to run at 5800 he picked up speed over his original motor. He didn't want to have to run at 5800 so his only other choice was to change the camshaft. Make sure the camshaft will work properly at the rpm you want it to.

As far as the durability of your motors we wouldn't be the ones to say if they will hold up or not. We only work on props. With all the high performance boats we work on we just make sure the props run at the optimum engine rpm. Whether the motor will hold up at higher rpms, I really couldn't tell you.

Matt

glassdave

thanks T-up. actually i havent done the motors yet ( still to dam cold here ). i have just rounded up all the parts although i think i will need to look into my cams a little more, may hafta start a new SBC cam thread . . . Dennis Moore!! . .help!!!

p4-33

Glass,

A while back, I had a CC 260 Stinger with stock 260's and Alpha's. I ran Merc Mirage Plus 23p props and loved them. It ran 4900-5000 at WOT and topped out at 60mph. The thing I liked about them is that from a standstill, I could tuck the drives, and literally jam the throttles without a lick of cavitation. When running poker runs with bigger powered boats, this is a big advantage to get out into clean water before the wakes are everywhere around you.

I still have these props sitting in the garage if you're interested. Excellent condition, both RH rotation. I'm in Gibraltar, MI, so they would be easy for you to take a look at. I can also email pictures.

Just giving you options....

Good luck,
Brian

p4-33

P.S. What year is your Scorpion? My Stinger was an '88, so I don't know what, if anything, Chris Craft did to the hull performance wise between the two models.

I just re-read this post and I am a bit confused why you're only seeing 4200rpm with your current 23p Quicksilvers. Something doesn't add up. I just went out ot the garage and double checked that mine are indeed 23p, and they are.

So the question is - Did CC make big changes to the hulls between the Scorpion and the Stinger for better performance? Is the Mirage Plus prop that much better of a performer than the Quicksilver?

Maybe the OSO gods can shed some light...

Cheers,
Brian

p4-33

Last question...

How many hours are on your motors? Mine were brand new, and I put probably 200 hours on the boat. Is it possible your 260's are "tired" and not getting the power that they used to? You might want to do compression tests and leak-down while the motors are apart.

Brian

glassdave

p4-33- thanks for your input. i always like to hear how other owners ran. my boat is an 85 with good power they run well with about 400 hours on them. i got it from the original owner who i have known for years and know they has been well cared for. i think my boat is a bit heavier than the later years, they did some revisions in 85/86 and refined the boat a bit. most owners i know with the same hull are running 21's with stock 260's. the 23 QS's i am running now work real well, no cavitation or blow out at all. mechanically the boat is great. my original thought when i put up this thread was that i am needing to get my props cleaned up and if labbing would be worth the extra $$ at that time. after i do the engine mods this winter i hope to be able to spin the 23's better. i know will hafta do some testing and would like to contact you on the props you have. mine are both right hand also. thanks again Brian.



Great info guys . . this is why i am a member.

p4-33

Hi Dave,

When you're ready, send me email at [email protected]

Good luck with your motors.

Brian

p4-33

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