Proper prop?

Have a 1982 17' Galaxie v-hull with Mercruiser 470 and 19p prop. Does this sound about right? It's an aluminum 3 blade, and I do seem to jump and plane fairly well, with a top end speed of around 42 mph if my gauge works correctly. 4 months since on the water, so I don't recall my rpm. Just wondering if I could do any better on overall performance. I'm not looking to race, rarely pull a skier, and just want to get across the lake to where I'm going in a fairly quick manner. This is my 3rd boat, but the first two were smaller outboards, so I'm not well versed yet.

Re: Proper prop?

I would say your close If you get us the full numbers in the spring,hp,rpm rating present max rpm and speed.In the meantime be sure it is properly tuned,throttle is opening all the way,present prop in excellent shape.I don't know what a 470 is but from your description I'm guessing something like about 120hp.

Re: Proper prop?

4states said:

with a top end speed of around 42 mph if my gauge works correctly...

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It doesn't, they are notoriously innaccurate. The best all around prop for the least amount of money is the Turning point Hustler/Legacy. Of course, without the proper info, nobody can make a good recomendation. Fill in the blanks this spring and we'll find you a prop.

steelespike said:

I don't know what a 470 is

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It is the 3.7L frankencruiser. rated 160-195 hp at the crank.

Re: Proper prop?

Wow 160 to 195 in a 17 footer at 42 Something isn't right Get us the info suggested
we'll try to help you figure it out.Check out the stickies at the top of the page and the helps on the prop store page.

Re: Proper prop?

steelespike said:

Wow 160 to 195 in a 17 footer at 42 Something isn't right

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So which part doesn't seem right? My current prop is in pretty good shape... I believe it was new last summer (bought boat in July), and there are no nicks or wear showing. The motor runs well, or it did at last trip out in september. I've kept it in the garage (heated) all winter, and will be doing a minor tune up before hitting the water (changing plugs, checking cap and rotor, clean air filter, change oil and coolant. Stabil was added to gas before parking, too.)

Re: Proper prop?

In my opinion with that motor in 17 ft boat should be in the 50 mph range.
If its really heavy or extremely deep V it might not make 50.
But typically an 18 footer with about 120 to 140 hp I/O will be in the 40+ mph
range with a 19 or 21" prop.Without actual max rpm ,speed and horsepower its difficult to know where to look.Perhaps the 470 is an odd ball setup but again I'm a little in the dark there.

Re: Proper prop?

Well i can give you an example of what my old 16' silverline bowrider with a mercruiser 470 would do. First of all the wot operating range is only 3800-4200. The lower unit drive ratio is 1:84 to 1. After installing petronix electronic ignition ( highly recommended ) alternator converter kit ( again highly recommended) replaced 3 inch heat exchanger for 4 inch ( a must if you want to keep temperature in control) rebuilding the carb, and putting on new exhaust risers, i was able to hit 49 gps at 4400 rpm with an Apollo Stainless prop 23 pitch small diameter prop i got from propmd.com for $239 including the hub kit. I am assuming your 17' boat may be a little heavier than mine and also i am running in 900 ft above sea level with an optimally tuned rig. If you are getting 42 gps out of a 19 pitch prop i am pretty sure you may be overreving a bit at top end. I would try a 21 pitch and see what that gets ya!! Good luck

Re: Proper prop?

Here is a video of my old boat cruisin down the lake at about 3/4 throttle. I love the sound of the old merc 470 ( for a 4 banger )

http://www.youtube.com/watch?v=3Uu7yj1PAzU

Re: Proper prop?

I have a mercruiser 470 also and the 470 is a 170hp motor. I have a 21 pitch prop on mine, it's a 18 foot boat. You guys think this is the best pitch for my motor