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Author Topic:   right prop size?

hlebowi2 posted 03-12-2003 08:21 AM ET (US)
Well, I am buying a slightly used 90 2 stroke Merc to replace my 1985 Mariner 90 on my '85 17' SS. The new motor has a stainless steel 13 1/4X19X4 blade prop on it already.The former owner called Ed's Marine and they quoted him $488 for a new prop just like this one, so it is expensive. Any thoughts about how this prop will work for me? I usually have the boat pretty lightly loaded.
Thanks,
Howard
Bigshot posted 03-12-2003 10:10 AM ET (US)
Should be good, makes that deal sweeter.
newt posted 03-12-2003 01:01 PM ET (US)
This may not be applicable, but on my montauk with the same motor and a three bladed aluminum, I run a 21 pitch prop and lightly loaded, it will still over-rev.
Will a four bladed stainless prop slip less? Enough to make up for the 2" in pitch?
Bigshot posted 03-12-2003 02:15 PM ET (US)
newt if you stepped up to just a SS prop you would drop a 100 rpm's plus. Going to a 19" 4 blade is even more. I think that 19" will be about perfect from what I have read here, if a tad too small you can have it double cupped which will bring it to a 20" and that costs peanuts to do.
hlebowi2 posted 03-12-2003 08:23 PM ET (US)
Thanks for the input.
I'm glad I can use the prop already on the engine, and that you think the deal might be ok with the addition of the $500 prop, Bigshot. That makes me feel better about the purchase.Also, I guess I can buy a 4 year extended warranty from Mercury because the initial warranty doesn't run out until 6/13/03. The number thrown around is $800. Is this worth it, do you think?
Howard
lhg posted 03-12-2003 08:38 PM ET (US)
The prop being described sounds like a Mercury 4 bladed Trophy performance prop.
That prop was specifically designed as a flats/bass boat prop for elevated running, with the Merc 75-125's. If it will turn up the required 5500 RPM's, it will be a screamer. But the engine MUST be mounted in AT LEAST the middle (3rd) set of holes for it to run properly, maybe the 4th set. It cannot be run fully submerged, as it takes a huge bite on the water, and would be more like a 23" effective pitch. I guarantee you it will not be too low in pitch. If anything, it will be too high. This prop gives great bow lift, and practically no steering torque. Your boat should do close to 50 with it.
If it's an aftermarket Stilleto prop, and not Mercury, disregard everthing I have said!

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Author	Topic: right prop size?
hlebowi2	posted 03-12-2003 08:21 AM ET (US) Well, I am buying a slightly used 90 2 stroke Merc to replace my 1985 Mariner 90 on my '85 17' SS. The new motor has a stainless steel 13 1/4X19X4 blade prop on it already.The former owner called Ed's Marine and they quoted him $488 for a new prop just like this one, so it is expensive. Any thoughts about how this prop will work for me? I usually have the boat pretty lightly loaded. Thanks, Howard
Bigshot	posted 03-12-2003 10:10 AM ET (US) Should be good, makes that deal sweeter.
newt	posted 03-12-2003 01:01 PM ET (US) This may not be applicable, but on my montauk with the same motor and a three bladed aluminum, I run a 21 pitch prop and lightly loaded, it will still over-rev. Will a four bladed stainless prop slip less? Enough to make up for the 2" in pitch?
Bigshot	posted 03-12-2003 02:15 PM ET (US) newt if you stepped up to just a SS prop you would drop a 100 rpm's plus. Going to a 19" 4 blade is even more. I think that 19" will be about perfect from what I have read here, if a tad too small you can have it double cupped which will bring it to a 20" and that costs peanuts to do.
hlebowi2	posted 03-12-2003 08:23 PM ET (US) Thanks for the input. I'm glad I can use the prop already on the engine, and that you think the deal might be ok with the addition of the $500 prop, Bigshot. That makes me feel better about the purchase.Also, I guess I can buy a 4 year extended warranty from Mercury because the initial warranty doesn't run out until 6/13/03. The number thrown around is $800. Is this worth it, do you think? Howard
lhg	posted 03-12-2003 08:38 PM ET (US) The prop being described sounds like a Mercury 4 bladed Trophy performance prop. That prop was specifically designed as a flats/bass boat prop for elevated running, with the Merc 75-125's. If it will turn up the required 5500 RPM's, it will be a screamer. But the engine MUST be mounted in AT LEAST the middle (3rd) set of holes for it to run properly, maybe the 4th set. It cannot be run fully submerged, as it takes a huge bite on the water, and would be more like a 23" effective pitch. I guarantee you it will not be too low in pitch. If anything, it will be too high. This prop gives great bow lift, and practically no steering torque. Your boat should do close to 50 with it. If it's an aftermarket Stilleto prop, and not Mercury, disregard everthing I have said!