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Thread: Nose cone and prop
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05-10-2020, 12:42 PM #1Member
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Nose cone and prop
Hey guys
i just finished my Nose cone and took the boat for a test run.
the reason I mounted the cone was that I needed lwp since I couldn’t raise the engine high enough without loosing pressure, And I needed more lift since the boat was running to flat and with a lot of chinewalking. so my guess was that the engine needed to run higher and with a bigger/other prop.
my goal was to reach 85+ mph.
the boat: Fletcher 199, 225 optimax, 6” setback, hydraulic jack plate.
before installing the nose cone:
propshaft 1.5” below the pad.
27p tempest plus (blueprinted & labbed).
WOT 77-80mph/5600-5650rpm.
after installing the nose cone:
propshaft in Level with the pad (jack plate is at maximum height)
27p tempest plus (blueprinted & labbed).
WOT 68mph/5200rpm.
what the hell happened?
i then tried a stock 28p promax (4 blade) and this gave a bad hole shot (guess because it hasn’t got pvs holes as the tempest), but I got a rock solid boat without any chinewalking at all.
WOT 73mph/5450rpm.
The million dollar question is now:
1). can the promax be modified to a 29-30p and at the same time be labbed to getting around 5600 rpm.
2). should I dismount the jack plate and raise it so I will be able to getting the propshaft 1-2” above the pad.
Please give me your thoughts guys
thomasLast edited by Ttl; 05-10-2020 at 12:50 PM.
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05-10-2020, 03:31 PM #2
I'd try some more props. Cleaver, chopper, lightning etc
Hydrostream dreamin
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05-10-2020, 07:22 PM #3Team Member
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Does it have less bow lift with the prop running higher?
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05-10-2020, 11:40 PM #4Member
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Yes I think it does
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05-11-2020, 11:08 AM #5
Any prop shops near you? Get some cup added it should help with lift. Trophy is another I forgot to mention, I havent tried one yet but plenty of fans for the holding power of that prop. Mazco is another that has good lift. I have a Mazco as well and its good but the chopper I have which has been massaged more times than I could ever tell holds really really well. It is a pain to get out of the hole with a stock through hub exh but it grips and lifts big time under power
Hydrostream dreamin
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05-11-2020, 08:21 PM #6Team Member
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Try props with more lift or try lowering the engine. I think you get more lift lower
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05-12-2020, 04:11 PM #7
Ya the higher u run the less lift u get , I been kinda fighting same thing , I just put a trophy on and it's better but the trophy needs little work to be what I want , I want a bravo xs to try. Also a stock big ear chopper has great lift ,
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05-16-2020, 12:28 PM #85000 RPM
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Sounds like your boat needs bow lift which mean positive engine trim. By adding a LWP you made your gearcase longer. With positive trim, a longer gearcase creates more drag which may be slowing you down. Yes, raising an engine will reduce bow lift but it will also get more of the gearcase out of the water reducing drag. A power jackplate will save you a lot of setup time. Also, increased setback may help to get you bow lift back at higher engine heights.
I'm in a similar situation...Sportmaster lower, heavy setup, and mid to upper 70's for speed. I run about 1"-2" above the pad for speed. At the higher engine heights with positive trim, larger diameter props with lots of cup seem to work the best -- Scorpion 3-blade or mod'd Bravo. I also like the TXP OT4. The Promax was great for speed but terrible, surging hole shot.
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05-16-2020, 12:47 PM #9
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05-16-2020, 01:12 PM #10Member
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phillnjack liked this post
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11-15-2020, 12:26 PM #11
How is the motor only 11/2 inch up using a jackplate ? the jack plate should be able to lift that motor atleast 5 inches higher than you previously had it.
what are you doing exactly to have it this low when motor is raised fully up ? are you mounting the motor on its lowest holes and have the jack plate itself mounted too low ? most jack plates will automatically have atleast 1 inch lift without even moving the plate up, then you have the rest of the lift itself, so I cannot see how your only up 1 1/2 inches. or is this a case of you dont want to run it higher and get the bullet riding on top of the water ?
where is the cavitation plate running now you have the jack plate on at full throttle / you need that to be above the water by about 2 inches. the lwp will do the job of getting plenty of water pressure even if you go up another3 inches... you realy need to see what is happening at the cav plate when running on the plane.. to me it sounds like your too deep, and with the cone you have more case in the water causing more drag... and if plate is lowthat will also be getting drag
just how im seeing this..
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11-15-2020, 01:56 PM #12
You raised the motor 1.5 inches and LOST 400 RPM??? This just doesn't seem possible
Living in the Freedom provided by Bud Conner and his fellow warriors.
R.I.P. my Heathen Brother
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11-15-2020, 02:29 PM #13Screaming And Flying!
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Weak coil
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11-15-2020, 04:44 PM #14
Weak something
Living in the Freedom provided by Bud Conner and his fellow warriors.
R.I.P. my Heathen Brother
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11-15-2020, 05:17 PM #15
You didn't do anything other then the nose cone and raise the motor... weren't under the cowl at all hit a wire etc?
LETS GO BRANDON.... LETS GO BRANDON
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'84 Checkmate Convincor
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