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Originally Posted by noli
(Post 4125772)
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What performance upgrades can be made to Merc 300 Promax ( not the 300X ) why is there still such a big demand for the 300 Promax ? . 1. I love not having to mix oil (verses 2.5) 2. I love the torque and being able to run over 100 @ 6000rpm 3. The 300 promax is probably the most reliable of the 300+/- hp Mercs because of the lower rpm, the lower compression. (requires less octane than the 300x) 4. I'm @ 500 hrs (5 times the safe usable 2.5 lifespan) and still bust 100 with 150 gallons of gas and 4 peeps. I have no intentions of tearing them down or modifying them and reducing their reliability. If I was to try and get a little more out of my max's, I'd probably just modify the rev limiter and let them turn 64/6500. |
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thanks NP for a personal insight into these engines. I couldn't understand why these motors sold in 1 day, but now I know why: [ from SnF classifieds , was sold to Ryan ] a set of 2000 mercury 300 promaxes FOR SALE!! A set of 2000 300 promaxes 20"mids ,1:75 sport masters ,just pressure tested ,fresh oil simmon poppets,carson reeds,stainless marine trim acuaters , in great shape,very clean 14,500 0BO $ plus shipping ,there in mercury crates PLZ CALL FOR ANY OTHER QUESTIONS THANKS Xxx 123 456 7890 plzz no tire kickers! Look at this beauty! PhotoCredit: Tom K http://i1238.photobucket.com/albums/...411_163221.jpg http://i1238.photobucket.com/albums/...411_174824.jpg http://i1238.photobucket.com/albums/...728_165922.jpg http://i1238.photobucket.com/albums/...411_173925.jpg http://i1238.photobucket.com/albums/...37166c2e3d.jpg |
Originally Posted by Nice Pair
(Post 4126087)
On a 27-28' boat the promaxes are desirable for a couple of reasons.
1. I love not having to mix oil (verses 2.5) 2. I love the torque and being able to run over 100 @ 6000rpm 3. The 300 promax is probably the most reliable of the 300+/- hp Mercs because of the lower rpm, the lower compression. (requires less octane than the 300x) 4. I'm @ 500 hrs (5 times the safe usable 2.5 lifespan) and still bust 100 with 150 gallons of gas and 4 peeps. I have no intentions of tearing them down or modifying them and reducing their reliability. If I was to try and get a little more out of my max's, I'd probably just modify the rev limiter and let them turn 64/6500. |
Originally Posted by bulletbob
(Post 4126322)
I agree entirely. I had modded 260s' (nicasil) then went to 225 promaxes (steel sleeve), removed the VOS tank, install a fuel pressure guage on motor and used the Weldon pumps already in the cat. I now have two years of running with just changing LU fluid every 10 hrs. Not even a plug change and as you stated they should run for several hundred more hours trouble free.
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Originally Posted by Nice Pair
(Post 4126087)
On a 27-28' boat the promaxes are desirable for a couple of reasons.
1. I love not having to mix oil (verses 2.5) 2. I love the torque and being able to run over 100 @ 6000rpm 3. The 300 promax is probably the most reliable of the 300+/- hp Mercs because of the lower rpm, the lower compression. (requires less octane than the 300x) 4. I'm @ 500 hrs (5 times the safe usable 2.5 lifespan) and still bust 100 with 150 gallons of gas and 4 peeps. I have no intentions of tearing them down or modifying them and reducing their reliability. If I was to try and get a little more out of my max's, I'd probably just modify the rev limiter and let them turn 64/6500. |
Those would probably be them car-motor thingies. It's hard to pound them into a 28' boat.
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2 Attachment(s)
Originally Posted by Nice Pair
(Post 4126627)
Those would probably be them car-motor thingies. It's hard to pound them into a 28' boat.
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Mine has a eating disorder. 80lbs of ballast in the front, nice stereo, sub box, tool box and no helium???
May have to get on Jim's program and join weight watchers. Nah just get bigger motors |
Originally Posted by Taboma
(Post 4125749)
I tested a set of 14.75X34 four blade Dewalds this weekend on my 28 Skater w/ 300xs's. What a great prop. Essentially got rid of the "hop", less buzzing, lifted the stern nicely and increased top speed. Raised the engines to 1.75"(spinning out) and was able to get to limiters at 109.8MPH. Pretty good for the lake conditions and a totally stock new boat and engines, in my opinion. My boat rides completely neutral as rigged - no need for ballast. By the way all, Shaun Torrente came up to Oklahoma to help me with the boat this weekend. I can't say enough about him as a humble yet knowledgeable guy that truly loves our boats. Regarding the Dewald props., Dave is still probably another month out on having ones for our types of boats due to casting issues from his vendor. David.
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Originally Posted by Nice Pair
(Post 4126627)
Those would probably be them car-motor thingies. It's hard to pound them into a 28' boat.
100 @ 5200 ... what pitch, how many blades, rake? You have my attention. |
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Originally Posted by Nice Pair
(Post 4126667)
"Skuse Me" sorry about the car-motor thing ... Nice whacker-boat.
100 @ 5200 ... what pitch, how many blades, rake? You have my attention. |
Dave Dewald is now suggesting 14.75 X 34,four blades for 300SX on a 28...FYI
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Sounds like I need a pair, Thanks.
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Originally Posted by Zero Patience
(Post 4126644)
28 Skater, 300 XS, Dewalds, and a strict Diet. No stereos, speakers, heavy batteries, has helium in the fenders and they are big fenders. Unnecessary weight removed from engines. If it's heavy it does not go in the Skater. Just enough fuel for the trip.
As far as mid range porpoise...mine does it from 60-70max...usually nail the throttles and it settles down immediately! |
Originally Posted by Zero Patience
(Post 4126781)
I followed the Leader, Double Rigged, 15.125 x 34+, 4 blade, cleaver, by Dave Dewald. Ron suggested them, he has a set. Don't know the rake, Dave does.
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Originally Posted by Taboma
(Post 4126840)
Dave Dewald is now suggesting 14.75 X 34,four blades for 300SX on a 28...FYI
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I've noticed that some outboard cats have a notch at the transom, and some don't like this XCat race boat. What does the notch do for the performance of the boat and why doesn't the XCat hull have them? I also noticed that the first step is way forward of the cockpit PhotoCredit: http://www.xcatracing.com/wp-content...07/advert1.jpg http://i1238.photobucket.com/albums/...ry/advert1.jpg same boat, pic of steps from a different angle http://i1238.photobucket.com/albums/...13Raf_0141.jpg |
my 28 and 30 have notched transoms. that Xcat steps are pretty aggressive compared to the skaters. the placement of them has to do with CG I believe. I would think they can be moved or modified a little from boat to boat huh???
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Noli...Steve 1 here on OSO can probably explain to us all about the steps and what not...didn't he have something to do with the Xcat ???
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I will check with Dave Dewald on the rake and post it when I know.
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LA what props are you running on your boat. I'm thinking of a purchasing a set of Mercury lab finished four blades 14.75 x 32". They did very well on my 28.
What do Dewalds cost and does anyone have contact info on them? |
Dave Dewald 610-926-2964
I had better luck with the Dewald 4 blades on my 32 skater, I messed with a set of mercury 4 blades for two years and couldn't make them work. I think the Dewald props are around $1,500.00 to $2,000.00 each. I think they are worth the money. |
Originally Posted by chardt
(Post 4128634)
Dave Dewald 610-926-2964
I had better luck with the Dewald 4 blades on my 32 skater, I messed with a set of mercury 4 blades for two years and couldn't make them work. I think the Dewald props are around $1,500.00 to $2,000.00 each. I think they are worth the money. |
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Have any of you with 30 and 32 footers ever tried Hering props? $3,600 a pair with 1 free adjustment. You pay shipping costs. http://i1238.photobucket.com/albums/...207_153407.jpg |
Originally Posted by noli
(Post 4128656)
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Have any of you with 30 and 32 footers ever tried Hering props? $3,600 a pair with 1 free adjustment. You pay shipping costs. http://i1238.photobucket.com/albums/...207_153407.jpg |
Originally Posted by Maritime_Eng
(Post 4128729)
Yes, I am running a pair now but they are thru hub cleavers. So far they are my favorite props I have ran on my boat.
Have you tried around-the-hub props, like Bravo1 style props in Hering? Have you tried Dewalds? I'm trying to find folks who've tried both and what their findings were. These two [ Dewalds and Herings ] is what racers and sportboat enthusiasts seem to like . |
Originally Posted by noli
(Post 4128757)
What pitch, diameter, rake are you using?
Have you tried around-the-hub props, like Bravo1 style props . http://www.offshoreonly.com/forums/s...ble-props.html |
Originally Posted by Maritime_Eng
(Post 4128729)
Yes, I am running a pair now but they are thru hub cleavers. So far they are my favorite props I have ran on my boat.
What's the story on the 24 Aronow with the diesel outboard?? |
Originally Posted by skate
(Post 4128843)
Can you give some more info about the performance with the Herrings. They are priced more competitively than I thought they would be.
What's the story on the 24 Aronow with the diesel outboard?? I had a set of Dewald 14.25 x 33p 5 Blade Thru Hub Cleavers and ran 108 @ 6150 RPM |
looks like I should check with herring and dewald...not as bad a price on the herrings as I was thinking.
skate...three blade 14 1/2 x 32's |
Originally Posted by LAriverratt
(Post 4128872)
looks like I should check with herring and dewald...not as bad a price on the herrings as I was thinking.
skate...three blade 14 1/2 x 32's We need to get together and see if we can get a better price if we buy together. I still haven't made up my mind what to buy. I need to re read Franks (AppSysCon) post on his 308 prop test. He tested five or more props. Unfortunately time to do research is not a luxury I have right now. Sam |
I tried the Dewald five blade thru-hull cleavers also. I did not like how my boat handled with them at low rpm. They were not as fast as my 4 blade over the hub cleavers. Regarding Mercury props I have not found a set that would out perform Dewalds.
Tough call on the round ears. Gary had some 6 blades on the 32' wide body skater and the boat ran good. Also KAP ran that style I believe when he set the record in the Doug Wright 115mph. If you order them you had better get 4 ventilator holes in them. I have a little trouble with my 29 Herrings that are 4 blades with 2 holes in them getting the motors to come alive for the first 5 seconds or so. I have run 104 with them 1/2 tank fuel. They are great at slow speeds no slippage. |
Good info Ron, Thanks!!! Really would like to be able to run at lower rpms without the high prop slip. Sounds like Something Sam really has no need for huh LOL... wonder how the herrings do on that?
Sam, I'll try and get with you today...at least by middle of next week... hopefully have some kinda lowers back on one way or another by then LOL. |
Originally Posted by Maritime_Eng
(Post 4128858)
On my 30 DW I am running 14.50" X 32p 5 Blade Thru Hub/ Cleaver Tip props. Runs 107 @ 6100 rpm.
I had a set of Dewald 14.25 x 33p 5 Blade Thru Hub Cleavers and ran 108 @ 6150 RPM . Don, Can you take a pic of your prop and share here, just to be sure we have the right style image of the thru-hub cleavers. How much does your prop cost each? |
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Uh oh, new pricing structure for the race-style cleavers. the price I quoted [$3,600] was for round-ear Herings http://i1238.photobucket.com/albums/...s-page-img.jpg |
You have the right picture. But instead of the round ear mine are pointy tip (cleaver style).
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Originally Posted by Maritime_Eng
(Post 4130786)
You have the right picture. But instead of the round ear mine are pointy tip (cleaver style).
Don, What is the gear ratio of your lowers? . |
Originally Posted by noli
(Post 4130931)
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Don, What is the gear ratio of your lowers? . |
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Need some pics to add to the BS Thread! Motivation for all you guys up north....
FL Keys a couple of weekends ago. |
Originally Posted by Double Rigged
(Post 4133020)
Need some pics to add to the BS Thread! Motivation for all you guys up north....
FL Keys a couple of weekends ago. |
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