2006 330 Express 1200 hours on Yamaha 250's. Considering upgrade / repower with either 300 or 350 Yamahas. XSA. forums say check with G/W for blessing. Hull is rated for 850 hp. obviously i will check integrity of the transom prior to anything being done. But if the transom is bad ... the transom is bad ... wouldn't matter if it was 200's 225's etc. If the hull is rated for 850 hp why the concern for a total of 700hp ? These are NOT the V8's but the new V6's. Fill me in please . Thanks in advance.
f300's or f350's
- Thread starter Danos express
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The 2006 (and 2007 330 express hull that I have), is rated for a maximum of 600 hp according to the specifications in the owners manual. That manual is available online at the Grady-White website. I re-powered my boat with 300s and have been very pleased with the increased performance as opposed to the older 250s.I have not seen a higher rating for the 2006 and wonder where that number was derived from. I am certain you will not get a blessing from Grady-White to put anything higher than 600 hp on that hull.
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05 250……… 605 lbs (what I have now)
26 300……….550 lbs ( what I can get)
26 350 V6….630 lbs (what I really want)
A total of 50 extra lbs on the ransom and 200 more hp
Or
Lose 100 lbs and gain 100 hp
I understand the express is no speed demon … but the advantage of lower rpms for the same SOG and better mpg really makes me lean towards that. Is 50 more lbs on the trans one that much of a big deal ? I get it … TORQUE .. that’s an issue as well … but I’m not looking for holeshot either … just looking for some other opinion on this.
26 300……….550 lbs ( what I can get)
26 350 V6….630 lbs (what I really want)
A total of 50 extra lbs on the ransom and 200 more hp
Or
Lose 100 lbs and gain 100 hp
I understand the express is no speed demon … but the advantage of lower rpms for the same SOG and better mpg really makes me lean towards that. Is 50 more lbs on the trans one that much of a big deal ? I get it … TORQUE .. that’s an issue as well … but I’m not looking for holeshot either … just looking for some other opinion on this.
You are correct and it is probably safe. If your insurance company doesn’t have an issue, I don’t think the engines are gonna fall off or sink the boat unless of course the transom is bad. And like you say if the transom is bad, it’s bad! If you are going forward with this, recommend you look at the performance bulletins that Grady provides for the 250s versus the 300s versus the 350s. They are all available on the Grady website and in my. Experience are really pretty accurate. I think given the difference in efficiency, ie. fuel consumption, you will likely not ever recover your re-powering costs. If reliability is very important, the 300s have a long proven history and are bulletproof. The 250s were also bulletproof except for the mid. Section corrosion issues in the earlier engines. The newer 350s appeared to be very reliable, but their history is relatively short, particularly for the V6. With regard to RPMs, I know the 300s and the 250s have different gearbox ratios so the actual propeller RPM is different and requires a different sized propeller. I had to change Props when repowering to the 300s. Good luck!
Thank you for your insight … taken with consideration. Anyone else please let
Me hear your thoughts
Me hear your thoughts
JJF
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Apples and oranges, but...
My buddy has twin 300s on his Pursuit 325/345 Offshore and it runs very well.
Hope this helps
My buddy has twin 300s on his Pursuit 325/345 Offshore and it runs very well.
Hope this helps
If you are asking on a choice between F300s or earlier (not rev C) F350s my answer would be F300s
teaklejr
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Give Ed Miller from HI Tech marine and see what he thinks. Ed is a great guy and knows Yamaha's well.
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Thanks teak ! I’ll calm him later today.Give Ed Miller from HI Tech marine and see what he thinks. Ed is a great guy and knows Yamaha's well.
Home - Hi-Tech Marine Services
Yamaha outboard repair, 100-hour service, diagnostics, propellers, and performance upgrades for sport and fishing boats. PowerTech! propeller sales and installation. Family-owned since 1998.
What did you find out? I'm considering the exact same questions for a Repower of my 330.
Very good info …
Decent price for install. I am currently revamping my 250’s for sale. Water pump … gear lube… oil … filters etc. I can’t go 350’s as mine is an ‘05… only rated for 600 hp. I have a line on 2 merc V8 300’s with 3 hours on them … owned by a friend of mine in NC. He is replete g his regulator and will seek them to me for what he bought them for plus 3 yr extended warranty. He runs a charter there and gets his motors very reduced $. He doesn’t like the ride with the 300’s.
Decent price for install. I am currently revamping my 250’s for sale. Water pump … gear lube… oil … filters etc. I can’t go 350’s as mine is an ‘05… only rated for 600 hp. I have a line on 2 merc V8 300’s with 3 hours on them … owned by a friend of mine in NC. He is replete g his regulator and will seek them to me for what he bought them for plus 3 yr extended warranty. He runs a charter there and gets his motors very reduced $. He doesn’t like the ride with the 300’s.
Express 360 Finally
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Be mindful of the max hp rating on the 33. I repowered my rig and checked in with the Grady engineers, with my insurance co and 2 others for for a second and 3rd opinion. The grady engineer said I could repower with triple 350s but warned that insurance could deny a claim if the max hp rating was exceeded.
My insurance broker said the same thing. Warning me that exceeding the plate rating could give the insurance company an out to deny a claim should one need to be filed. While unlikely, i wasn't interested in the additional risk. I repowered with 4.2 ltr 250s. My express is 10 tons fully loaded with fuel, gear and crew. I don't need to go 45 mph to get offshore.
My insurance broker said the same thing. Warning me that exceeding the plate rating could give the insurance company an out to deny a claim should one need to be filed. While unlikely, i wasn't interested in the additional risk. I repowered with 4.2 ltr 250s. My express is 10 tons fully loaded with fuel, gear and crew. I don't need to go 45 mph to get offshore.
Yea … thanks for the reply … I’ve opted to stay with the max HP rating and go with 300’s. Not worth the hassle with insurance IF anything might go wrong. And you know how Murphy likes to show up for a cruise at the most in opportune time…
Trip 350’s was green lighted by a Grady engineer ???? REALLY!? Interesting???
Express 360 Finally
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Yes. He said the transoms on the 360s had been designed for heavier engines beginning in 2005 but the engine max at the time was 250. The max hp rating was changed once 300s + plus engines came on line.
I’ve seen plenty of older 360s for sale and on the water repowered with 300s and 350s.
Express 360 Finally
GreatGrady Captain
Yes. I was aware of that from your profile. I was referencing my conversation with the design engineer and my 360. The construction and engineering design of the 330 and the 360 and now the 340, 370 are the same. The only difference are the respective beams and LOAs - which dictates weight distribution and HP limits.
I repowered my 2007 306 Bimini with two Evinrude 300’s G2’s. The installer (who services GW, and sells Merc / Yamaha / Evinrude) told me the issue isn’t the HP, it’s the weight.
If you are below or at weight, you are fine. Perhaps a pair of twin V12 600hp Mercs would tear the transom apart, but twin 350’s won’t even stress the transom.
If you are using a digital steering system, you also save the weight of the SeaStar hydraulic steering system.
Lastly, the boat isn’t designed to disintegrate at 1211# (605# x 2 + 1#). They are built with AT LEAST a 10% margin, likely closer to a 50% margin.
As far as insurance goes, they didn’t ask a single detail. I told them I installed new motors, and informed them of the new value. My premiums went up by a couple dollars.
I greatly appreciate the info gentlemen. But I have a line on some Very lightly used merc 300 V8’s. Like 3-4 hours light. I’d take your advice and go 350’s but I can’t find comparable prices to beat the mercs… thanks again for the insight
Mustang65fbk
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Older thread here but yes, maximum horsepower per the brochure is 600 hp. Several different options for 300's out there from Yamaha to Suzuki, Mercury, Honda and more. Mercury would be the lightest at 527 lbs for their 300 FourStroke series, then the Yamaha F300 at 551 lbs, the Honda M300 at 622 lbs and then finally the Suzuki DF300 at 639 lbs. Ideally, and it sounds like you've already gone this route, would be the Mercury's as they're 75 lbs lighter per outboard, have a 5 year warranty, are a v8 and likely have better torque that the v6 will. Yamaha is likely going to be the most expensive, only have a 3 year warranty, etc. The Honda looks like it's made by Honda/McLaren and comes with a 5 year warranty as well. Suzuki will likely be the cheapest option for a new repower, though it's going to be about 40 lbs heavier per outboard, and they're also running a 7 year warranty promotion right now. Someone mentioned above that the maximum horsepower rating is more of a weight issue than it is being an issue of horsepower. I'm not sure if that's true or not, and can't imagine than an extra 30 lbs per outboard, or 60 lbs total, for a brand new pair of Yamaha F350's would be the difference between there being an issue and there not being one. Suzuki seems like they always have a 5 year warranty and oftentimes run a 7 year warranty, and it seems like they're always matching or competing with Mercury in terms of warranties/promotions, and vice versa. Of which, with Suzuki typically having the lowest prices... that would likely make them be my first choice for if/when I ever went to repower my own boat. Good luck!