425 on gradywhite marlin

[frisco]

Does anyone know what the procedure would be to install 425 on my 2008 marlin. I know they are to heavy but would be nice.

 

[efx]

Not enough power. Unless you mean two of them. Honestly get twin 300.

 

[Fishermanbb]

Single or twins? Twins will exceed the HP rating for the boat and the transom will definitely need to be reinforced. New controls and some steering changes as well. Even at that my guess is the boat will sit very low with that much weight on the transom. A single may actually be slightly underpowered and IMO the boat will not ride as well as the beam on that boat pairs better with twins. The 232 is the same problem IMO. It will run fine with a single 250 but runs MUCH better with twin 150’s/200’s. Also, the 30 with a single around the dock will be a bear. IF you are trying to get some speed the 350’s will push that boat about as fast as that hull can safely go (It is NOT a fast hull). If you get 350’s try to find some good used “C” series (2016 and later). Also, twin 300’s run the boat nicely.

 

[SeaVee]

There was an older Marlin for sale a while back and it had been repowered with twin 425’s Think it was in MD. Have you seen one of those motors in person?
There are huge.

 

[frisco]

That was in Connecticut marlin with twinn 425. We'll just wait and see maybe yamaha will come back with 350 again I love my 350s pushes the marlin just very nicely

 

[amf282]

Go with twin 350 zukes.....we went with twin 300's on our 282 and they have performed beautifully. Handles much better than the 250's. Also get better fuel economy.

 

[Fishtales]

Max HP on the latest model is 700. Earlier ones are 600. Why would anyone put a single 425 on it? You'd prob rip the transom off with 850 and have no insurance to boot. Is this question for real??? I agree with above. twin 300s best. Even twin 250s are fine.

 

[SkunkBoat]

don't see the sense in twin 425s on a Marlin. its not a 50mph+ design. 250s were more than fine for all these years.
maybe go 300 but after that it seems like you're compensating for penis size...

 

[Mustang65fbk]

don't see the sense in twin 425s on a Marlin. its not a 50mph+ design. 250s were more than fine for all these years.
maybe go 300 but after that it seems like you're compensating for penis size...

I'd disagree on the 50mph+ design comment. Per the Grady White website in the "Performance Data" section for a 300 Marlin it says that with twin 300 Yamaha's it'll hit 49.5mph @ 5800rpm. I could only imagine that with twin 350's that it would hit the 50mph mark, and then some, maybe even into the mid 50's mph. If hitting 50mph+ is something you wish to accomplish and your wallet can take the hit of $30k+ per brand new motor, then by all means go for it. I take that back, go for it in 18 months when the motors will be available from Yamaha, that is.

I do agree with your last statement though about one's particular size... I've never been one to need to go much above 35-40mph when on the water for fear of getting to close to and/or hitting a log, wildlife or so on. It takes a good deal of distance to safely slow down and/or stop when on the water and especially when you're doing 50mph+, and I simply don't have to go that fast. Nor do I want to pay the ridiculous amount of money for a boat and/or motors to get me to that speed, and I certainly don't want to imagine the amount of fuel burned while going 50mph+ for any extended period of time. Aka 52.3gph burned while at those speeds, and I don't know about where you're at but here in Seattle gas is already above $4/gal. I can't imagine this spring and summer that it's going to magically go back down at all.

To the OP, the maximum horsepower rating for your boat is 700hp, per the Grady White website. Not sure that I'd want to go above that for any reason, and as stated above, it certainly wouldn't have to be for my desire to go fast on the water. It's your boat, do what you think will work best for you and your particular situation. I like Suzuki outboards for their lower pricing, better warranty and a handful of other reasons, so if/when I go to re-power it'll be with Suzuki. Lastly, those Yamaha 425's also weigh 1k lbs a piece, which if you had two of them then that would be over 2k lbs in weight just for outboards. I think I'd go for the weight savings and get something a bit lighter like 350's or something else.

 

[SkunkBoat]

I'd disagree on the 50mph+ design comment. Per the Grady White website in the "Performance Data" section for a 300 Marlin it says that with twin 300 Yamaha's it'll hit 49.5mph @ 5800rpm.

not a matter of if it will "hit 50mph". The boat is too tall and the helm to high and fwd to comfortably/safely ride that fast in anything but glassy calm with no chance of boat wakes.
Its not made to do 50. Its not that kind of boat. They have Canyons for that.

 

[Mustang65fbk]

not a matter of if it will "hit 50mph". The boat is too tall and the helm to high and fwd to comfortably/safely ride that fast in anything but glassy calm with no chance of boat wakes.
Its not made to do 50. Its not that kind of boat. They have Canyons for that.

Could that not be said about most boats under 30' in length though? Especially in regards to a walk-around? Any boat will do just fine when it's flat as glass out on the water, conversely I don't think I'd want to hit a decent sized wake at 50mph in most boats, maybe even in Canyon? I admittedly don't know very much about the larger Grady's, that being said I don't need to go 50mph even in perfect conditions, not to mention going 50mph over another boats wake. Being able to claim you can do that makes me ponder on your "size" comment from earlier. Regardless... back to the topic at hand *drum roll*

 

[Fishtales]

Reminds me of a saying (in context) that my dad would say. Just because you can (over power the transom and push a boat to speeds that don't mesh with the design) doesn't mean you should.

 

[ElyseM]

other than hull rating issue, those things are big. 33 in the slip next to me has them and they are huge sitting on that transom. i'm running the new 300's and they're more than enough for the boat. JMHO. good luck, ron

 

[blindmullet]

Reminds me of a saying (in context) that my dad would say. Just because you can (over power the transom and push a boat to speeds that don't mesh with the design) doesn't mean you should.

Yep! These boats are slow pigs...just go with it. Lol

 

[magicalbill]

I would seriously try to find a pair of 350's, Series #C as Fishermanabb said. That's the best power combo for the Marlin, as far as I'm concerned.

My guess is 425's while a cool idea, would make it stern-heavy and cause it to porpoise on plane.

I've had my Marlin to 50MPH in calm water and it's rock-solid. There is certainly no reason to run 'em that fast in any kind of sea. I haven't opened it up yet, but I'm certain it will do 52-53, although I would be burning fuel like a 747 talking off.

 

[Fishtales]

Also if you go big, expect heavier and then the scupper thru hulls may be in the water. I agree 350s, 300s or 250s in that order. I have the latter and it is more than enough power.

 

[frisco]

We currently have twins 350 Yamahas on it now and they push that 12000lb boat 50- 55 n miles buitifully back to that other comment, definitely no viagra here.

 

[frisco]

It's just to bad yamaha is not coming back with 350 they are very nice engines when they are taking care of. Thanks for posting

 

[Angler Management]

My twin 300 V-8 Verados are plenty. I'd seriously worry about overstressing the transom with the twin 425, and if you were talking single it will be too small. As for how to install, just hook em up as normal.

 

[frisco]

My twin 300 V-8 Verados are plenty. I'd seriously worry about overstressing the transom with the twin 425, and if you were talking single it will be too small. As for how to install, just hook em up as normal.

I was just wondering if anyone other than the person in Connecticut had done this. I know the marlin is not capable of anything over 350s transom is not strong enough. Hull not rated for 60mph and etcetera. When theses engines grenade I'll put 350s back on . The boat with 350s planes out the boat buitifully with easy. Anyways thanks for responding .