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-   -   34 yellowfin w/ twin mercury Verado 400ís (https://www.thehulltruth.com/boating-forum/994780-34-yellowfin-w-twin-mercury-verado-400-s.html)

Turtle208 03-17-2019 11:12 AM

34 yellowfin w/ twin mercury Verado 400ís
 
Would anybody have performance numbers for. 34 yellowfin with 400 Verados? Not the 400rís, just the regular 400ís.

Boatsareawesome 03-17-2019 11:37 AM


Originally Posted by Turtle208 (Post 12343834)
Would anybody have performance numbers for. 34 yellowfin with 400 Verados? Not the 400rís, just the regular 400ís.

Would be almost identical to the 400r performance. 6800rpm in the production 400 versus 7000rpm with the R. That would not be the ideal twin setup for that boat. The only difference in the 350, 400, and 400r is the calibration (6400, 6800, 7000 WOT respectively) so unless you plan on running everywhere at 6600+ rpm, you wonít see any real gains over 350s.

captbone 03-17-2019 11:37 AM

The performance numbers I have see put the 400M within 1mph of the 400R.


Turtle208 03-17-2019 12:15 PM

I do long canyon runs full of fuel and gear and currently have twin Yamaha f250...needless to say it struggles to get out the hole...looking to repower with twins...what would you all recommend

FlyfisherJHR 03-17-2019 12:38 PM


Originally Posted by Turtle208 (Post 12343972)
I do long canyon runs full of fuel and gear and currently have twin Yamaha f250...needless to say it struggles to get out the hole...looking to repower with twins...what would you all recommend

I have run that exact boat for 8 years with twin F350s and it performs very well. The YF34 was originally designed around that twin F350 platform. As you probably know, though, that motor has had problems, but I don't know if the more recent generations have had the same issues as the early ones. I would prob not go twin Vrod 350s b/c not enough mid-range torque (small displacement supercharged engine). Can you do trips or needs to be twins?

Boatsareawesome 03-17-2019 12:39 PM


Originally Posted by Turtle208 (Post 12343972)
I do long canyon runs full of fuel and gear and currently have twin Yamaha f250...needless to say it struggles to get out the hole...looking to repower with twins...what would you all recommend

Yamaha 425s (if you can get them)
Suzuki 350 duo props (if you have local service support)
Mercury 400 production motors (would be my last choice, and I am a Mercury guy)

Note: Yamaha 350s are going away soon. I wouldnít buy them because of a number of known and documented issues.

davidwademarine 03-17-2019 12:45 PM

I, along with our customer, was very surprised with the ability of triple 400R Verados to replace triple Yamaha 350s on a 42 Yellowfin repower. He gained performance all the way around (holeshot thru top end) and picked up considerable fuel economy. If youíre currently rigged with twin Yamaha 250s, I think twin 400s would be a great fit. Iíd opt for the standard production 400 Verado that was released at the Miami Boat Show. If youíre satisfied with the top end performance now then a set of new V8 Verado 300s would be a good choice too, if you can get your hands on any.

syrupdawg 03-17-2019 02:23 PM


Originally Posted by davidwademarine (Post 12344049)
I, along with our customer, was very surprised with the ability of triple 400R Verados to replace triple Yamaha 350s on a 42 Yellowfin repower. He gained performance all the way around (holeshot thru top end) and picked up considerable fuel economy. If youíre currently rigged with twin Yamaha 250s, I think twin 400s would be a great fit. Iíd opt for the standard production 400 Verado that was released at the Miami Boat Show. If youíre satisfied with the top end performance now then a set of new V8 Verado 300s would be a good choice too, if you can get your hands on any.

I'm waiting to hear about the fuel burn difference in the new 300 v8 versus the 350 verado. I'm not overly concerned with top speed but fuel burn and ability to push a heavy load in my 33' twin engine application is at the top of the list.

Seasir 03-17-2019 02:40 PM

I’d look hard at suzuki 350’s. I went from F350’s to the Suzuki’s on a 33t contender and saw improvement on the hole shot, handling, top end and economy. I load very heavy and make 150+ mile runs into the gulf, that pushed me towards the Suzuki’s over Mercury’s to handle the heavy loads. I was coming out of F350’s after a couple of failures that were common with the motors, no way would I ever consider another set of those.

Godspeed 03-17-2019 03:33 PM


Originally Posted by FlyfisherJHR (Post 12344024)
I have run that exact boat for 8 years with twin F350s and it performs very well. The YF34 was originally designed around that twin F350 platform. As you probably know, though, that motor has had problems, but I don't know if the more recent generations have had the same issues as the early ones. I would prob not go twin Vrod 350s b/c not enough mid-range torque (small displacement supercharged engine). Can you do trips or needs to be twins?

The 34 wasn't designed around the 350

MajSchaefer 03-17-2019 04:35 PM


Originally Posted by syrupdawg (Post 12344289)
I'm waiting to hear about the fuel burn difference in the new 300 v8 versus the 350 verado. I'm not overly concerned with top speed but fuel burn and ability to push a heavy load in my 33' twin engine application is at the top of the list.

Typically, Scout or BW have performance reports between the new 300s and Verado 350s.

Ris-K 03-18-2019 11:25 AM

Turtle- welcome to the THT. The common theme around this place is max HP is always needed and it takes a dually to pull a bay boat. I ran a 36 Yellowfin with twin yami 350's. Boat light was a 60 mph boat and had solid fuel economy. 1.3 if I recall. I would suggest twin 400's would run a 34 great.

Before someone else says it, a triple powered 34 regardless of brand will get you on plane if you lose a motor.

This is a good read for comparison

https://www.sportfishingmag.com/boat...s/yellowfin-34

avid lurker 03-18-2019 12:08 PM

Does anyone have any performance numbers for a 34 with twin 350 Verados vs the 350 Suzuki?

avid lurker 05-13-2019 07:12 PM

Finally finished with the repower on my 34. Went from yamaha 250's to the new 400 Verados. It is a completely different boat!!

Here are the initial performance numbers:

3 men on board w/ 270 gal of fuel
Rev 21's

10 seconds to plane

38.8MPH at 3800 1.54 MPG
41.5MPH at 4300rpm 1.64 MPG
59.1 MPH at 6300 .88 MPG(WOT)

Still have a little tweaking to do.

Ken T 05-13-2019 08:01 PM


Originally Posted by Turtle208 (Post 12343972)
I do long canyon runs full of fuel and gear and currently have twin Yamaha f250...needless to say it struggles to get out the hole...looking to repower with twins...what would you all recommend

Is anything wrong with your 250s ? If not, I'd just slid them over a bit and add 1 more. Run them another couple thousand hours and see what power options are out there.

floffshore 05-14-2019 10:25 AM

i think one of his main goals was fuel burn and adding a third motor would probably hurt that considerably

dnh2 05-14-2019 10:27 AM

I would just put any new Merc motor on your boat and you will never need fuel again, nor have to service your boat, and you will be able to sell your boat for as much as a Freeman and buy a new boat for free, according to the average THT thread.

Ken T 05-14-2019 10:46 AM


Originally Posted by floffshore (Post 12526028)
i think one of his main goals was fuel burn and adding a third motor would probably hurt that considerably

I must have missed the part from OP about fuel burn

floffshore 05-14-2019 11:16 AM


Originally Posted by Ken T (Post 12526106)
I must have missed the part from OP about fuel burn

i think you're right.. i may have inferred that somehow.. i could be wrong

pas 05-14-2019 02:31 PM


Originally Posted by avid lurker (Post 12524073)
Finally finished with the repower on my 34. Went from yamaha 250's to the new 400 Verados. It is a completely different boat!!

Here are the initial performance numbers:

3 men on board w/ 270 gal of fuel
Rev 21's

10 seconds to plane

38.8MPH at 3800 1.54 MPG
41.5MPH at 4300rpm 1.64 MPG
59.1 MPH at 6300 .88 MPG(WOT)

Still have a little tweaking to do.

As part of your tweaking you should try some Eco Enertia props, 18-19's maybe? I have tried 20 something sets of props on my boat and these gave very good performance all around and the best mpg I have ever gotten.


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