Marlin cruising speed and economy

[Jrspawn]

Just wanted to get some feedback from the group of what the best overall cruising speeds, RPM, and economy has been in your Marlin 300's? I have an 01 with the OX66 250's and I am curious if I've found the best RPM/speed/economy numbers yet. Thank you

 

[seasick]

Those motors are not particularly fuel efficient. My guess is that the most 'efficient' spot is in the 3600 to 4200 range but that's only a guess. There are many factors that will affect your numbers.

 

[Fishtales]

I find 4000 rpm, 1.2 or slightly more gal/hr forget speed. Usually run in the 3800 to 4400 range. Yamaha F250s.

 

[jmain]

I have been playing with this a lot lately. According to my Garmin’s, I can generally get 1.5 mpg (and that is statute miles per gallon) somewhere between 3700 and 4400, depending on the wind and the waves. If it is really calm or there is a slight tail wind, I can get it up to 1.6.
The conditions make a lot of difference, so you’ll just have to play with it. The slower I am going, the closer my trim is to “2”. The closer to 4400 I get, the closer I get the trim to “3”. Having the trim too high cuts efficiency very quickly, I thought it would be the opposite.
I always have the trim tabs all the way up. Your props can make a big difference too. My setup isn’t exactly the same, but it is close. We have 2006 F250s on a ‘96 Marlin 30.

 

[g0tagrip]

I have an 07 Marlin with F250s: My best long range cruise is at 4100 RPM, roughly 29 mph and 1.3mpg. Of course it is all sea dependent and where I have the trim tabs set.

 

[family affair]

What seasick says for fuel economy on an ox66 is correct. 4 strokes have different gearing and have a higher RPM sweet spot.

 

[BirdRock]

Anyone running twin Yamaha 350’s on their Marlin? Just went into contract on 2009 with 350’s. Boat in awesome condition but I’m worried the ideal cruising rpm with these engines will be in the death zone for the flywheel issue. I think the problem rom range is 3200-4200 or thereabouts. I’m not worried about trolling hours as that will be well below 3200 but thinking the best cruising speed will be in they range.

survey and sea trial soon so I’ll know then. Just curious if anyone else has this set up.

 

[Mustang65fbk]

Anyone running twin Yamaha 350’s on their Marlin? Just went into contract on 2009 with 350’s. Boat in awesome condition but I’m worried the ideal cruising rpm with these engines will be in the death zone for the flywheel issue. I think the problem rom range is 3200-4200 or thereabouts. I’m not worried about trolling hours as that will be well below 3200 but thinking the best cruising speed will be in they range.

survey and sea trial soon so I’ll know then. Just curious if anyone else has this set up.

I'm not sure why they don't have it on the main Grady White website but if you go to the attached link it has the "performance data" for a brand new 300 Marlin with twin 350 Yamaha's on it. I'm sure there will be some slight differences and that the test numbers obtained were in near perfect conditions... that being said, it should give you some ballpark numbers.

• Engine Size: 5.3L
• Test Date: 04/03/2007
• Prop Size*: 15 1/2" X 19 SWS XL SDS
• Weight as Tested: 12,507 lbs. (including persons, fuel, water, gear, engines & accessories)
• Hardtop: Yes
• Bow Pulpit: Yes
• Bottom Paint: No
• Optimum Cruise: 31.5 MPH @ 3500 RPM

* This report should be used only as a general reference guide. All performance data, including speeds, fuel consumption and range, is estimated and not guaranteed. Actual performance may vary. Boat performance may be impacted by many factors including, but not limited to: loaded displacement, boat configuration and options, trim, sea conditions, climate, hull bottom, surface condition and mechanical systems condition.

RPM	MPH	GPH	MPG
1000	6.2	2.7	2.28
1500	8.5	5.2	1.64
2000	9.6	9.5	1.01
2500	14.2	13.2	1.08
3000	22.9	16.9	1.36
3500	31.5	21.5	1.47
4000	37.1	28.8	1.29
4500	42.2	35.2	1.2
5000	46.2	45.9	1.01
5500	52.2	59.9	0.87
5900	56.8	67.6	0.84

Grady-White Marlin 300

Explore the Grady-White Marlin 300 for sale in Longboat Key, FL, and embark on your next fishing adventure with a top-tier sport fishing vessel. Find the perfect blend of performance and luxury on the water. Contact Cannons Marina today!

cannons.com

 

[magicalbill]

Anyone running twin Yamaha 350’s on their Marlin? Just went into contract on 2009 with 350’s. Boat in awesome condition but I’m worried the ideal cruising rpm with these engines will be in the death zone for the flywheel issue. I think the problem rom range is 3200-4200 or thereabouts. I’m not worried about trolling hours as that will be well below 3200 but thinking the best cruising speed will be in they range.

survey and sea trial soon so I’ll know then. Just curious if anyone else has this set up.

I am.

First the numbers. They are undeniably great:

35MPH at 3900 RPM 1.4 MPG
36MPH at 4000 RPM 1;3-1.4 MPG
38-39MPH at 4200 RPM. 1.2-1.3 MPG.

Yes, these are in the Kill Zone for the flywheel harmonic problem. I said "screw it" and still say that. The Yamaha info center send up an alert when the wheels need to be changed. I eat a grouper sandwich at the next-door food joint and in an hour or so, it's done. No big deal.

Remember, it takes longer than you think to rack up 80 hrs within the 3500-4300 range that affects the wheels. Factor in idle time, manatee zones (in SW Fla) and any trolling you do and it could be a couple years before you have the issue. I try to combine it with a service at the same time.

I am a Loud Spoken Advocate of the newer 350's, especially on a Marlin. I think there is no better combo. That said, if you have the early versions of the 350's, they have a history of problems which has, unfortunately, tainted their reputation. I own the 350C's which are 2018's, and they've been flawless. I would certainly have a reputable tech make sure they're reliable before firing the gun on your boat. As much as I love my new ones, I would be concerned about the older models.

There. Full Disclosure.

 

[BirdRock]

Many thanks magicbill. Unfortunately I’m looking at a boat with the first generation 350s. Got my yahama mechanic set for inspection and am well aware of the issues on the early models. Plan on proceeding unless something terribly wrong shows up. Planning to repower when needed.