Yamaha 300 V-6 vs 350 V-8

[Capt. Ed]

I'm getting ready to order a new 255 and would appreciate any thoughts on which motor to go with. I'm especially interested in reliability of the 350 and any problems you may have had. I've only heard good things about the 300 so far.

thanks,

 

[Tucker]

See 300's all over the place up my way but have not seen any 350's. Not sure of the reliability but huge weight difference. The 350 is a V8 and weighs in at about 800 Lbs. The 300 is a V6 and weighs about 560 lbs.

 

[Tucker]

See 300's all over the place up my way but have not seen any 350's. Not sure of the reliability but huge weight difference. The 350 is a V8 and weighs in at about 800 Lbs. The 300 is a V6 and weighs about 560 lbs.

 

[Tashmoo]

I have an F 350 on my 2008 Tournament 275. The engine has 650 hours on it, has been flawless and is a perfect match for the 275. For a 255, I would say that the tradeoff of weight to additional horse power and torque for the 255 would not be worth it. I was skeptical about the 300 at first given all the new technology but given the good feedback on the 300 it appears to be a winner and a very good complement for the 255.

 

[NOTHING ELSE MATTERS]

I also have a pair of F350's with no problems, but i have to agree with Tashmoo, for the 255 the F300 will work as good as the F350 with a lot more savings.

 

[Capt. Ed]

Thanks for the replies! I would normally agree with comments about weight and fuel economy, but when I look at performance tests on Grady's website, the 255's sister ships, the 257 and 258 all get better mileage and speed with the 350hp when the tested weight is similar. For the 275, the v-8 gets better results than twin 150's. Plus, the 350 weighs less than two 150's.

I guess there is no for sure answer.

Thanks again.

 

[Tashmoo]

A bit of techno babble from my perspective on the F350 vs. the new F300. The F350 has a lower break mean effective pressure than the F300 does which translates to less force on the crankshaft and hence bearings which translate maybe into more durability. I like the even firing order of the V8 vs. the uneven firing order of a V6. The way the manufacturer corrects for the uneven firing order is to rotate the crank by 22.5 degrees which results in a point in the crank where there is less meat then on a v8 crank. All of this has been engineered and I am sure there is no loss in durability. That said from my perspective if I can have a stronger engine by design why not. I also had concern about the removal of the cylinder lining in the F300 to gain bore and the use of plasma coating on aluminum to provide the hard surface lost by the removal of the liner. This is technology that has been used in the aircraft industry successfully for years but I have say there is no salt water in an airplane engine. Just my thoughts.

Below you will find a blurb I wrote back in 09 on my engine evaluation.

For what it is worth here are my findings regarding cost to performance after a lot of time and effort. One 350 HP engine was a little more than $3,000 less than twin four stroke 150’s. The single 350 was faster and ca. 80 lbs lighter than 2x150's. With the F350 you get all of the new technology that is not available on the 150's or 200's for that fact such as variable rate valve timing and fly by wire controls. The controls are as of yet unproven so they may prove to be a liability but the variable rate valve time is clearly a plus. My research showed me that one 350 had roughly equal or slightly less performance on the 275 hull to that of 2x200 four strokes for five figures less $$$. I did not look at twin 200 2 strokes as I was informed by my dealer that GW is not offering them on new boats any longer, this may be a load of BS, I do not know. Maintenance is clearly less as you are only dealing with one engine and of course drag is less since there is only one drive in the water. Fuel consumption was better with a single no matter how I looked at it against any twin combination.

 

[Capt. Ed]

Tashmoo, I think I followed all that. What I do know is I sea trialed a 255 with the 300 V-6 yesterday and was disappointed. For me, the V-6 worked a little too hard to plane off and to keep the boat on plane at low cruising speeds. I'm more of a power freak so this is not meant as a criticism of the V-6. I'm sure it more than meets the needs of 90% of the buyers of this boat. It's just not my cup of tea.

So, this morning an order went to Grady for a new 255 with the 350 HP V-8. My wife and I are excited and can't wait.
We'll be visiting Greenville to check on it's progress a couple times over the next 4-5 weeks.

 

[NOTHING ELSE MATTERS]

Congrats on the new purchase. I am sure you'll be very happy with the 350. All it comes down i guess is the torque they produce. Good choice.

 

[Tashmoo]

Capt. Ed,

Congratulations on the new purchase. You will be thrilled with the F350 it has been a great engine for my boat and I put a good amount of hours on each year. To put it in perspective, the F350 pushes my 275 at 47 MPH max, gets 2.2 MPG between 26 & 30 MPH is quiet and has more torque than you can imagine. If it does that on a 275 you will be over 50 MPH on the 255 and you better hold on because it's going fly out of the hole.

A couple of things on the F350, gas makes a difference at top end. When I am forced to use 87 octane I lose about 3 MPH off top end. Oil changes are messy, I have yet to find a way to unscrew the filter without dumping a substantial amount of its contents into the engine enclosure. Have lots of rags handy if you change your own oil. Make sure that the F350 will lift all the way out of the water on the 255. This is really important if you are in salt water as there is a lower water pickup on the 350 at the bottom of the torpedo. If it does not come out of the water you will have a mussel farm on your hands and the little bastards are above the inlet screen so it is a free ride to the cooling passages when one breaks lose. I had this issue on the 275 and worked out a solution with GW to get it out of the water but it took a lot to get there.

 

[Capt. Ed]

Thanks Tishmoo for the info. My marina has 90 octane gas with no ethanol so I should be ok.

I'll check on the tilt issue. Do you put bottom paint on your engine? That's common in our area as most Yamaha's I've seen do rest in the water a little.

 

[Tucker]

I wonder why in the world Yamaha doesn't improve the tilt design to lift the engine all the way out of water. Mercs do. My old S225's are in the water with empty tanks. Pisses me right off. :bang

 

[Tashmoo]

Putting bottom paint on the lower unit was Yamaha's solution to the tilt issue, problem is you have to get the paint up inside the lower water pick up inner passages which I was not interested in doing. Again, the F350 unlike most engines has the second water pick up at the lowest point on the engine bullet so if it does not tilt out of the water you have salt water up inside your lower unit cooling passages all the time which is where I found a colony of mussels growing in mine. Thankfully, I found the issue before they broke loose and raised hell with my engine cooling passages.

I can't speak for other models but on the GW 275, the problem with tilt is not Yamaha, it is with GW's transom/engine well design. The Yamaha can tilt more than enough to rise out of the water; problem is what it hits on the way up.

 

[TIERNEY ROSE]

WOW, WHAT A CONVERSATION, I THINK I MADE A MISTAKE, BEING BRAND,BRAND NEW TO BOATING I BOUGHT A NEW 2008 23' GULFSTREAM AND WHEN ASKED WHAT ENGINE I JUST ASSUMED THE BIGGEST WAS THE BEST, BOAT FLIES OUT OF THE WATER NORTHSHORE(CITY ISALND) BUT IS THIS TOTALLY OVERKILL?? ANY COMMENTS APPRECIATED