Thinking of replacing my Yamaha 250 with a 300 or 350? Boat is a 2007 Gulfstream and I have received good and bad about both engines. Can any present operators of either engine tell me what they think about their boats performance. One Dealer is telling me the 350 is two heavy and puts the engine in the water flow when backing off or in a following sea. Also commented the boat he put one on now has the scuppers in the water. Another Dealersaid the 350 was better because of the extra HP and better fuel ecomony running at lower rpms for the same speed. Would appreciate owner experiences.
Repower 2007 Gulfstream Yamaha 300 vs 350
- Thread starter Bates
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wahoo33417
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Bob: Hard to imagine that a boat most commonly sold with a pair of F150s would have a weight problem with an F350. However, I think Grady will tell you that your bracket was no designed to take that much horsepower and torque on a single engine mount. If that is a concern, you could consider the new, 6 cylinder F300. I just repowered with one (35 hours so far) and it has noticeably more power than the F250 it replaced.
Last year we test drove a new '09 with an F350 on it and didn't notice any problem w/the scuppers or the weight of the engine. Maybe the newer models have a bracket/transom designed to carry the 800+ lbs. Engine performed great, really got her up on plane effortlessly and top speed was over 50 mph. If that's an option for you and your dealer will install it, I would go for it. Only downfall is docking with one engine - can prove to be difficult with such a 'beamy' boat.
Check with your dealer to see if they know about adding floatation to your bracket. We considered putting an 350 on our 2000 two years ago and they said that was an option (I think they add some type of styra foam-like substance to the underside). After they contacted Grady White, however, GW said they would not give them permission to put the F350 on an older hull. Too much torque for the transom. As mentioned before, I would think the reduction in weight in the F300 would be the next best option. Good luck
Check with your dealer to see if they know about adding floatation to your bracket. We considered putting an 350 on our 2000 two years ago and they said that was an option (I think they add some type of styra foam-like substance to the underside). After they contacted Grady White, however, GW said they would not give them permission to put the F350 on an older hull. Too much torque for the transom. As mentioned before, I would think the reduction in weight in the F300 would be the next best option. Good luck
Before you go to far with this idea, you better contact Grady and give them the serial number for your boat. Grady put out a notice to dealers a few years ago to NOT MOUNT a 350 on any boat newer then 2008. It has to do with the strength of the transom. Why not just go to a pair of 150's --- Far more economical and allows you to troll on 1 engine instead of that 350HP monster.
I have an '07 with twin 200 4-strokes that I ordered from the factory. They have to be heavier than a 350 and the twins are a perfect match for my 232.
My scuppers are mostly submerged an it doesn't matter in the least. The boat drains fine and has for the 3+ years I've had it.
I would go with the 350 or twin 150's or (preferably) 200's unless an authority on the matter says otherwise.
My scuppers are mostly submerged an it doesn't matter in the least. The boat drains fine and has for the 3+ years I've had it.
I would go with the 350 or twin 150's or (preferably) 200's unless an authority on the matter says otherwise.
Sorry --- That's what I was told by a Grady-White rep --- If you find out otherwise -- Let us know PLEASE.
I was told it is a torque issue, not weight!
I was told it is a torque issue, not weight!
Hey grady23..
The torque thing may be a problem. I had not thought of that.
As we said, best get it from the experts before that kind of money and installation time is spent.
The torque thing may be a problem. I had not thought of that.
As we said, best get it from the experts before that kind of money and installation time is spent.
Repower 2007 Gulfstream Yamaha 300 vs 350
I have an F 350 on my 275 Tournament and now have 500 hours on the engine. The engine does not overload the transom, it does not put the scuppers underwater even with a full tank and a loaded boat and it does not plow when backing down any more than any other engine on a transom that is flat going backwards does.
The engine has been perfect so far, not a single problem to report and its performance is fantastic. Mileage at cruse on my boat is 2.2 MPG in real conditions loaded and fueled.
As for my personal opinion, once you confirm with GW that your boat can accept this engine and confirm that this engine on your model sits OK in the water then I would consider the following.
The F350 is now going into its fifth season and has so far proven itself to be a very durable engine. The F300 is starting its first full season this year and not much long term data is out there yet. I am skeptical about the F300 for the following reason.
As I understand it, the F300 obtains its displacement by removing the cylinder sleeves and employs some type of surface hardening process on the cylinder walls of the raw block. OK, how is that going to hold up in a saltwater marine application five years from now? I know it has been used in aircraft for ever. Problem for me is that aircraft engines are among the most attended to of any engine with strict maintenance and inspections requirements and again no salt water. The guys on my dock don't even bother to fresh water rinse their engines when they pull in. My point is this is not a good comparison of applications.
The F300 uses a lot of new technology to reduce weight and increase performance. That is, Yamaha had to push the limits of this block series beyond what it has previously done and the engine has little history as of this point. It might be a great engine, I don’t know, but it might be another 300HPDI. Yes, Yamaha does screw up every now and then. The other thing to think about is that the F350 was Yamaha’s first venture into large displacement high horsepower outboards and they over designed the hell out of the F-350 so as not to enter the market with a dog. Ok so it is 50 pound overweight, big deal! The F300 is their attempt to lighten up now that they have proven themselves in the market. That means design optimization and pushing the component design factor of safety down towards the lower accepted design limits. Sometime you over shoot and miss something.
The F300 will most likely be a smash hit and ultimately replace the F350’s market position but if I were you I would wait another year for the performance results to come in.
Food for thought!
PS I bought my F350 at the same point in the engines life cycle as you are considering with the F300. It was a roll of the dice, the six year engine warranty was the reason that I took the chance back in December of 07 when I bought.
I have an F 350 on my 275 Tournament and now have 500 hours on the engine. The engine does not overload the transom, it does not put the scuppers underwater even with a full tank and a loaded boat and it does not plow when backing down any more than any other engine on a transom that is flat going backwards does.
The engine has been perfect so far, not a single problem to report and its performance is fantastic. Mileage at cruse on my boat is 2.2 MPG in real conditions loaded and fueled.
As for my personal opinion, once you confirm with GW that your boat can accept this engine and confirm that this engine on your model sits OK in the water then I would consider the following.
The F350 is now going into its fifth season and has so far proven itself to be a very durable engine. The F300 is starting its first full season this year and not much long term data is out there yet. I am skeptical about the F300 for the following reason.
As I understand it, the F300 obtains its displacement by removing the cylinder sleeves and employs some type of surface hardening process on the cylinder walls of the raw block. OK, how is that going to hold up in a saltwater marine application five years from now? I know it has been used in aircraft for ever. Problem for me is that aircraft engines are among the most attended to of any engine with strict maintenance and inspections requirements and again no salt water. The guys on my dock don't even bother to fresh water rinse their engines when they pull in. My point is this is not a good comparison of applications.
The F300 uses a lot of new technology to reduce weight and increase performance. That is, Yamaha had to push the limits of this block series beyond what it has previously done and the engine has little history as of this point. It might be a great engine, I don’t know, but it might be another 300HPDI. Yes, Yamaha does screw up every now and then. The other thing to think about is that the F350 was Yamaha’s first venture into large displacement high horsepower outboards and they over designed the hell out of the F-350 so as not to enter the market with a dog. Ok so it is 50 pound overweight, big deal! The F300 is their attempt to lighten up now that they have proven themselves in the market. That means design optimization and pushing the component design factor of safety down towards the lower accepted design limits. Sometime you over shoot and miss something.
The F300 will most likely be a smash hit and ultimately replace the F350’s market position but if I were you I would wait another year for the performance results to come in.
Food for thought!
PS I bought my F350 at the same point in the engines life cycle as you are considering with the F300. It was a roll of the dice, the six year engine warranty was the reason that I took the chance back in December of 07 when I bought.
Bates, if you go with the new V6 300, it's the easiest, lowest cost, and existing drive will work fine.
Dropping the hammer on one F350 in a hole shot is no way more force than doing the same on twin F200s as Grady offered in twin setup, and twin F200s are hundreds of pounds heavier than one F350.
The problem of the V8 is not torque nor weight since it weighs less than twins and less HP total than the Gulfstream in twin option.
The problem is a standard drive for a single motor does not span the transom as the twin drive does.
The motor's small motor brackets transfer the forces to the larger Grady Drive in turn transfers the forces to the much larger boat transom where it meets the hull on three sides to push and pull it. The larger the drive span the better.
Since you would need a new drive anyway for the V8 since it's a 6 bolter and has a wider bolt pattern, you have to get a single motor drive manufactured that angles out onto the transom footprint similar as the grady twin drive does. The setback may be more since the V8 is taller, however the gear case still probably will be partially submerged anyway. Most drive manufactures custom design each unit, forget going to the Grady dealer for it. There are several who make drives who you can discuss that with. They run programs to calculate the forces and loading as I would expect.
It is not practical to consider modifying the transom and hull attachment glass layup schedule in a retrofit, in new it is easy.
Like with twin F200 option, the aux gas tank gets nixed or not used if you have one. But if the setback is the same as the Gradydrive for twin F200s, the loading will be way less for a F350 perhaps making the aux tank usable if you have one. And no added stress on the boat hull. Realizing twin F200s are likely counter-rotating, I don't recall seeing counters as a requirement on the boat. Two RH motors will apply more torque than two counters. Counters cancel each other's effect at the common bolting surface.
Good luck.
Dropping the hammer on one F350 in a hole shot is no way more force than doing the same on twin F200s as Grady offered in twin setup, and twin F200s are hundreds of pounds heavier than one F350.
The problem of the V8 is not torque nor weight since it weighs less than twins and less HP total than the Gulfstream in twin option.
The problem is a standard drive for a single motor does not span the transom as the twin drive does.
The motor's small motor brackets transfer the forces to the larger Grady Drive in turn transfers the forces to the much larger boat transom where it meets the hull on three sides to push and pull it. The larger the drive span the better.
Since you would need a new drive anyway for the V8 since it's a 6 bolter and has a wider bolt pattern, you have to get a single motor drive manufactured that angles out onto the transom footprint similar as the grady twin drive does. The setback may be more since the V8 is taller, however the gear case still probably will be partially submerged anyway. Most drive manufactures custom design each unit, forget going to the Grady dealer for it. There are several who make drives who you can discuss that with. They run programs to calculate the forces and loading as I would expect.
It is not practical to consider modifying the transom and hull attachment glass layup schedule in a retrofit, in new it is easy.
Like with twin F200 option, the aux gas tank gets nixed or not used if you have one. But if the setback is the same as the Gradydrive for twin F200s, the loading will be way less for a F350 perhaps making the aux tank usable if you have one. And no added stress on the boat hull. Realizing twin F200s are likely counter-rotating, I don't recall seeing counters as a requirement on the boat. Two RH motors will apply more torque than two counters. Counters cancel each other's effect at the common bolting surface.
Good luck.