300hp Yamaha experiences??

232 GULF

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I have a 250 Yamaha ox66 that's crappin the bed and have decided to repower my 232 Gulfstream. The grady white/yamaha dealer near me said they would put a 300 yamaha on it....seems like the cheapest and easiest time-wise. Any personal experiences with a 300hp yammy? Any thoughts?
 

NIGHTIDES

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I know of two Grady 232's that recently went through a repower. One from the 250hp Yam and one from a 225hp Johnson. Both went with the 300HP ETEC.

Both have only raves about the new power. WOT at about 40-41MPH.

Good luck w/ your choice.
 

jekyl

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I have no experience with the 300 four stroke but a friend who put a 300 hpdi has had nothing but trouble, and it's only done 250 hours after 3 years.
 

Doctorsrh

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I have 80 hours on a 300 hpdi on my 24 Explorer. I haven't had any issues. Runs strong, pretty quiet, had all the updates completed. I don't beat my engines, and I have read/heard of problems with the 250/300 hpdi's, but so far, I'm happy with the engine.

I did purchase Towboat US, just in case.
 

Parthery

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The 300 4 stroke Yami is a detuned 350....and they both weigh A LOT. (Like 800+ lbs.)

If you have your heart set on a 300, I'd look at either the E-Tec or the Zuk...or wait til the Miami Boat Show. Maybe Yami will finally get their 300 out that is based on the 250 block.... :roll:
 

SoutheastFL

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NIGHTIDES said:
I know of two Grady 232's that recently went through a repower. One from the 250hp Yam and one from a 225hp Johnson. Both went with the 300HP ETEC.

Both have only raves about the new power. WOT at about 40-41MPH.

Good luck w/ your choice.

Getting only 40-41 mph at WOT on a 23' boat with 300 hp is TERRIBLE ! Check out the 300 hp Suzuki, it doesn't weight that much more and is alot better engine.
 

Legend

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I had a 2004 Gufstream and remember toying with the idea of adding the 350 when it first cam out. The dealer told me the stern could not handle the torque that was delivered by that monster engine. The was a transom redesign to accomodate the big engines on later models of GW line.
 

BobP

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On a Grady Drive single Gulfstream, the flange cannot accept the wider and taller transom bracket of the F350, you would need a new Drive suitable for the F350.

Other than that the Gulfream would be fine with the F350, or should I say fantastic ! 50 mph boat I bet.
 

billydoos fishing always

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engine repower

Hello

I have a freind who owns a charter bussiness.He has 4 24ft grady whites ransing from 1986 to 2000 and he has gone with the suzuki 250s and 2 300hp on his boats hes says that he loves them also he ran yamaha for 15 years but didnt like that he couldnt get parts when they broke down everything had to be 2 weeks from japan so he went with suzuki and is getting alot better service.When repowering you should consider who will give you the best service and fastest service its great to have a yamaha or suzuki or merc but if you want to be able to get it fixed fast if needed so you can enjoy it,thats why I would look at who will give you the best service and is close to you and where you use your boat.

tight lines
 

NIGHTIDES

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BobP said:
Other than that the Gulfream would be fine with the F350, or should I say fantastic ! 50 mph boat I bet.

Grady did a test of the 350 on the 232 and came up with 50.4MPH as a top end. (Nice guess BobP..!!) But the real world results will almost certainly be less. Hard top, ducers, bottom paint (especially), etc will all impact the final #'s down.
 

BobP

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I figured if I could get 45 mph with 400 ponnies and one more motor leg of drag and more hull weight than Gulf, then a 350 single ought to out do me.
 

JGH

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I have a 300 Yamaha 2-stroke hpdi on a GW 257 CC. Almost 500 hours and (knock wood) no problems. If I were buying now, I'd go with the 350 4-stroke for added power, less smoke and more quiet.
 

232 GULF

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Thanks for the posts guys.....SoutheastFL - the Gulfstream isnt any 23' boat if you aren't aware. It has a 9'3" beam and weighs about 4500lbs w/o an engine so 40-41 mph WOT w/ a 300hp is EXACTLY what you should expect. The 350hp yamaha on a gulfstream tops out at about 50mph. Anyways, my dealer (authorized grady/yamaha dealer) told me that grady white won't allow them to put any more than a single 250 on, even with a new bracket. So i guess my only option is twins, the 250 isnt enough power. I've heard 150s are the way to go......
 

BobP

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Go to a boat rebuidling/repair/custom shop, they can order the right bracket for the job and install it. The aftermarket brackets are custom made to order, not the Grady Drives.

Since the bracket spreads out the forces, and I expect the bracket ordered for a single F350 to have a wider flange at the transom than usual, the boat doesn't know the diference between twins or a big single or equal total torque/ HP. In other words, the bracket needs to splay out more as it moves towards teh transom from teh motor.

Show this thread to the boat shop.

Make sure a Grady Drive is not ordered.

Just a note, the F350's gear case leg may be partially in the water unless you discuss this with boat rebuilder, then he has to include the necessary bracket fab dimensions to allow the motor to tilt up all the way and not have the cowl hit the transom before T&T is out of range. He also has to make the rear bracket face more vertical of an angle on the bracket than teh Grady Drive is, 5 deg more should do it.

If you are wondering why Grady won't do this, is because Grady wants you to upgrade to a NEW Gulfstream to get the F350 !