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Yanmar

Jan 20, 2017
78
Yamaha 33 Vancouver
I’ve a Yamaha 33’, and was curious about the difficulty of replacing the stock 2GM with a 3GMD. Can the engine bay incorporate the larger engine?
 
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Likes: StargazerP303
Jan 30, 2012
1,089
Nor'Sea 27 "Kiwanda" Portland/ Anacortes
I’ve a Yamaha 33’, and was curious about the difficulty of replacing the stock 2GM with a 3GMD. Can the engine bay incorporate the larger engine?
Yes. Except the motor mounts will not match up because the motor is longer/wider. That means shorter shaft or longer stringers and that means you might need additional clearance on the forward/back end maybe both. Do you have the space? Perhaps the width is different so the stringers will be too narrow. Also likely the height will not match either. These all need to match up otherwise one cannot align the shaft to the motor to say nothing of a solid motor mounting structure. Remember the shaft pushes on the motor, thence on the motor mounts, which pushes or pulls the boat so these things need to be paid attention to.

Just a preview. There are other gremlins in every re-power. They are usually not the nice kind.

Charles
 
Jan 20, 2017
78
Yamaha 33 Vancouver
Thanks, Charles. Excellent points. I’m okay on width and height, as the only change is the additional length of a cylinder going from the 2GM to 3GM. The engine bay is relatively roomy with the 2GM, so this might work with a bit of fiddling here and there, and certainly a smoother more reliable ride on three cylinders.
 

Satori

.
Sep 25, 2008
13
Yamaha Y-30 MkII Sidney BC
Kampu, why the change? Problems with the 2GM or just looking for more power?
I'd love to replace the YSM12 in my 30, but just to get a little more oomph. (currently the mortgage prohibits me from actually pursuing that)
 
Oct 22, 2014
352
Pearson P303 #221 RockPort Maine
One thing I would look at is "Parts available 3GMF". Yes, more and more parts are going, going.. gone! Yes, you can find them but at a very steep price if you noticed for the 2GM series. So if, you have your mind set on doing it make sure you use THE new brand footing and not the old style or original series. 100,150,75 etc. Just take your time and talk around on parts too. Capt Rob 2GMF-13.
 
Jan 20, 2017
78
Yamaha 33 Vancouver
The 2GM rating is 13hp when factory fresh, and that fresh glow is decidedly off the unit now. No issues mechanically, but we were compromised by its lack of gusto on one occasion: we needed to get out of some bad weather, and couldn’t gain any purchase against the wind and tide. Fortunately, we found an alternative ad hoc wind/wave break to hide behind, but things could easily have taken a nasty turn had we not found the alternate.
 
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Likes: Satori
Jan 20, 2017
78
Yamaha 33 Vancouver
One thing I would look at is "Parts available 3GMF". Yes, more and more parts are going, going.. gone! Yes, you can find them but at a very steep price if you noticed for the 2GM series. So if, you have your mind set on doing it make sure you use THE new brand footing and not the old style or original series. 100,150,75 etc. Just take your time and talk around on parts too. Capt Rob 2GMF-13.
Cheers mate.

I shop on eBay and Craigslist for most of my 2GM parts, so that takes some of the sting out of ownership. Hopefully, it’ll be the same with the 3.

Thank you for the footing info.
 
Oct 22, 2014
352
Pearson P303 #221 RockPort Maine
Cheers mate.

I shop on eBay and Craigslist for most of my 2GM parts, so that takes some of the stings out of ownership. Hopefully, it’ll be the same with the 3.

Thank you for the footing info.
Good, then you have some ideas about what you are going to face down the line $$$. One suggestion here is above all purchase a complete set of gaskets and rings for that engine to keep. when you use one just replace it this way you'll be able to shop around at your leisure and you will SAVE $$$$
Capt. Rob
 
Jan 20, 2017
78
Yamaha 33 Vancouver
It looks like that 3GM kicked up a bit of a fuss getting in there, but it slotted in perfectly in the end. The adaptation seems quite simple, as it only involves a linear translation. Quite doable, I can see. Thanks, Mike!