Yamaha 4.3L repower

ngoldenm

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Hi guys. It's been a while since I've been on here. I have a 4.3L Yamaha that has bit the dust. I searched on here and turned up some good info, but I still have some questions for anyone who has some answers. I'm a complete newb when it comes to this stuff, so don't be afraid to elaborate on your answers.

I read on here that the right vintage 4.3L Vortec would work to replace it. However, my boat mechanic said that it would be pretty expensive to do that because none of the accessories would bolt up to the engine and would need all new brackets to make it work.

What year model engine should I be looking for? Boat model is 1991.

What is interchangeable between the engines accessory wise? Would I have to get different brackets for everything or would all of it bolt up?

Basically, I just want to get something in it to get it running as cheaply as possible and then sell it. I'm tired of this headache. I'll then look for something with a Merc or Volvo in it. Thanks in advance.
 

ngoldenm

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Re: Yamaha 4.3L repower

I just sent him an email. Thanks for the link.

I would still appreciate any advice that anyone has. Thanks.
 

Bondo

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Re: Yamaha 4.3L repower

I read on here that the right vintage 4.3L Vortec would work to replace it. However, my boat mechanic said that it would be pretty expensive to do that because none of the accessories would bolt up to the engine and would need all new brackets to make it work.

Ayuh,... yer mechanic is Full of it...
Vintage to vintage, a Chevy 4.3l is a direct swap, Long block for long block...
It's the Yamaha dressin's that the Problem...
 

Bondo

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Re: Yamaha 4.3L repower

Ayuh,... Virtually All the Yamaha parts are NLA, unless Capt. Ken has 'em...
 

ngoldenm

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Re: Yamaha 4.3L repower

Ayuh,... Virtually All the Yamaha parts are NLA, unless Capt. Ken has 'em...

But assuming that the only problem is in the short block of the Yamaha engine, I should be able to just direct swap over all the existing components to a correct vintage 4.3L Vortec long block and get it running?
 

Bondo

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Re: Yamaha 4.3L repower

But assuming that the only problem is in the short block of the Yamaha engine, I should be able to just direct swap over all the existing components to a correct vintage 4.3L Vortec long block and get it running?

Yes, but that's a Big Assumption....
And it's a Chevy motor, wearing Yamaha dressin's...
 

ngoldenm

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Re: Yamaha 4.3L repower

Yes, but that's a Big Assumption....
And it's a Chevy motor, wearing Yamaha dressin's...

Well, everything else checked out. We pulled the heads because we found zero compression on one cylinder and found a hole in one of the pistons.

The only options I can see at this point in order to get it running are

  1. replace piston and fix cylinder and hope everything comes out well
  2. find replacement vortec and bolt everything up to it
  3. find a donor boat and replace everything Yamaha

If a 4.3L Vortec long block will bolt up easily using all the Yamaha accessories, I think that might be my cheapest option if I can find a decent one from a junkyard.

If there are any other options that I haven't considered (besides selling it as is, which I am still considering), please let me know.
 
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