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Thread: How do these old 50hp yamaha 4 bangers go

  1. #1

    How do these old 50hp yamaha 4 bangers go

    Any idea howthese old girls go? I picked it up for next to nothing, engine is in immaculate condition not even a tiny hair line scratch on it

    However the cylinder head is corroded from not being flushed i have had a honda in similar cortoded condition that cost $120 to weld and machine so its repairable

    Just wondering how they go its a old carby 4cyl 50hp 4 stroke i may chuck it on a old quintrex fishabout

    It wouldbe under powered on a haines 146 i'd imagine

    Its the tiller, elec start, elec tilt trim model
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  2. #2

    Re: How do these old 50hp yamaha 4 bangers go

    Bugger pics turning sideways
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  3. #3

    Re: How do these old 50hp yamaha 4 bangers go

    Being tiller steer, it wouldn't be practical on a Haines, the old carby models were OK, but, nowhere near as good as the later EFI motors. That's pretty bad corrosion, did you buy it knowing it had "issues"?

  4. #4

    Re: How do these old 50hp yamaha 4 bangers go

    Quote Originally Posted by Noelm View Post
    Being tiller steer, it wouldn't be practical on a Haines, the old carby models were OK, but, nowhere near as good as the later EFI motors. That's pretty bad corrosion, did you buy it knowing it had "issues"?
    Yeah i know it had cylinder head corrosion and the head was already dissasembled, i check the blocks matting surface and it appeared really clean a little build up in the galleries

    The head has a medium amount of corrosion but should be easily repairable, the while engine exterior and under the cowling is immaculate just aprevious owner had no idea on flushing

    The 4.2m dory was offered to me but i didnt have anymore cash and the trailer the dory was on was absolute cactus

  5. #5

    Re: How do these old 50hp yamaha 4 bangers go

    Might be able to find a second hand head somewhere, what do you intend doing with it? another project?

  6. #6

    Re: How do these old 50hp yamaha 4 bangers go

    I hadno intentions on picking up another project just yet but this came available and i grabbed it

    It just needs the head repaired or replaced, bokted on andit should be a goer

    I have no project for it to go on or anything atm but i seen it and thought it was a really good thing to snap up

    The seller said he was quoted 2.5k for a replacement used head but i found one on usa ebay for $500 shipped or i can repair this obe for under acouple hundred

    Just not actually sure what to do with it, place it on a small light weight boat would be great its apretty much desirable engine on the used market guys were calling the seller wanting to drive down from brisbane to purchase it

  7. #7

    Re: How do these old 50hp yamaha 4 bangers go

    I pulled the cam cover off a tiny bit of pepper rust i gave everything a coat of door lubricant it was next to me so i used that

    Gave the cam a few turns and it spins freely

    Valves will need to be removed and soda blasted

    Not sure if i will clean the face or leave that up to the shop

    I may just wheel this engine into the shed once its fixed and running and keep it for a future project its to good to let go

    I'll focus on the big boat and maybe keep an eye out for a suitable tinny either tiller steer or i can convert this yammie to forward controls

  8. #8

    Re: How do these old 50hp yamaha 4 bangers go

    Few more pics
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  9. #9
    Ausfish Silver Member
    Join Date
    Mar 2015
    Location
    Kalbarri, WA

    Re: How do these old 50hp yamaha 4 bangers go

    Valve seats shot? looks to be corrosion around the outside of all the valves, does it extend underneath? Wouldn't bother with soda blasting the valves, clean them up yourself, it's the seats/stems/valve guides and seals I'd be more worried about.

  10. #10

    Re: How do these old 50hp yamaha 4 bangers go

    Hey Ran not sure yet about the valve seats i will have to dissasemble the head than soda blast and inspect all the componants, i have a soda blaster as part of my tools along with valve removing tools

    I'll post picsup when i get around to it

  11. #11

    Re: How do these old 50hp yamaha 4 bangers go

    looks like bottom two cylinders have been under water looking by the rust on the valves or a gasket let go , hopefully its only a clean up job and nothing serious like a cracked head , got to hand to you you do find some bargains , that should be a comfortable rebuild for you

  12. #12

    Re: How do these old 50hp yamaha 4 bangers go

    Hey Cat the blokelived 200 meters from the river u can see the river in the back ground of the engine pics just behind his swimming pool i think thats what caused the rusty valves just the head sitting in his garage with salt water in the air

  13. #13

    Re: How do these old 50hp yamaha 4 bangers go

    How would a little haines v133 like this handle the power of 50hp? Im not going to buy this boat just asking as im curious

    https://www.gumtree.com.au/s-ad/wyom...mpaign=socialb

  14. #14

    Re: How do these old 50hp yamaha 4 bangers go

    I got 1 quote $300 just to weld, bloke said it'll need new valve stem seals and valve seats cut than machined face... for that kind of dollar i can get a used head out of the usa

    I will go see old mate that done my honda head

    I may even give it a whirl my self, strip it bare, soda blast the face and all corrosion than place the head in a bbq and heat it to 70celcius than remove and mig weld while its warm

  15. #15

    Re: How do these old 50hp yamaha 4 bangers go

    MIG welding that will result in needing another head whether you want to or not. It will need to be perfectly welded, then machined flat.

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