Yamaha 6 HP, what year?+ Rust in tank

lynnyrd

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May 8, 2001
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I just picked up a Yamaha 6 HP from a Pawn shop today and I would like to know what year model it is, the model is 6SG. Overall it looks to be in great condition, the outside has a few scratches here and there and the prop has a few small dings. Under the top cover it looks Brand New. It also came with a nice Yamaha tank, When I got home I noticed a funny smell like the fuel has been sitting in the tank for a while, also It looked a little rusty in the tank. I am now worried that the pawn shop might have tried to start the thing with this old rusty fuel!! They gave me a 30 day return on this motor if it does not run, so I would like to test out ASAP, but I'M worried about this rust, should I clean the tank up good and give it a try? Or should I also try to clean the Carb out just in case they tried to pump rusty fuel thru it. Also how long does it take for the fuel in a tank to get foul like this? And what is the best Way to clean this old fuel and rust out so that it will not affect the motor. Also it says on the motor to run at 100:1 mix, does yamaha make a special mix for this motor that I should use? I paid $175.00 for the motor so if it runs I think I got a good deal. Thanks for any help you can give this novice.
 

12Footer

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Re: Yamaha 6 HP, what year?+ Rust in tank

Pull the plugs,and squirt some decarb cleaner or WD40 in there while you clen-out the tank.<br />If it had rust in the tank, I would remove the bowl on the carb and clean it out good.<br />2cycle fuel starts to go away after 3 or 4 weeks,and turns to varnish after a year or so. That smell is varnish.<br />If the tank is just rust-colored, with no heavy pitting or flaking, you can take some WD40 and a rag and coathanger, and clean most of it out.<br />100:1 is awfull light on the oil,but i wont second-guess Yamaha. 100:1 is usually recommended for break-in,but oh well.<br />That's only 8 oz TW-C3 2cycle oil to 6 gallons of fuel! I'd double check that with a Yammy dealer before crankin it up.<br /><br /><br />------------------<br />Quater Horse; The kiddy ride in front of K-Mart.
 

lynnyrd

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Re: Yamaha 6 HP, what year?+ Rust in tank

Thanks for the info 12footer, I did as you said except I did not tinker with the carb, it looks so clean and new looking I was shy about messing with it. I cleaned the tank as well as I could, and drained the old fuel from the line up to the carb. I decided to try a teaspoon full of my fuel mix in the spark plug holes and fire it off before connecting the fuel line from the tank and it fired up first pull and ran great till the fuel was gone. When I connected the fuel line and tried to pump the tank it did not seem to get pressure, at this point I got the tank above the motor to let gravity pull fuel to the carb (and it did) but it would not fire off, so I guess I need to take the float bowl off but it looks like it might be hard to get to, should I take it to the shop and let them do it or is it fairly easy to do? ( I worked on my Volks beetle for years so I should be able to do it) PS. I think this might be an 89 or 90 year model. Thanks
 

12Footer

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8,217
Re: Yamaha 6 HP, what year?+ Rust in tank

You can gently tap the carb bowl with a crewdriver handle,while squeezing the primer. it will eventually seat. But it could give you grief later,unless you are sure the needle is clean.<br />To make sure, before heading-out, set it up on the water hose, and run it. Then, while still running,disconnect the fuel line until it's just about empty at the bowl (you'll know by the sound of the motor when that is,as the RPMs will climb just a bit).<br /><br />hook up the fuel line again,pump it up.It should be ok,once some clean fuel goes thru it.
 

12Footer

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8,217
Re: Yamaha 6 HP, what year?+ Rust in tank

I forgot to answer, yes, it is easy to clean them. You should consider buying the shop manual if you plan on keeping this motor. The book will pay for itself,and keep you going. You might not have to remove the whole carb.On the bottom of the bowl,you may find a nut.Just loosen it up,and let the bowl drain.And tighten it back up. It's just that you don't want to draw the old fuel up into your engine.<br />I think you got a good deal
smile.gif
<br />Let us know how it goes.
 

lynnyrd

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May 8, 2001
Messages
16
Re: Yamaha 6 HP, what year?+ Rust in tank

12Footer, I checked out a service manual from my local library, and went ahead and took the carb off and gave it a good cleaning and adjusted the float bowl to spec. It was all very gummed up with that sticky varnish. I carefully put it back together and it fired up 2nd pull and ran very smooth....The only problem is I could not see water squirting out anywhere so I shut it down in fear of over heating... Im going to replace the impeller tommorow. Do you know if the impeller is controlled by a thermostat or should the water come out almost instantly? Thanks again for all of your help!!
 

lynnyrd

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May 8, 2001
Messages
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Re: Yamaha 6 HP, what year?+ Rust in tank

Hello 12footer, the impeller was bad, it was broken up, I replaced it with a new one and know its pumping water fine. I did notice some very light rust around the drive shaft where the impeller rides, is this a potential problem... Also I wonder if I could have hurt the motor when I ran it with the bad impeller, it ran for 30 to 45 seconds at most and did feel hot. Right now it seems to be running GREAT!! It starts right up and idles very smooth, and the gears change fine. I changed the lube in the Gear case, and it did not seem like all that much fluid came out but it did not take all that much to fill it back up so I guess a small engine does not take that much to fill up.( I did fill from the bottom and let it run out the top vent)Thanks for all of your help, I think I'm ready for Fort Nasty or I mean Fort Louden Lake here in East TN.
 
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