yamaha 40 hp 2 stroke

b00tsyo42

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Hello, i am new to boating and have yamaha 40 hp two stroke 3 cylinder oil injected possibly 2002 ? numbers on it are 6H4 4 OVETO L544784 U . motor starts and runs ok a bit rough and conks out often. i have several questions, how can i more accurately identify year and model, can i get service manual for this engine ? i wish too service this engine and gearbox myself and if easy enough decarbonise engine and clean carbies any tips on how too service and get this motor running sweet as i can would be appreciated. thanks b00tsyo42 in western australia:)
 

Silvertip

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Sep 22, 2003
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Re: yamaha 40 hp 2 stroke

There are a number of aftermarket outboard motor manuals for each brand but the best service manual is the OEM manual since it is produced by Yamaha and Yamaha built the engine so they know it best. Visit your Yamaha dealer. Don't know if you can order them on-line but I would think so. As for carb cleaning it is a fairly basic operation. DO NOT disassemble all three carbs at the same time. Doing one at a time will provide you the opportunity to look at one of the other carbs should you forget how it went back together. Kits are available on-line. Decarb is smoky process in which a strong mixture of RingFree, SeaFoam or other additives are used to dissolve carbon deposits. One thing you need to do after rebuilding carbs is to perform the linkage synchronization process. Carbs and ignition advance linkage must be spot on to for proper engine operation.
 

robert graham

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Re: yamaha 40 hp 2 stroke

Super simple and dependable motor!...after you get it running like Grandma's Singer Sewing Machine consider installation of a fuel/water separator(Walmart/Attwood $27), learn to drain each carb on a fairly regular basis and especially at lengthy lay-up times(several weeks or months), and consider using a fuel stabilizer additive like Stabil or Seafoam in your gas tank all the time to prevent fuel break down or deposits. Clean, fresh fuel all the time and it'll eliminate about 3/4 of all potential running problems. Good Luck!
 

b00tsyo42

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Re: yamaha 40 hp 2 stroke

Thanks for the helpful replies. I went too my local yamaha outboard dealer today and was told they do not supply manuals for my model engine. Does anybody know wre i can try to source a manual for a 99 model u series 40 hp oil injected 3 cylinder with power tilt from ? Any ideas will be followed up. Thanks, bootsy mandurah western australia.
 

99yam40

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Re: yamaha 40 hp 2 stroke

So, you have identified your motor as a 2002 and now as a 1999, which is it?

Have you tried looking at a Yamaha site?
Here is one for the USA and Canada, but I do not know if there is one for down under.

YAMAHA MANUAL STORE


I would think your Yamaha dealer would have been able to order one from Yamaha for you
 

squealer

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Re: yamaha 40 hp 2 stroke

you can find factory service manuals online for $10. imracingmanuals.com
 

Don S

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Re: yamaha 40 hp 2 stroke

Here is your model and serial number organized as they should be.

6H4 L 544784 U is the serial number.

40VETO is the model number of your motor.

Big problem is, the numbering system isn't the same as US numbers. I have tried a few times to find a site with international numbers and so far have never been lucky enough to find one.

I may have to spend some time looking again. Can't believe Yamaha is that tight lipped about their information that you can't even find out what year your motor is.

PID.jpg


Found this code number guide, from the looks of it, that 6H4 in your serial number indicates it's a 1984 motor.

View attachment Yamaha engine code numbers.pdf

Here is a previous thread by Dunruna from 2009 that helps explain it.

http://forums.iboats.com/yamaha-suzuki-outboards/yamaha-international-model-codes-310906.html
 
Last edited:

99yam40

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Re: yamaha 40 hp 2 stroke

the chart indicates the 6H4 started in 1983 and has no end date, so is continued still today(I guess). So do not see ant indication of it being made in 84.

Serial #s should indicate when it was produced, but I have never seen a chart listing years according to #s like Suzuki's

Does this thing have a letter in the lower right hand corner?
 

Don S

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Re: yamaha 40 hp 2 stroke

Yes, just found some 2000 info that shows the 6H4 on the newer ones as well. But not the 40V. and he has a 40VETO.

It's hard to say, that chart may only be good for US engines.
Seems to me if it was newer, they would be able to get a manual for it. But I'm not down under either.
 

99yam40

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Re: yamaha 40 hp 2 stroke

LIT-18616-01-81 is the manual listed for my 1999 C40TLRX on the Yamaha site
and in the electronic version of the manual I have with that LIT# says it was printed in Dec 1997, and it lists a 40VET and 40VETO as models it covers also.
I do not like the procedure for link and sync in it, it does not make sense to me and others that have seen it (probably a miss print)

PM me if you want a look at it
 

Don S

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Re: yamaha 40 hp 2 stroke

Good job of searching, looks like the same manual I have and didn't even notice I had it. Is this the one you were referring to?

Click Here
 

99yam40

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Re: yamaha 40 hp 2 stroke

Yep that looks like the one I have

Still have no idea what year his is though, but I would think the manual would work for him
 

b00tsyo42

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Messages
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Re: yamaha 40 hp 2 stroke

So, you have identified your motor as a 2002 and now as a 1999, which is it?

Have you tried looking at a Yamaha site?
Here is one for the USA and Canada, but I do not know if there is one for down under.

YAMAHA MANUAL STORE


I would think your Yamaha dealer would have been able to order one from Yamaha for you

finding out what year the engine is one of the things i am trying to do hoping it will make it easier too find a manual. the guy who sold it to me said it was 2002. the guy at yamaha dealership in mandurah said that the letter u indicated it was a 99 model and no manual was availeable for that model, all i can do is keep trying. bootsyo42, wa
 

b00tsyo42

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Feb 25, 2013
Messages
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Re: yamaha 40 hp 2 stroke

the chart indicates the 6H4 started in 1983 and has no end date, so is continued still today(I guess). So do not see ant indication of it being made in 84.

Serial #s should indicate when it was produced, but I have never seen a chart listing years according to #s like Suzuki's

Does this thing have a letter in the lower right hand corner?

yes it has the letter u in the lower right hand corner which according to my local yamaha dealer here in mandurah indicates it is a 99 model.
i see in one of the replies is a manual which may apply too my engine i check it out. thanks bootsy.
 

b00tsyo42

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Joined
Feb 25, 2013
Messages
11
Re: yamaha 40 hp 2 stroke

the chart indicates the 6H4 started in 1983 and has no end date, so is continued still today(I guess). So do not see ant indication of it being made in 84.

Serial #s should indicate when it was produced, but I have never seen a chart listing years according to #s like Suzuki's

Does this thing have a letter in the lower right hand corner?

So, you have identified your motor as a 2002 and now as a 1999, which is it?

Have you tried looking at a Yamaha site?
Here is one for the USA and Canada, but I do not know if there is one for down under.

YAMAHA MANUAL STORE


I would think your Yamaha dealer would have been able to order one from Yamaha for you

thanks i will try it. bootsy
 

b00tsyo42

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Joined
Feb 25, 2013
Messages
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Re: yamaha 40 hp 2 stroke

Good job of searching, looks like the same manual I have and didn't even notice I had it. Is this the one you were referring to?

Click Here

i think i should be able to use this one fo my engine. thanks very much you guys have been much more helpfull than my local dealer. regards bootsy.
 

99yam40

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Re: yamaha 40 hp 2 stroke

The U is not the last letter in his model # so that is incorrect about the 1996

Just some info on that manual , in case you do not notice it while following some procedures.
If you look at the idle adjustment procedure, it calls for starting motor , warming it up,and adjusting the RPM before it tells you to tighten up the linkage to all three carbs. This is impossible to do and is wrong. the steps are out of order.
 
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