Should I rebuild the carbs??

[BarraHunter]

Hi all just after a bit of advice on whether or not to rebuild the carbies as in put new jets in because I've got a yamaha 40hp 2stroke and when I brought it it ran well but thee must of been stale fuel in the tank because it started to misfire at idle but go ok at revs, I pulled the carbies off and cleaned the jets out and it's run ok but I keep having the same problem again and again I've installed a fuel filter and was just thinking that maybe the jets are damaged from being pulled out so much there aw witness marks on the jets as to previous attempts of unscrewing them, also what is the correct procedure for setting the pilot screws on carbies as I was told 2.5 turns out but doesn't seem to be correct?

[boats.net]

Did you get rid of old gas when cleaned carbs? If not then clean carbs again. Jets don't wear out and if properly removed and replaced without damaging them then shouldn't need new ones.

[BarraHunter]

Yeh I used fresh fuel it now doesn't miss as badly at idle as it did but it does start to miss more as the revs increase

[99yam40]

Find a Yamaha service manual for your model motor and follow the link and sync procedure every time you reinstall the carbs

Also if there is trash in lines or pump it will end up in carbs after cleaning, as they are after the filter

[casey1240]

In addition to what has already been said, I would dump all your fuel and make sure you don't have any water in your tank. Water will sit at the bottom and will get sucked into your fuel lines and cause this problem. Also check for air leakage on your fuel line hoses and at the tank connecitions. What is the year of your motor?

[BarraHunter]

I'm not over confident on getting the year right as I have been told 3 different years the model number on the side is 40VETO I was told when I bought the boat it's a 2001, but then I've been told it's 2002 and on the yamaha boat parts centre the O apparently means 1990. Any ideas?

[99yam40]

I take it this is not a US motor as that in not a model # we would find on motors sold here. Where are you and the motor located?

Are there any more stickers with more info on the motor?

looking at this web site it looks like the 40VETO started production in 1995 and is still being made, so you will need to find more info on the motor and contact your local yamaha dealer
http://continuouswave.com/whaler/ref...odelGuide.html

[almetelo]

Hi!

Like 99yam40 sugested post the info on the stiker which may be something like this:

40VETO (code) (serial number)

Then I'll give you the exact year of production (if that is important for your needs)

I'll be glad to help

[casey1240]

Hi all just after a bit of advice on whether or not to rebuild the carbies as in put new jets in because I've got a yamaha 40hp 2stroke and when I brought it it ran well but thee must of been stale fuel in the tank because it started to misfire at idle but go ok at revs, I pulled the carbies off and cleaned the jets out and it's run ok but I keep having the same problem again and again I've installed a fuel filter and was just thinking that maybe the jets are damaged from being pulled out so much there aw witness marks on the jets as to previous attempts of unscrewing them, also what is the correct procedure for setting the pilot screws on carbies as' I was told 2.5 turns out but doesn't seem to be correct?

'

I checked my service manual which only goes to 1995 and the carb settings for a 40 hp motor are 1 1/2 turns.

[BarraHunter]

Sorry I am in port Hedland, Western Australia ,Australia
The sticker on the side of the motor goes like this 40VETO then underneath it has 6H4 L 950721
R

That is how the number are on the sticker

Thank you all for your help I really appreciate it, if I can't get it to work after this I will take it the boat shop I just want to try fix it first myself as they want $400 aus to clean and tune the carbs so if there is more wrong it will end up costing a small fortune

Thanks again

[almetelo]

Hi!

Year of manufactured is 2002 (which doesn´t mean year of sale of course)
This series have been made for US/CAN either: 40TLR

[99yam40]

I believe most motor models are manufactured the year before the year model, at least that is what I have seen.
My C40TLRX is listed as a 1999 but was manufactured in 1998.

My manual calls for 1 1/2 +-1/4 turns out on the pilot screws

[BarraHunter]

Thank you very much your help guys really appreciate it this problem has been driving me crazy!! Hopefully it's getting closer to the end will get prices tomorrow on rebuild kits as I pulled them apart and cleaned them I couldn't get the middle carny main jet out as it was badly rounded off but with a bit of persistence I hope to get it out I cleaned it out best I could there And cleaned the other two carbs the bottom arb had a bit of build up in it as the main jet was blocked I reassembled and it still misses I think a rebuild kit will be the ya to go as we'll as a fuel/water separater as well

Thank you again for your help

[99yam40]

I bought kits for mine and I think it was a waist of money, unless you need the new floats and needles and seats.

Seems the kit does not include the main or pilot jets and some o-rings for seats.
Look up and price what parts you are needing and compare to kits

Some times it takes a sonic cleaner to get it cleaned up properly or at least a couple of cleanings to get them completely cleaned up