Yamaha V4 115 2-stroke carburetor adjustment ???

[mbackc]

Hello !

I am new in this forum, but I hope that someone can help me. I have a 1998 Yamaha V4 115HP 2-stroke outboard engine. I have just disassembled the two double carbeuretors, to clean it and to mount a new repair kit. The big question is: How to adjust the carbs after re assembling ??? I noted down the old settings of the pilot screws, just in case but I want to adjust it properly.

When adjusting the pilot screws, do I need a vacuum gage ? Or is the vacuum gage for adjustment of the throttle positions ? I can see that there are two plug screws at each carburetor, that is probably for mounting the vacuum gage. Can anyone advise me how to adjust this engine ? ?

Or does any one have a manual that covers this adjustment on V4 115 HP 1998 ?

Thanks for your help in advance.. .

All the best

Michael

 

[rodbolt]

Re: Yamaha V4 115 2-stroke carburetor adjustment ???

carb pilot screws at 5\8ths and the floats at about .630 with the bowl gasket installed and the carb upside down.

 

[mbackc]

Re: Yamaha V4 115 2-stroke carburetor adjustment ???

Thanks a lot for the nformation.

I gues this is the basic adjustment after rebuild. How to fine tune with the engine running ? And how to calibrate the two double carbs ? Do I need a vacum gage for this ?

Thanks in advance

 

[mbackc]

Re: Yamaha V4 115 2-stroke carburetor adjustment ???

Does anyone have an electronic repair manual for Yamaha V4 115 from 1998?? Guess i could get an answar to all my questions in this one...

 

[cousinabe]

Re: Yamaha V4 115 2-stroke carburetor adjustment ???

http://www.yamahapubs.com/index.do?pg=search&category=4

 

[rodbolt]

Re: Yamaha V4 115 2-stroke carburetor adjustment ???

if your rebuild job is correct,the linkage is adjusted correctly and the motor is in good mechanical shape the 5\8ths adjustment works.
no vacum guage to set it with.
the pilot screws DO NOT alter the idle air fuel ratio.
the ratio is set by the pilot air and pilot fuel jets.
the screw just allows more or less of this mix into the intake.

 

[1kkfan]

Re: Yamaha V4 115 2-stroke carburetor adjustment ???

I have the same engine same problem. what do you mean by 5/8ths exactly.

 

[Doh]

Re: Yamaha V4 115 2-stroke carburetor adjustment ???

5/8th of a turn out from fully turned in

 

[1kkfan]

Re: Yamaha V4 115 2-stroke carburetor adjustment ???

oh ok thanks a bunch

 

[1kkfan]

Re: Yamaha V4 115 2-stroke carburetor adjustment ???

back on the subject about the pilot air and fuel jets,i was on the yamaha site and i couldnt find an exact location of these jets. i know im asking alot but help me. I need the location of the air and fuel jets or the correct name of the parts. thanks

 

[99yam40]

Re: Yamaha V4 115 2-stroke carburetor adjustment ???

That is the correct names in the Yamaha service manual and parts breakdown. They are in the carbs.
Do you have manual for your motor? If not get one it will give you all the info needed for maintenance and repair.
If you do not understand what you are reading and have questions about it then start your own thread instead of adding to someone else's thread

 

[1kkfan]

Re: Yamaha V4 115 2-stroke carburetor adjustment ???

excuse me. didnt know this was your forum. I thought this website was for asking questions or receiving answers on marine problems.

 

[99yam40]

Re: Yamaha V4 115 2-stroke carburetor adjustment ???

If you have not read the first thread yet please do.
It makes things run a lot smoother if you follow it.

http://forums.iboats.com/showthread.php?t=250876