I have a 92 Phazer with the PTO side carb running to rich, I have cleaned and checked it out several times including setting the float, the PTO side is so rich it bogs out the machine so it won't move, simply by slipping the boot off the PTO carb it will run fine, its not the pulse line, fule pump, air box, ect. Picture below shows how moving the boot make it run. Any ideas.
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Vmax540
VIP Member
Strange.......... No air flow to P.T.O. carb would make that side rich ? Butterfly valve moving with throttle ? Obstruction in P.T.O. side of air box ? Stuck inlet needle/float on that side ? Are the rubber plugs in bottom of carb in correct holes ?
The plugs have me baffled, the shop manuel shows them center and left looking down from the top which leaves the pilot jet open but I have heard the plug is supposed to be in the pilot jet, both carbs are the same right now, anyone know which way for sure. Click on picture for larger view.
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How are you needle seats? I had 10,000kms+ my old phazer and the needle seats were shot. Did you do a leak test on your carbs? What kind of shape are you reeds in? Check to make sure your floats are working properly.
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Reeds are fine changed the needle and seat along with the float, runs fine up to 4,000 rpm and than bogs, got me stumped, thought the clutch might be bad so switched with another nothing seems to make any differance, new pistons and rings, don't have any idea what to do next.
OZ
yes but...
Choke?
Disconected the choke to check it out not the problem, going to try a leaner jet tomorrow but can't believe I need to go down to a 135 at 1,000', my daughter inlaws and wifes machine run perfect with 138.5's but it can be anything at this point.
I would not get into changing jets yet. You are definetly getting too much fuel. You need to figure out why? hmm
choke plungers is where I would start
you say you disconnected the choke, but did you actually remove the plunger and make sure the plunger is seated all the way down in the hole? because if it doesnt seat to the bottom, your running with the choke on, no matter where the little lever is on the dash. Its very common to find white corrosion in there and it holds the plunger up off the seat, thus allowing extra fuel to go thru the choke circuit, and youd need more air to help get the mixture back to being useable.
you say you disconnected the choke, but did you actually remove the plunger and make sure the plunger is seated all the way down in the hole? because if it doesnt seat to the bottom, your running with the choke on, no matter where the little lever is on the dash. Its very common to find white corrosion in there and it holds the plunger up off the seat, thus allowing extra fuel to go thru the choke circuit, and youd need more air to help get the mixture back to being useable.
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Yes choke plungers were definately seated, I didn't think it was the choke because the engine runs fine up tto 4,000 rpm. Probably something simple but running out of things to check, maybe check timming next, or off to the dealer. 
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Vmax540
VIP Member
Simple mistake but, I'm Fairly sure one rubber plug Must cover the pilot and the other one beside it ! ? !
Vmax540
VIP Member
Check out the "84 Phazer problem" post from 5/21/05 !
B. you said you originally brought it in for carb cleaning. Did it run OK when you brought it in and just wanted to service it? If this is true then the carbs were cleaned and assembled incorrectly.
When you take the float bowl off there are 2 rubber cap plugs covering passages. The plug should cover the center passage and the pilot jet. If the cap is on the center and the opposite passage from the pilot jet the sled will go up to about 6000 and sound like you pulled a plug wire. Or one of those plugs could be missing.
B. you said you originally brought it in for carb cleaning. Did it run OK when you brought it in and just wanted to service it? If this is true then the carbs were cleaned and assembled incorrectly.
When you take the float bowl off there are 2 rubber cap plugs covering passages. The plug should cover the center passage and the pilot jet. If the cap is on the center and the opposite passage from the pilot jet the sled will go up to about 6000 and sound like you pulled a plug wire. Or one of those plugs could be missing.
Sorry for doubting you V540, I checked my wifes machine which runs perfect and they do have the plug in the pilot jet, looks like the service manuel is wrong, at least the picture is. Machine runs fine now. Thanks for the help guys.
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Boondocker-1
New member
check plugs? check wires? check coils? TORS?
84phaser
New member
- Joined
- Mar 27, 2005
- Messages
- 18
Interested in solution!
Hi,
I am interested in the solution if you find out what is wrong? If a dealer fixes please ask what the issue was. I will look for future posts. I have similar issues with an 84 phazer. Best of luck!
Thanks
84 phaser
Hi,
I am interested in the solution if you find out what is wrong? If a dealer fixes please ask what the issue was. I will look for future posts. I have similar issues with an 84 phazer. Best of luck!
Thanks
84 phaser
Sounds like you found the problem with the location of the rubber plugs in the carbs.
Over the life of the 485, Yamaha has placed the rubber plugs in different locations in the Mikuni B carbs. The engine is then tuned accordingly. Some sleds had only 1 plug per carb, and others 2 plugs. Make sure the plugs are in the proper location for the rest of the setup. The Tech Update manuals of past years have some good info on this.
Over the life of the 485, Yamaha has placed the rubber plugs in different locations in the Mikuni B carbs. The engine is then tuned accordingly. Some sleds had only 1 plug per carb, and others 2 plugs. Make sure the plugs are in the proper location for the rest of the setup. The Tech Update manuals of past years have some good info on this.
It was the rubber plugs Ding, very exasperating since I had the manuel and the info was wrong. On this machine the center and the hole toward the MAG (pilot jet) were the right combo. Ding the problems you describe are exactally the same as I was having, fold the boot over like I did in the first post and see if it improves the performance. Thanks for all the help guys. 
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