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Doug E.
Doug E., Kawasaki Master Technician
Category: Motorcycle
Satisfied Customers: 2886
Experience:  Professional motorcycle mechanic since 1978. Vintage motorcycle restorer.
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I have a 1985 yamaha phazer 485cc snowmobile..carbs

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I have a 1985 yamaha phazer 485cc snowmobile. It started but would not reve when giving it gas. I took off and cleaned the carbs. I started it with the same results. I removed a small resonance chamber between the carbs and reed valve. This opens a 1/2 inch open air way. With the engine idleing, it instantly reves up and sounds like have to bock up these air holes to stop it or it seams like it is runing wide open. I checked the air intake chamber and there is no blockage. could the carbs be flooding? any other ideas would be helpful..thanks john

It's possible the carbs are flooding. Do you see any gas leaking from them or do you smell gas when running the motor? What color are the plugs burning? If the motor is flooding, the plugs should be wet. Also, if the motor is flooding, when you open the throttle the engine should smoke heavily and sound like it's loading up. If it's more of a hollow sound, the it's something else.

When you pull the boost canister line, you are suppling more air to the motor and leaning it out. That should be an indication that you are running too rich. Have you verified the chokes are opening and closing all of the way?

Pull the impulse line from the fuel pump to the engine block. Is there gas in this line? If yes, your pump is going bad and needs to be replaced. Gas is running from the pump directly into the motor.

Check those things and let me know what you find.

Customer: replied 7 years ago.
I checked it out last night. the pluggs are wet. The only thing that would make sense is the floats are sticking ang letting the Carb flood. It idles fine but if you give it gas it smokes and boggs down. The fact that pullng the boost canister lets it want to run wide open with the throttle at idle could indicate it is getting all the gas it wants from somewhere. It make sense. I will pull the carbs and see wnat is up....
You may need to replace the float valves, but the problem may be in the needle or main jet area.

If it idles fine, then the floats aren't flooding out the motor. It sound more like the main jets are not installed, or the main jet holder washer is missing, or not seated. Also check the needle in the slide. It may be stuck so it's all the way up and not dropping with the slide. They could be on the wrong side of the retainer or something on that order.

Customer: replied 7 years ago.

This seld was bought new in 1985. I have had it since. Everything was stock and it ran fantastic till 2 years ago. I just let it sit and decided to clean the carbs and see what was wrong. Nothing carb or engine wise was ever done. 2 years ago there was some water in the gas some how from the gas station intown. I cause problems for the local shop's rentals too. I just never took it apart till now.......Just some background...The carb bowls were full of crud. the blew out all the hole but DID NOT take apart the valve under the floats.I will take a closer look.

I will re check the carbs. I do not see a needle / slide type on this carb. I have that on some other sleds. There is a small type needle type on the top exhaust side. I will check that too...

I thought they had moved away from those carbs. Sorry for not checking that.

I am posting a diagram below of the carbs. You need to strip them completely and soak them in a carb cleaner. I would use Yamaha carb cleaner. It mixes with water and cleans up with water. It has some toxic fumes, but nothing compared to the stuff they sell in auto stores that will leach through your skin and kill you. From the condition of the carbs that you describe, there is no other way to restore them. It will save you time and money in the long run.

You should drain and dry the tank and inspect the fuel pump. Anything that was in your carbs was in your fuel pump! You can get a pinhole in the diaphragm and it will leak gas into the crankcase while riding.

I forgot to post the diagram...... The cold must be going to my brain.

Customer: replied 7 years ago.
Yes that is it......I am giong to the UP tonight. I will take this appart and look at it next said it could be gettng gas through a line that goes straight to the engine?
Yes, the fuel pump is driven by the impulse from the engine crankcase. If the diaphragm has a leak, gas will go directly into the crankcase. If you pull the line from the crankcase and see any gas in it, then the pump is bad. It's located under the airbox and can rebuilt, but they are cheap enough to replace.

Customer: replied 7 years ago.
I will look..thanks
Customer: replied 7 years ago.
Hi Doug. I am back I will check out the engine and carbs today when I get home. I blew the head gasket on a 1987 Yamaha v-max this weekend. I had to bring it home too.....
The fun of snowmobiling!
Customer: replied 7 years ago.
Hi. I took the carbs off agian...I will clean them way better today...The pulse vaccum line for the gas pump did not have any gas in it.....
ok, let me know how it goes.

Customer: replied 7 years ago.
I put it back on. Still running the same. With the throttle closed in Idle. the only gas that is going to the carb is from the warm up idle. There is an adjustment on this #20 21 0n #12. I will see if it is closing or not. there is no other fuel able to get into the engine.
I am posting the carb manual. Take a look at all of the photos and diagrams. Are you sure nothing is missing? Check all of the jets, washers and rubber plugs.

Be sure to look through all of the passages with a bright light and magnifying glass. You may have missed a piece of crud in one of the air passages that isn't normally an issue.


Edited by Kawasaki Doug on 2/5/2010 at 10:22 PM EST
That covers a couple of different models so ignore what doesn't match your year and model.

Customer: replied 7 years ago.
Hi Doug, Thanks for hanging in there with me. I Did not get your email till Monday.I tried everything. i did not clean the carb as good as the instructions but I did blow air and Carb cleaner through every jet, hole I could fine. I adjusted the cold start to close and it still idles, but when you give it gas, it does not go. I made an air space between the Carb and air box just to make sure there was no restriction in the air box. Like not getting enough air when you give it gas. No change. Still runs when when the boost canister is pulled out. There is gas getting to the carb from somewhere . If I close the pilot screw, the only way gas could get to the boost caniter area with the throttle not pushed is through the cold start plunger. IF this is closed or in with the cold start lever not in use, there should be NO gas in that front area. But there is. If the floats are not floating to close the gas input and the gas is being sucked up through the cold start plunger this gives it all the gas it wants. I am going to plug up the cold start feed through the starter plug area if possible. Then there should be no gas in there. I have a set of carbs with a top slid pull that I took off my old same yr & cc phazer before I junked it. I cleaned those carb last night, IF notheing i will put thiose in. I did not want to use those because they made my last phazer fast but loaded it up too much on the trails.going slow.. I checked the impulse line from the fuel pump. there was no gas in it. do you know if the engine would rund that fast and get that front booster chanber area wet with gas if that fuel pump was bad. It was bone dry but if I plug up all the gas and it still runs, maybe it shoots gas only when it is running.
I'm going to go over some carbs later and see what other ideas I can come up with.

Are you sure this is a fuel problem and the motor isn't cutting off from the safety switch? You might want to attach a spark tester to one of the plug wires just to make sure the ignition isn't shutting off as you open the throttle.

Customer: replied 7 years ago.

No . I will see when I get home. I will un plug the safety. Isn't that the 2 wires on the carb ??

Can the cold idle be wore out so gasoline is going around it??


I have to rebuild the Vmax 540 Engine when I get home.The gasket kit came in. It is snowing and we could ride it around if I fix it......I will play with the Phazer after that. I have these high performance carbs I may just put on to see what happens if un plugging the shut off dosen't work...Maybe that is it. But is dosen't just die. It boughs down and burn rich with smoke with no power. then if yolet go it goes back to normal idle....

I was sure you were going to find that one of the passage plugs was missing and gas was coming up a passage it shouldn't. I'll have to go over everything tonight again and see if I am missing anything.

Customer: replied 7 years ago.
I made sure those little plugs were in the proper spots.
The impulse canister holds a charge from the engine and delivers it when the throttle is opened again. It has no moving parts so should be no problem unless the reeds are bad. I would take a peek at those to make sure they are closed and have no cracks.

At idle the only fuel going to the motor is through the idle circuit. When you pull on the choke, gas flows from the float bowl into a large passage and into the motor. The plungers must be all the way down and sealed to stop the flow.

There is no way for extra gas to enter the motor unless something is missing or there is a crack between the passages.

Are you sure it's running too rich when you open the throttle? Does it load up and smoke? Try putting on the choke a little and opening the throttle to see if it makes it better or worse. Also, be sure to check the safety switch.


Customer: replied 7 years ago.

Yes I checked everything that is why it was driving me crazy and Thanks to you I got help...You FIXED IT!!!!!

It was right there and I did not think of it till you mentioned it. I unplugged the Throttle safety from the carb and to itself. Engine runs GREAT.....It is the shut off switch...

I been rebuilding engines and carbs for 30 years. 2 cylce just for myself. I though I was loosing it. I must be getting OLD. Thanks for all the suggestions and for finaly giving the correct answer!...

Normally that will cause a miss or it to shut off, not a flooding condition, so it wasn't at the top of the list. Glad to hear you can get out riding.

Customer: replied 7 years ago.
How or do you get paid for this?? is there anything I need to do??
Just click the "ACCEPT" button. Thanks.

Doug E. and other Motorcycle Specialists are ready to help you
Customer: replied 7 years ago.
Gave you a "Tip". Thanks for the help....hope you get it...johnm
Thanks! I appreciate it.