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Discussion Starter #1
ok, My Buddy has a 1986 Yamaha Phazor 480cc and after cleaning the carbs it occasionaly runs amazing...

on start up it runs amazing for about 10 mins (this rarly happens anymore, its running pretty bad now) then it goes back to just ok. Bogs a little and wont go full speed. it runs this for a while. it idles and runs, but it runs like crap.

We have cleaned the carbs and I am wondering if there is some other issue I am missing. I suspect the choke, but not sure how to remedy the issue.


Also today I went out to the garage and there was gas everywhere underneath it. I took it outside and saw it was coming from the exhaust (started was almost impossible to pull). assuming flooding I Pulled the plugs off and pulled the starter and gas shot out of the cylinders. Did this to clear everything out and thats where I am now. Not sure how it flooded from sitting there, but I suspect because it was jacked up a bit in the back and leaning forward... but I thought the float bowl would seal that off...

any thoughts?
 

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Discussion Starter #3
ok, kinda what I figured. I am more worried about the poor running (could also be the same issue)

So I will look at the carbs again as my buddy put one back together without me watching and could have messed up.

Any reason to think somewhere before the carbs may be an issue such as filter, fuel pump, etc...
 

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filter would cause a starve for fuel. fuel pump only works when the sled is running or your pulling the rope. also, confirm the location of the rubber plugs inside the carbs.
 

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The plugs in the bottum of carb are not in or not in the correct openings. Remove the carbs and the bowls. First, see if the little black plugs were put back in. Second if so does each carb match. If you hold the carbs upside down and the in-take facing you (larger opening) the center and the right opening should be plugged. I think Yamadad4 can confirm that being the correct holes. But I made the mistake last season of not putting them in the correct holes and there was no top end, sled only ran about 30mph. I switched to the correct holes and now does 70+mph. That should solve problem.
 

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Discussion Starter #6
filter would cause a starve for fuel. fuel pump only works when the sled is running or your pulling the rope. also, confirm the location of the rubber plugs inside the carbs.
Oh I know about the pump, I meant could it being old or gummed up cause the running issue I was talking about?
 

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Discussion Starter #7
The plugs in the bottum of carb are not in or not in the correct openings. Remove the carbs and the bowls. First, see if the little black plugs were put back in. Second if so does each carb match. If you hold the carbs upside down and the in-take facing you (larger opening) the center and the right opening should be plugged. I think Yamadad4 can confirm that being the correct holes. But I made the mistake last season of not putting them in the correct holes and there was no top end, sled only ran about 30mph. I switched to the correct holes and now does 70+mph. That should solve problem.
What holes exactly are you talking about? you talking about putting the black plugs in? and the snowmobile drove like this (poorly) before we cleaned the carbs as well, it actually helped slightly.
 

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When you take the bowls off there is a center post with three holes/jets, which two should be plugged with black plastic plugs. It is possible that they are worn and leaking, I have seen cracked plugs that didn't affectivly seal the opeings/holes. If it ran like that before, maybe the plugs are missing.
 

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Discussion Starter #9
Naw there were two in each, ill double check before I move onto other guess I guess. I keep thinking cleaning/rebuilding the fuel pump may help too...
 

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the fact that your carbs are overfilling with fuel and loading the crankcase on into the exhaust would point more directly to a carb issue than a pump issue. play with the pump if you feel the need, but by your own description the finger points to the carbs. the choke plungers are easily removed as well when you doing a thorough carb clean, and that circuit should be serviced. i have a pic of the plug orientation i can email you if you give me your email address.
 

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Did you lightly tap the pin that holds the floats in place with a nail set?
 

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I would take carbs back apart check jet for clogs again, check the 2 black caps are in correct place. Make sure pin that holds float is in place is secure in the housing. The pin should not slide back & forth. If it does lightly tap into hole pin should have a rectangle part by the head to keep in place.
 

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I do not believe the pin would come completely out of the correct position but it can move from side to side enough that it will not keep the float in the exact position. The pin will hit the side carb housing preventing it from coming all the way out but it is supposed to stay in the hole and not move at all.
 

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Discussion Starter #18
I do not believe the pin would come completely out of the correct position but it can move from side to side enough that it will not keep the float in the exact position. The pin will hit the side carb housing preventing it from coming all the way out but it is supposed to stay in the hole and not move at all.
This is true, I opened it up and played with it a bit, and it cannot come completly out, but it come out enough for the float to sag on one side.

Tapped them both in with a hammer and good to go.

Also the black plugs were in correctly, but there appears to be a small leak on the intake manifold, thinking that may be the cause of poor running. Thoughts?
 

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I would think any leaks in the air/fuel system would cause motor not to run well.
 
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