# Yamaha carb kicking my butt



## IBBruin (Feb 10, 2009)

Here's the deal. I consider myself extremely mechanically inclined but I have this !#^&# Yamaha carb that's about to be the death of me. I'll start from the beginning so you'll get the whole picture.

Buddy of mine asks me if I can make his Big Bear run. I say I sure can. He had just got it back from the dealership and it ran good once but then wouldn't start. I check the oil and when I removed the plug, oil ran out. I mean POURED out. I drained the oil, cleaned the filter. Cleaned the plugs and filler er up with gas. 

She fired right up and I drove it around the yard 15 minutes or so then parked it in the shop. I came back the next morning and it wouldn't start. It would spin over fine but wouldn't start. Just for the heck of it I checked the oil again and it POURED out again and I noticed the fuel tank was empty! 

All the fuel from the tank had ended up in the crank case overnight. I'm thinking ok, the needle valve and seat isn't seating properly and letting the fuel run into the cylinder and it's working its way past the rings and getting into the crank case. I disassembled the carb and the only thing I found was the pin that the float swivels on was bent just a little. I called my buddy and he said that was odd because they had just charged him to overhaul the carb at the dealership just before I picked it up. 

Anyway, I order a new needle valve and seat. I had an old wolvy carb that I got a good float pin from, reassembled the carb with needle valve, seat and new (used) float pin. Changed the oil filled with fuel and fired it up.

It ran perfect for about 10 minutes then died. I immediately shut off the fuel at the tank and pushed it back inside the shop. It looked like there was about a quart to much oil in it. Fuel in the oil again.

I took the carb back apart and everything looked fine. I shook the float to see if maybe it had a crack and got filled with gas. It looked fine. Just for the heck of it I put the float from my old carb in it and put it back on the machine.

Now it gets a little technical. On the bottom of the carb is a drain. The service manual says to hook a clear hose up to the drain, open the drain and lay the clear tube next to the carb and the tube will fill up to the point of the gas in the bowl to give you the fuel level in the carb to make sure the float is adjusted properly. About 50% of the time the fuel level in the bowl will be within specs of the manual but sometime when I check it, the fuel level in the clear tube will rise all the way up to the fuel level in the tank.

I know a carb will fix the problem but I'd sure like to fix this one and not have to spend over $400 on a new one.

I'm about to pull out what little hair I have left.

Any suggestions?


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## hondarecoveryman (Feb 28, 2009)

Have you pressure tested the carb to check for bad seals ? what about cracks? I dont know either just throwin out suggestions .


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## IBBruin (Feb 10, 2009)

I don't know how to pressure test it for cracks. I've looked at everything real close. I've even looked at the bore that the seat sits in to see if I could see anything wrong. Everything looked perfect. I even put a new oring around the outside of the seat thinking it may be coming around the seat.


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## sandman7655 (Feb 18, 2009)

is the gas tank venting or is it building pressure andforcing gas into the carb?did you replace the needle and seat yet and is the float level?


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## IBBruin (Feb 10, 2009)

Honestly I haven't checked the vent tube on the tank to make sure it's venting. Dam that would be embarrassing but I hope that's it. The float is set properly according to the service manual.


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## sookiesmacker (Mar 19, 2009)

If it was the tank vent it should starve the wheeler down while running,(if it was completely clogged) I wouldn't think this would get gas in your oil while it was running.

But, like sandman said, if it sits there and builds pressure in the tank after riding, It's gotta go somewhere.


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## IBBruin (Feb 10, 2009)

Bad news/good news

Bad news is the tank vent isnt' clogged so my problem remains.

Good news is the tank vent isn't clogged so I don't feel like an idiot.


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## sookiesmacker (Mar 19, 2009)

Have you checked all of the vent lines on the carb??

Make sure someone hasn't routed the crankcase line to the carb also. I've seen some strange things take place when multiple people get their hands dirty.

I'm just slingin' stuff out there man.


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## sookiesmacker (Mar 19, 2009)

> Good news is the tank vent isn't clogged so I don't feel like an idiot.


It's not that bad. I feel like that maybe three times a day, sometimes more on weekends.





Just sayin'


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## IBBruin (Feb 10, 2009)

This carb has one vent tube about 6 inches long that pretty much runs straight up between the tank and the front of the seat.

Ya'll keep throwing stuff out there. Sooner or later someone may hit it on the head!


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## mrkd1 (Feb 27, 2009)

sounds like the dealership forgot to put all the parts in it. If it ran ok before.
Take it back or get a parts diagram take it apart and find what they messed up.
Are the cables adjusted ok?
http://www.dansmc.com/carbs2.htm


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## IBBruin (Feb 10, 2009)

This carb is almost exactly like the one I had on my 96 yamaha. I don't see anything missing but I will most definately lay the service manual beside it next time I take it apart to check. As far as the cables, there's only one and it's the throttle cable. This one has the vaccum operated slide.


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## sookiesmacker (Mar 19, 2009)

Found out anything??


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## IBBruin (Feb 10, 2009)

Nope, when I'm working on mine his takes a back seat! He lives about 7 hours from me and isn't in any hurry. I'm sure the closer hunting season gets he'll start getting anxious.


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## hondarecoveryman (Feb 28, 2009)

IBBruin said:


> The float is set properly according to the service manual.


 I have had a manual lie about the level of the float , and washed the rings out of a farmall cub tractor before i discovered the prob


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## IBBruin (Feb 10, 2009)

Well, the guy came to pick up his wheeler because a friend of a friend of a friend told him he had a briggs carb kit that would fix his problem. Him, my father and myself were sitting around the night before he was supposed to leave drinking a few cold ones and I had on old carb out and apart on the bench showing them everything I had done and just generally *****ing because it was making me look like an idiot because I couldn't find the problem. I said, let's tear that sob apart one more time and take a look. I took it back off and took it apart and couldn't find anything wrong. Just for shi..s and giggles I checked the vent line that plugs into the top of the carb to vent the bowl and I couldn't blow through it. grrrrr. I was slightly inebriated so I grabbed the vent tube and pulled it out. It ended up being about 2-1/2 feet long and run up into what we call the pod (under the keyswitch). One of them dam winged bastards that loves to plug up small holes with mud had been at work. I slammed the hose against the tire a couple of times to clear out the dried mud, reinstalled everything and it worked perfectly. I guess sookiesmacker wins the prize for guessing the problem. I was convinced I had checked the hose, heck I think I even posted above that it was clear. I think I was so aggrivated at myself for not being able to find the problem I just thought I had checked the hose. Thanks for everyones input. I guess it goes to show you, never give up. 






sookiesmacker said:


> Have you checked all of the vent lines on the carb??
> 
> Make sure someone hasn't routed the crankcase line to the carb also. I've seen some strange things take place when multiple people get their hands dirty.
> 
> I'm just slingin' stuff out there man.


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## hondarecoveryman (Feb 28, 2009)

Glad you got it ....and it didnt get you:haha:


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## sookiesmacker (Mar 19, 2009)

IBBruin said:


> Well, the guy came to pick up his wheeler because a friend of a friend of a friend told him he had a briggs carb kit that would fix his problem. Him, my father and myself were sitting around the night before he was supposed to leave drinking a few cold ones and I had on old carb out and apart on the bench showing them everything I had done and just generally *****ing because it was making me look like an idiot because I couldn't find the problem. I said, let's tear that sob apart one more time and take a look. I took it back off and took it apart and couldn't find anything wrong. Just for shi..s and giggles I checked the vent line that plugs into the top of the carb to vent the bowl and I couldn't blow through it. grrrrr. I was slightly inebriated so I grabbed the vent tube and pulled it out. It ended up being about 2-1/2 feet long and run up into what we call the pod (under the keyswitch). One of them dam winged bastards that loves to plug up small holes with mud had been at work. I slammed the hose against the tire a couple of times to clear out the dried mud, reinstalled everything and it worked perfectly. I guess sookiesmacker wins the prize for guessing the problem. I was convinced I had checked the hose, heck I think I even posted above that it was clear. I think I was so aggrivated at myself for not being able to find the problem I just thought I had checked the hose. Thanks for everyones input. I guess it goes to show you, never give up.


It wasn't me. You're the one who slapped the little winged suckers house out of the end of the tube. 

Glad you solved it. Sometimes mechanical issues will make you beat your head against a wall. (or at least in my case)

WHICH EXPLAINS ALOT ABOUT ME!!!!!!!!!!
:rockn::rockn::rockn::rockn:



Just sayin'


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