[Digicypher]

Hi Everyone,
I have an 03 600 Sportsman with about 960 miles on it. It has been garage kept and in great shape except for the fact I left the gas on and could not ride it over the summer. Fast forward to last weekend and I could not start it up unless I feathered the choke a lot. I got a rebuild kit and put in the new(supposedly the same jets as came on the bike) parts, tried to start it up and had fuel and a little oil come blasting out of the head into the air box return(smaller tube). I was not the one who took the carb out in the first place( I learned that lesson fast). I was hoping that someone could help me out and post a picture(s) of what tube goes where on the carb as far as the fuel line and such to help me figure out what happened. It is a OEM Mikuni carb. When I looked at it before stripping it down to remove the carb it looked like the fuel line from the pump(there is 4 lines from the pump) which had the heat shield wrapping on it went to the left side towards the bottom of the carb. Then there was the bowl drain from the bottom of the bowl which has a screw to remove water from the bowl(the tube was clear). There is/was another clear tube with a small radius curve in it that went I thought towards the top of the carb. I have looked at the service manual and it does not give or show this information clearly. If someone would be so kind as to help me with this info I would be so grateful! Also, In the service manual there was supposed to be information on how many turns out the needle valve and such are supposed to be backed out that I could not find. There was supposed to be an addendum page(s) with all the factory screw setting and such that I guess I am missing. Thanks for helping me in advance!

 

[latebird]

Page 1.8 of the service manual that I have specifies the fuel screw at 1.5 turns out from lightly seated.

 

[Digicypher]

Latebird,
Thanks for the reply! I do not have this page in my manual. I have my fuel inlet valve connected to the fuel pump correctly. I see the "vacuum to fuel pump" connection on the left side of the picture. Where is this supposed to be connected to? As far as I know on mine there was no connection to this port? Nor was there vent lines "teed" together?

 

[latebird]

The picture is typical - I looked up your specific carb - on your carb, one vent port and the vacuum port are capped off (#12 in the pic) - your fuel pump gets it's vacuum from a port on the cylinder head

 

[Digicypher]

Ok, so what would cause it to blow gas and some oil out of the head into the box? Any ideas?

 

[latebird]

Oh - that's easy - when the fuel is left turned on, it will overflow the carb, seep past the intake valve and piston rings to fill the crankcase - when you crank the engine over the excess fuel/oil will blow through the crankcase vent back to the air box - usually just an oil change will correct that problem - it holds 2 quarts, so drain the oil into a 5 or 6 quart pan, change the filter, put in 1.5 quarts, start the engine and let run for about one minute, shut off, wait at least 3 minutes and top off the oil. It may take slightly more or less than 2 quarts.

 

[Digicypher]

You are a plethora of information today! Does your manual tell you what the screw settings(how much they need to be backed off) for the needle valve and such? I am going to dig into it tomorrow morning, take the carb out and go through it to check everything out. I was reading about the membrane on top of the carb had to be installed with a tab going in a certain direction? Why would this be? Again, sorry for all the questions.

 

[polman500]

" I was reading about the membrane on top of the carb had to be installed with a tab going in a certain direction? Why would this be? "
Because it won't fit any other way.

 

[latebird]

Perhaps if the jet block assembly (#9 on the breakdown) were installed backwards then the tab would not align and the jet block would need be turned around? I don't know if that's even possible because I have never removed the jet block, but it's hard to say what some aspiring young mechanics might be capable of.

 

[Digicypher]

I will be working on it tomorrow morning and give an update. I plan a taking it out and rechecking everything installed and done.

 

[Digicypher]

I did an oil change with new filter and I can get it to crank. The gearbox was full of fuel. Now I've got to figure out why it is back firing a lot and it dies when I give it just a little throttle (no choke). I'll lool at the plugs tomorrow and go from there..

 

[polman500]

Check throttle cable free play and the ETC switch.

 

[Digicypher]

Etc. Is 6hat on top of the handle bar?

 

[polman500]

Yep, Electronic Throttle Control

 

[Digicypher]

Well, after tinkering with it for 3 hours today I am happy to report she's purring like a kitten! She's idling at about 1250 rpm, got power all rhe way through with some to spare. I downloaded the service manual again and this copy had what I was missing on the first one. I started from scratch and adjusted one thing at a time till it all fell into place. She runs better than when I got her second hand in 04. Thanks for all the help and guidence offered! I've not worked on an ATV carb lime the Minuni before. I learned more than I ever really wanted to know about this one haha. Have a great Christmas everyone!