The vin says this is a 2001?

My SIL sent this over to see if I could get it working. She had lots of spare parts, including a carb. It started real hard and took a while to smooth out.

I replaced the carb with the new one she had.

Now the starter turns but it won't start.

Neutral switch lite is lit (but even when it wasn't the starter would still turn when pressing start)

I've seen the link to the starter switch circuit in another thread - but since the starter spins - I think its something else.

Now I was bad and I did lots of other things to this at the same time:
- Remove winch wiring (winch was old and slipping (useless)
- removed/replaced reverse lever linkage in order to free the nut so it could be adjusted (reverse did not work)
- removed an aux switch which went to nowhere
- replaced front brake cables
- attempted to free up rear brake cable (I'll need a new one if I am going to get this working)

I'm about to head out and remove the carb one more time to see if I didn't get the throttle cable in the correct location - but it almost seems like there is something else stopping it from kicking over (electrical I'm thinking).

 

update: pulled the carb off and compared it to one that was on the atv when I got it.

Put it back together - and go it to run only after spraying some carb cleaner directly into the carb intake.

When it runs it is reving VERY FAST - I shut the machine off because the throttle did nothing.

The new one has a bigger opening, longer needle, longer 'throat', etc...

Is it possible that this is the wrong carb for this machine? do they make slightly different versions?

carb compare

 

First thing to do if a bike won't start is check for a spark, if you have a decent spark the problem isn't electrical, but change the plug anyway. As it hasn't run with the new carb, clean the old one out. I simply remove float bowl and jets inside it, then blow both jets and holes out with compressed air. Put this carb on, checking inlet manifold for cracks, most likely time for a crack to open is when you work on the carb. Set the valve clearances and see if it will now start.

 

Thanks.

I do have spark (I never liked doing that test - as I caught a jolt from a spark plug when I was 5/6 years old and I still feel it!) and did get it to turn over with some carb cleaner but it was reving way too fast.

I did some more searching and realized I did not adjust the bottom screw (pilot aire-fuel mix) on the carb at all and looking at the pictures I believe it is out way too far - research told me it needs to be 1-1/4 to 1-1/2 turns out from bottom.

I've put the beast under the tarp for now but may take it out tonight and try that adjustment.

- edit:
One more note - inlet manifold - there was gobs of clear silcone on the outside of the old carb where it connected to the intake manifold - so at some point I suspect someone new or thought there was a leak there. The bolts holding the carb to the manifold were finger tight - perhaps the old carb threads were stripped- I should go look at them.

 

Your new carb is way to big, it won't work properly at wide open throttle. However it may work well enough for a little "workhorse" bike like yours. Do not touch the mixture screw under the front of the carb. Idle speed adjustments should be done with the idle speed stop screw on the side of the carb. If the cable is too short the slide won't hit the stop though, so be sure the cable is adjusted to give some slack first. Only if the engine goes from a high idle to rough running and cutting out when warm, should the idle mixture screw be touched.

 

Thank you.

I will attempt to clean up the old carb and put it back in place. Knowing the replacement is wrong will save me a lot of time trying to get it to run correctly.

The ATV was my niece's. Her boyfriend and her used to ride (he had a much newer machine). She passed away in a car accident and her mother wondered if I could get it running. The boyfriend is the one who bought the 'new' carb. I assumed he had gotten the correct size.

 

I recently checked up for someone else on here about the availability of "Chinese knock off" carbs for Yam 250s, they are out there but not common, and 250 Yam carbs are surprisingly small, same size throat as many 125cc bikes, which is probably why the boyfriend got the wrong one.

 

Amazon and ebay are full of them. I only saw one that listed the throat size - and then the reviews say they ordered two and got different sizes. So - I hope the cleanout works - I have not had the chance to install it yet. (just running gumout through the jets/ports left lots of crud so I'm hoping.

Again - thanks - I can do the work of replacing but I needed to know what I was putting in was correct - or in this case - it wasn't

 

Thanks for the responses. The 20 year old ATV is back running. Shifting takes a little getting used to - but it moves forward and reverse (reverse was not working before) and idles just fine.

I'm going to check with my SIL to see what she wants to do with it. Rear brake cable needs replacing, the rear fender supports need to be repaired(weld new ends on was my thought).

 

Good to hear you got it working. Don't know about the US but good 250s are getting hard to find, and nobody seems to make a 4WD version, so it should be good to sell if SIL decides to do so. Are new 250s available in the US? Here in the UK we can't get new Honda Recons or Suzuki Ozarks at all now, not sure about Yams.