Rough Idle When Cold, Engine Wants to Quit

[vogelm1]

Bought an '07 Vector last season and have put 2,300 miles on it so far. Last year during a cold start, all I would have to do is give it full choke until fire, then half choke until the amber coolant light went out...take off choke and it would idle just fine. This year when the amber light goes off, and I take off the choke all the way, it wants to quit and stumbles if I give throttle. After it's warm it runs/transitions perfect - runs like a top. Been through two full tanks of gas (first tank had Sea Foam in it) so I don't think the carbs are the issue but could be wrong. I changed plugs at the end of last season even though they looked great. Also balanced the carbs about a week ago so rules out that. Any thoughts?

I know a lot of engines in general run rough the first few minutes, but I'd like to get it running like last season. Thanks for any suggestions!!

 

[Groomerdriver]

Bought an '07 Vector last season and have put 2,300 miles on it so far. Last year during a cold start, all I would have to do is give it full choke until fire, then half choke until the amber coolant light went out...take off choke and it would idle just fine. This year when the amber light goes off, and I take off the choke all the way, it wants to quit and stumbles if I give throttle. After it's warm it runs/transitions perfect - runs like a top. Been through two full tanks of gas (first tank had Sea Foam in it) so I don't think the carbs are the issue but could be wrong. I changed plugs at the end of last season even though they looked great. Also balanced the carbs about a week ago so rules out that. Any thoughts?

I know a lot of engines in general run rough the first few minutes, but I'd like to get it running like last season. Thanks for any suggestions!!

Well....here's what I do on my 05 and thankfully have never had any issues:

I go from full choke to 1/2 way as soon as the engine will let me. I then go to no choke as soon as the engine will let me. My sled will most times run with no choke and the amber light on.

When it's cold(er) outside (air temp) and the amber light is off, the sled might stumble a bit when you give it some gas. Once the sled is warm, no stumble.

Don't just "tap" the throttle, "give it" a little bit, especially if it's on a stand. I think the drivetrain of this 4S needs a little more oomph to losen things up. I found that if I tap mine to get it going, it has stalled...but started right up again.

I would install 3 fresh plugs now along with another "maintenance load" or 2 of Sea Foam. If that doesn't cure it, my guess is that you got a piece of junk in one of the carbs, and they'll have to be pulled and cleaned.

Something's changed from last year....and it's either a weak plug or gunked up carbs.

Let us know what you did and how it worked for you!

 

[vogelm1]

Cool. Thanks. Next time I fill up, will add some Sea Foam and see what that does. May as well try new plugs too - if that doesn't cure it, I can always pull them and keep as spares. I was hoping the carb cleaning would be a last resort, but I'm willing to tackle it if need be. From what I read on here it's not too bad/tough to do.

 

[MadMax]

One of the carbs has gummed up slightly....................... The seafoam may do the trick..... Mine did the same thing this year... The more I run it the better it has gotten. MM.

 

[Stu]

...I go from full choke to 1/2 way as soon as the engine will let me. I then go to no choke as soon as the engine will let me. My sled will most times run with no choke and the amber light on...

I had trouble with my 05 Rage on cold starts. Talked to my dealer and here is the choking sequence he gave me to use:

1. Start cranking BEFORE using the choke.

2. Gradually add choke until the engine begins to catch (ends up around 1/2 choke or so)

3. Once the engine is started, back the choke off as quickly as possible without stalling (for me it seemed easiest to watch the RPMs and as they started to rise back the choke off to keep the it around warm idle or lower)

My sled usually will idle longer with the choke off than on waiting for the amber light to go out.

 

[SIMMER]

I had the same thing on my RX1 this season. The carbs were all messed up and I even added SeaFoam to stabilize in the Spring last season. Had them cleaned up, and I mean taken apart and everything cleaned individually, and then it ran like a top. Cost me $200 because it was for sale and I couldn't show it to anyone the way it was.

If I had carbs again, I would drain the float bowls at the end of the season and never look back. 2 out of 3 seasons I had troubles no matter what I did in the spring. SeaFoam, Stabil.....none of that stuff helped.

 

[az99]

If I had carbs again,

Good point. When is Yamaha going to step into the 1990's and start putting fuel injection on everything. Carbs are for antiques and race cars.

 

[vogelm1]

Thanks for the tips and hints guys...will try them one by one until we get 'er fixed up right.

 

[Wildman]

Chances are your pilot jets are gummed up a bit. The only way to cure that is take the carbs off and clean the jets. It only takes an hour at the most. I just did my Rage tonight because it was stumbling when cold. No problems after cleaning the pilot jets (which have a very tiny inside diameter). Then sink the carbs and she'll be like brand new.

 

[rough rider]

idle

When I store my sled for summer i suck out all fuel from tank and then i take 2 gallens of premium and mix with klotz octane booster and run that through sled keeps carbs super clean all summer, another thing that works is to mix gas half and half with avaiation fuel, and run that threw carbs, seems that whatever additives are in the klotz or avaiation fuel really resist turning green and plugging up carbs.

 

[jmanz]

I bought a brand new 07 Rage GT last season and had the same issues with 0 miles on the clock. Bought it before snowfall and wanted to hear it run in the garage and couldn't keep it running. Took it back to the dealer and showed him what happend. He adjusted the idle because it was too low, but told me to use this sequence. Full choke until amber light goes out, then half choke for about 10 minutes then it should be good to go. Actually worked on the trails when I took it out. I also had the stuble if I blipped the throttle which when away when it was warm. That sequence was for the first morning start of the day. I found I needed no choke the rest of the day.

 

[Crewchief47]

When is Yamaha going to step into the 1990's and start putting fuel injection on everything. Carbs are for antiques and race cars.

Ummmm, Apex, FX Nytro, FX Phazer and for 2009 the Vector and Venture are FI. So I would have to say that about covers the line-up.

 

[Groomerdriver]

When is Yamaha going to step into the 1990's and start putting fuel injection on everything. Carbs are for antiques and race cars.

Ummmm, Apex, FX Nytro, FX Phazer and for 2009 the Vector and Venture are FI. So I would have to say that about covers the line-up.

ummmm...then Vector is not FI'd

 

[MadMax]

Re: idle

When I store my sled for summer i suck out all fuel from tank and then i take 2 gallens of premium and mix with klotz octane booster and run that through sled keeps carbs super clean all summer, another thing that works is to mix gas half and half with avaiation fuel, and run that threw carbs, seems that whatever additives are in the klotz or avaiation fuel really resist turning green and plugging up carbs.

That's the right combo according to a local repair shop owner....... He said he's tried all combo's with the best results from this...... He laughs about using stabil... He's made "LOTS" of money from sled owners that use stabil. MM.

 

[az99]

When is Yamaha going to step into the 1990's and start putting fuel injection on everything. Carbs are for antiques and race cars.

Ummmm, Apex, FX Nytro, FX Phazer and for 2009 the Vector and Venture are FI. So I would have to say that about covers the line-up.

They are discussing a Vector. Look at the specs the 2009 ER is still not fuel injected. My statement "fuel injection on everything" should lead you to believe that I know they have injection on some models.