Throttle Needed on Start Up

[ThatOneGuy'sBrother]

I’ll tried to bring motor to normal operation temperature 168 f by holding throttle and then as soon I’ve released it engine dies. I didn’t try to run / drive sled like that. After I replaced spark plugs motor started immediately and stayed idling. It didn’t happened again in 900 miles.

We are in the UP right now. No spark plugs and 5 hours from home. We just rode it till it would stay running. Started fine this morning. Still taking it in. They will make a case with Yamaha. Guessing nothing will be found or fixed. But Yamaha will at least know about it.

 

[jonlafon1]

In 11500 miles I have never touched my throttle to start my sled. Now the guy I ride with has a viper and has had plenty of issues starting. Valves were worked on also and it was slightly better after wards. Hope you get it figured out. Should never have to touch the throttle ever when starting. It should be running on all 3 cylinders at all times also. I ALWAYS shut mine off with key not kill switch. Replace plugs every year..

 

[ThatOneGuy'sBrother]

In 11500 miles I have never touched my throttle to start my sled. Now the guy I ride with has a viper and has had plenty of issues starting. Valves were worked on also and it was slightly better after wards. Hope you get it figured out. Should never have to touch the throttle ever when starting. It should be running on all 3 cylinders at all times also. I ALWAYS shut mine off with key not kill switch. Replace plugs every year..

This is our first season riding it. We bought it as a leftover. So it still has the factory warranty. If they do find anything we will not have to pay a deductible like you do with YES.

We have about 1,800 miles on it now. It has done this about 5 times. What sucks is it probably will not do it at the dealer. So it will not get fixed. None of the other sidewinders that we ride with have ever had this issue.

I generally never change spark plugs that often on a 4s. My 15 apex has 10,200 miles on it right now and i have never even considered spark plugs. But it always starts. Even at -40°f.

 

[Crossfire12]

It’s Yamaha dna in these motors!

 

[jonlafon1]

This is our first season riding it. We bought it as a leftover. So it still has the factory warranty. If they do find anything we will not have to pay a deductible like you do with YES.

We have about 1,800 miles on it now. It has done this about 5 times. What sucks is it probably will not do it at the dealer. So it will not get fixed. None of the other sidewinders that we ride with have ever had this issue.

I generally never change spark plugs that often on a 4s. My 15 apex has 10,200 miles on it right now and i have never even considered spark plugs. But it always starts. Even at -40°f.

5 times is to many! I have seen exactly what you describe on Vipers.. Common actually.. The valves were to tight on some years of the Viper motors right from new..

 

[jonlafon1]

This is our first season riding it. We bought it as a leftover. So it still has the factory warranty. If they do find anything we will not have to pay a deductible like you do with YES.

We have about 1,800 miles on it now. It has done this about 5 times. What sucks is it probably will not do it at the dealer. So it will not get fixed. None of the other sidewinders that we ride with have ever had this issue.

I generally never change spark plugs that often on a 4s. My 15 apex has 10,200 miles on it right now and i have never even considered spark plugs. But it always starts. Even at -40°f.

What dealer are you going to with it if you dont mind me asking?

 

[cannondale27]

Also you should never be paying a deductible for Yamaha warranty whether initial or YES. If dealer wants that look for another dealer.

 

[sideshowBob]

I think the need for throttle on start and poor idle is most likely spark plug related.
I had this issue once after the sled had sat for a while and I started in at -25c and I made the mistake of stopping cranking it when it first fired and of course it quit. It did eventually reluctantly fire up but only on two cylinders. Luckily once it warmed up it cleared itself and never happened again.

 

[0degC]

Our 2020 winder has the same issue! Certain times starting it acts like the mapping is way off. You need throttle to get it started. Once its running it needs throttle to stay running. After a half hour of riding it will run like normal. Some times when starting it also only runs on 2 cylinders. After 5 minutes of warm up it picks up the dead cylinder and runs fine. Will be taking it in as its less than a year old. But i doubt they will find anything.

Is your sled stock? Or have an aftermarket tune on it?

 

[Rtbo]

I’ve had your problem, needed throttle to fire up. I brought it to the dealer a couple years ago and they couldn’t pinpoint what was wrong and they changed plugs, fuel pump, fuel regulator the little return elbow going into the tank and I think I’m missing something else. The fuel pressure was too high. I told them about the return elbow at the tank and they said that wasn’t it but after they changed it the sled ran fine, coincidence? I think that elbow was changed by Yamaha after 17 or 18 though.

 

[Motorhead]

I’ve had your problem, needed throttle to fire up. I brought it to the dealer a couple years ago and they couldn’t pinpoint what was wrong and they changed plugs, fuel pump, fuel regulator the little return elbow going into the tank and I think I’m missing something else. The fuel pressure was too high. I told them about the return elbow at the tank and they said that wasn’t it but after they changed it the sled ran fine, coincidence? I think that elbow was changed by Yamaha after 17 or 18 though.

Almost my exact situation, they replaced so many items it was crazy to see the list. All of what you wrote plus more was checked and replaced.

But mine only happened if it was cold, and if I was starting it for the first time that day. In fact, I had dropped off my sled at the dealers for 2 weeks because of out of town work schedule. Upon returning home I called, only to find out they could not find any problem with it. They had started it daily sometimes multiple times, and it started fine. Problem was, we had a 2 week spell of unusually warm weather, so again I stated “It only happens when it is cold and at first start only” for that day. So as luck would have it, the weather turned much colder that night for an extended period, so when I went to pick it up and start it, It wouldn’t start without 1/4 throttle, and then when it did, it acted like it was chocking out. Let go of the throttle and dead again, and of course it would have taken a 15-30 minute ride for it to run normal again. Brought the head service tech out and let him try and he was amazed! They had it for another week or more and once they repaired my problem, I felt better about getting an upgrade tune which I wanted. Went from eco to Max Spool 16 and never looked back since.

I’ve read a bunch on here about moisture in different lines freezing, which made sense to me, but whereas I had the 5 year warranty, which I have used 3-4 times, I just dropped it off and let them do the diagnostics or component swap outs. My bet was moisture problem but they did not agree and referenced many replaced parts and high fuel pressure problems again. Have had 2 of those replaced, but they did a great job whereas, on third season now since last fix.

 

[0degC]

I’ve had your problem, needed throttle to fire up. I brought it to the dealer a couple years ago and they couldn’t pinpoint what was wrong and they changed plugs, fuel pump, fuel regulator the little return elbow going into the tank and I think I’m missing something else. The fuel pressure was too high. I told them about the return elbow at the tank and they said that wasn’t it but after they changed it the sled ran fine, coincidence? I think that elbow was changed by Yamaha after 17 or 18 though.

Coincidence nope. Most fuel is returned to tank at idle through this elbow, it is very restrictive and can be drilled out. This is a requirement with the aftermarket kits with the big fuel pumps. But if stock I would drill out anyway, this well lower idle fuel pressure a bit and lean out. This problem in general is rich at idle or a fouled plug.

 

[ThatOneGuy'sBrother]

Is your sled stock? Or have an aftermarket tune on it?

Completely stock.

 

[ThatOneGuy'sBrother]

Also you should never be paying a deductible for Yamaha warranty whether initial or YES. If dealer wants that look for another dealer.

I have never gotten to use warranty on any new Yamahas. Ever since my local dealer closed i have had no luck getting anything covered. But i have always been notified there is $100 deductible per failure with YES coverage. And if it is not covered you pay for all the time they took to figure out it wasn't covered.

 

[Motorhead]

I have never gotten to use warranty on any new Yamahas. Ever since my local dealer closed i have had no luck getting anything covered. But i have always been notified there is $100 deductible per failure with YES coverage. And if it is not covered you pay for all the time they took to figure out it wasn't covered.

That really sucks!
I have used mine many times, Hell they even paid for my first blown belt because of worn secondary rollers in under 500 miles when new. Back then I was trying hard to get 10 miles per gallon out of my sled. Dealer told me I should see much better then that, bring it in. So I finally did and it was found to be my first fuel pressure regulator and they adjusted clutch alignment. Gained 5 mpg after that. So I cannot say anything bad about my dealer. Not one penny from my pocket ever for warranty items or work, and I have had quite a few!

That 5 year warranty was a deal back then.