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Cold start information

Great video,
I believe the fuel mapping is more of an issue than the cranking power of the battery due to my last trip...
My first try had lots of cranking power but would not fire. I didn't try the throttle due some folks saying the fuel mapping ran it rich at start up
 

Was -17c out tonight and I went out and just turned the key without cycling the fuel pump and it started so fast that it was hard to tell if it took 3 or 4 cranks but it started fast. But.....there is always a but.... I stopped and shut the machine off and when I went to start it again I let off the key just before it started so it actually didn’t start. Tried again and had a hell of a time getting it going. It finally started the 5th try. Every time I tried it seemed the very first cranks it tried to fire and then just turned over as if there was no fuel or spark. I’ve noticed this before on a couple of other times. Next time I will hold the key on until it is good and running.
 
stomper said:
Was -17c out tonight and I went out and just turned the key without cycling the fuel pump and it started so fast that it was hard to tell if it took 3 or 4 cranks but it started fast. But.....there is always a but.... I stopped and shut the machine off and when I went to start it again I let off the key just before it started so it actually didn’t start. Tried again and had a hell of a time getting it going. It finally started the 5th try. Every time I tried it seemed the very first cranks it tried to fire and then just turned over as if there was no fuel or spark. I’ve noticed this before on a couple of other times. Next time I will hold the key on until it is good and running.
Click to expand...
A friend of mine had the same starting issue, sounded like it would start on the first or second crank and then nothing. Ended up being the fuel pickup tubes in the tank were flexing up and not getting fuel. This went on for some time, LT-X LE 16. Sled seemed to run fine after a difficult time starting.
While on bagger trips we would fill the sleds the night before, covering up the issue of his fuel pickup tubes, not realizing that the issue was still there. The other day when it happened we thought the sled was out of fuel so we put a gallon in the tank and rode to the gas station. His sled only took 5.5 gallons. Did a 60 mile loop and both our sleds took the same amount of fuel. After taking his sled to the dealer the mechanic explained the pickup tube situation.
The dealer is currently fixing the issue and we will know on the next trip if it worked. That pickup tube problem sure looked like a whole lot of other things.
 
Interesting. Keep us posted on the results. I may be wrong but I don’t think that is happening with mine as last night when this happened I only had 20km on a full tank and my fuel gauge was just off of full, but it’s something I will check out regardless.
 
A key component and variable that you guys consistently overlook is fuel... more specifically the vapor pressure or ability of the blend or batch of gasoline you pumped into your fuel tank to adequately atomize / vaporize during cold cranking / starting in very low air temp conditions.
Very highly likely that with same ECU flash but different fuel, the sled could start no issues, also the reason why it's more random on who has the cold start gremlin.
 
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So I have on older 06 Rage and first start of it when its been sitting at camp for a week and its in the - temps it doesn't want to start and Ive flooded it in the past when it didnt start. Older carb engine so nothing like what everyone on this thread is discussing. What Ive found is while Im getting things together I put a heat gun pointing on the cylinder wall for 10 min and then it fires right up. No need to put a inline or stick on block heater and have that added complexity or weight. Works well.

~ Phil
 
Perfect example of the Fuel atomization I was referring to... with cold intake air temps your fuel is just "puddling" in the intake port and cylinder and not mixing with the cold air enough to combust so you see it as wet plugs. When you added some heat, the fuel atomized enough and could ignite. Same thing happens with fuel injection, but the cause is the vapor pressure of the batch of fuel itself.
Higher octane fuels also seem to cause cold start problems in cars, need higher air temps to fully vaporize than 87 octane. As does any gasoline with a low vapor pressure... Also any fuel with ethanol amplifies the problem because alcohols require much more heat to vaporize.
 
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mbarryracing said:
Fuel atomization... fuel is just puddling in the intake port and cylinder and not mixing with the air enough to combust so you see it as wet plugs. When you added some heat, the fuel atomized and could ignite. Same thing happens with fuel injection.
Higher octane fuels also seem to cause cold start problems in cars, need higher air temps to fully vaporize than 87 octane. Also any fuel with ethanol amplifies the problem because alcohols require much more heat to vaporize.
Click to expand...
Here are my fuel choices at the pumps where I ride: 87 octane with 10% ethanol, 89 octane with 5% ethanol, or 91 octane without ethanol. Any thoughts on which of those three would be the easiest to start up in cold weather?
 
mbarryracing said:
A key component and variable that you guys consistently overlook is fuel... more specifically the vapor pressure or ability of the blend or batch of gasoline you pumped into your fuel tank to adequately atomize / vaporize during cold cranking / starting in very low air temp conditions.
Very highly likely that with same ECU flash but different fuel, the sled could start no issues, also the reason why it's more random on who has the cold start gremlin.
Click to expand...


Makes perfect sense what you are saying. So basically what you’re saying is what gas you have available in your area is going to dictate weather you are going to have cold start problems or not. All I have available is regular and premium fuel. I believe 87 and 91 octane. Which would be better? I’m running the premium 89 right now.
So then what’s the rationale behind my kids pro rmk 2 stroke firing up at -30 in 3 pulls of the cord every time. Faster rpm with the cord vs the starter on mine?
 
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What I'm saying is you could absolutely have an issue from station to station, fuel tanker load to fuel tanker load, tank fill up to tank fill up. Not all gasoline at the pumps is the same.
By nature 87 should vaporize easier in real cold air than 89 or 91... but freshness is also a factor. Stale 87 octane has very little vapor pressure (all the fiz is gone) and will start hard too.
I bet if someone did a poll on the fuel they had in the tank when they experienced cold start problems, you'd see a trend of premium octane fuels associated with it more than not...
 
I was out on Sunday with a buddy that has a new 2020 stock Winder. I noticed it didn't start very good compared to my tuned 19 which most of the time starts first try, hot or cold.
Anyway, I find these starting issues disappointing and unacceptable in today's day and age.
All our trucks and cars start perfectly down to -30 celcius, why should we expect any less from these four stroke machines?
 
74Nitro said:
I was out on Sunday with a buddy that has a new 2020 stock Winder. I noticed it didn't start very good compared to my tuned 19 which most of the time starts first try, hot or cold.
Anyway, I find these starting issues disappointing and unacceptable in today's day and age.
All our trucks and cars start perfectly down to -30 celcius, why should we expect any less from these four stroke machines?
Click to expand...


Totally agree. My 03 silverado has started to -38 without being plugged in. It was a bit stiff but it started easily.
 
last weekend my 16 with new flash started right up at 2f with last years 87 in tank. However we then filled the tanks with 91 as my buds 2 smoker requires it . 25 miles down the trail we stop. Few minutes later my sled does not crank up. Lets out nasty backfire and dies. multiple tries another backfire and then goes. Rest of weekend it started fine.
after that tank i used 87 only. my sled had horrible starting issues before the reflash this is the first issue its had since. My Batt is at 12.5 static but drops into 11s when cranked so I think ill change that just because.
 
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