Really hard start in cold weather. SC Apex

[stephenpen]

My machine is really hard to start if its cold out. We left the machine outside over night and it would not fire in the morning.
If its in the garage (not heated but warmer then outside) it starts no problem everytime.
The only way I got it started was to pull the two plugs I could get at with the tools we had. Dry them off and wire brush them.
The machine sounded like to was on 1 or 2 cylinders for minute. Then another cylinder would fire til all four fired.
It took maybe 2-3 minutes on the bar with the machine coughing and back firing till it would run.
The second night I plugged in my block heater and covered the sled and I still needed to hold the throttle wide open for some time to get all 4 cylinders firing.
What is causing this. Head shim , bad plugs, fuel.

 

[mbarryracing]

What fuel are you running?
I can't tell you how many times issues like that are contributed to the fuel.
Variation pump to pump...

Sounds like it's not vaporizing, higher octane and ethanol start harder with cold air (not enough heat to vaporize). I had a car once that start very hard on premium pump, but would light right up with 87...

 

[stephenpen]

Ultra 94 octane pump gas if available or 91 at the least.

 

[mbarryracing]

You could try siphoning the tank out, get some fresh fuel from a different station (if you can) and try that. It's something easy to try anyhow.
Remember to cycle the key a few times before trying to crank, so circulate the new fuel thru the rail, otherwise you'll be cranking on the old fuel still.

Also, what spark plugs are you runnign and at what gap? That, combined with the fuel chemisty, could be hurting too.

 

[kinger]

Good call on cycling the key, I do it 3 times in COLD weather. My SC sled has started everytime, it didn't like it, the noise and stuff for the first few seconds sounds horrible but she lit and away we went after I let it warm up for about 15 mins in -15 LOL

How old are plugs? Check the gap and gap them tighter then normal. If they are a season old switching them would be advised.

 

[stephenpen]

I've had fuel from many different stations in the machine when this happens. The colder out the harder it is to start.
My plugs were wet every time. I'm running the stock cr9eb. Not sure on the gap. They looked to be gapped wide.
I have a new set to go in. What should I gap them at.

 

[mbarryracing]

0.018"

 

[stephenpen]

The plugs were in there all of last season. I'll change them out this week.
I hate changing plugs on 4 strokes.
My machine turns over no problem. It just does not want to fire up. I can tell instantly if its going to run or not.
Kinger
How many miles are you getting to a tank of gas @ 10lbs.
I'm pullied for 10lbs but I have the blowoff valve backing it down to 7 ish lbs.
I need to work out my tune before I turn it up.

 

[kinger]

Gas range? Well mine stinks I added a fuel pump and it wont suck the last gallon and half out of the tank so I need to fix that. Right now I run out at about 85 miles, then I fill up and put about 8 gallons in. I am coming up with some solutions to get 100+ mile range out of the sled without having to baby it the last 10 miles.

 

[stephenpen]

Update
I did the plugs today and what a difference.
My machine did not like any throttle till its was warm before.
Now it starts much better and runs smoother while its cold.
I gapped them to 18-20 tho. The plugs I pulled out were gapped to 30 tho.
We just need some snow