Simple. Turn the key on an off 4 times to cycle the fuel pump. Start the engine with the throttle cracked slightly open, and keep the key in the start position until it catches. DO NOT let the key off until its running.
This when its really cold.
I also went to a bigger battery and an AGM battery.
I went up to a 310cca series 20 agm.
It fits in the battery box with the foam removed.
Sled rolls over much faster regardless of temp and has the balls to do the job when really cold.
There are 2 probs when starting 4strk sleds in severe cold.
1. They don't roll over fast enough.
2. They flood easily as the ecu throws major fuel sensing the ambient temp and the slow roll over doesn't allow the engine to catch either soon enough or at all.
Result is flooded motor.
The fuel system gets primed when the key is turned BEFORE rolling over the starter. Its that lil cycle you hear when turning the key on.
If you try rolling the motor over before the cycle is done there may not be enuf fuel to catch....
You should always let the cycle complete before rolling over the motor...even when its not crazy cold. But if you don't do it when really cold you are asking for flooding.
When its really cold turn the key on/off a few times BEFORE rolling the sled over...insures the injectors are primed and get a good initial squirt.
The other trick is to keep the starter rolling when the motor is struggling to start....helps it catch as well as provides a bit of air along with the super rich fuel that's being introduced.
The trick of slightly opening the flipper while rolling over also helps to provide some air while the sled is having the super rich fuel introduced and rolling over slowly.
You wont hurt the starter or motor by leaving the starter rolling a lil longer till the motor fully catches....and make sure to leave it rolling till the motor fully catches...not just coughs...
When its really cold you only have a couple tries before it will flood.....then grief.
Cycle the key on/off a few times.....roll the sled over until the motor catches...if it isn't catching DONT let off the starter...keep it rolling and open the throttle a bit and keep it rolling till it starts.
This will usually always do the trick IF you have a strong battery.
And NEVER shut the sled off ntil it fully warms up...especially when its really cold...you run a high risk of fouling a plug(s)