If you don't already have it get Chuck Il-2 Battle of Stalingrad Guide https://theairtacticalassaultgroup.com/forum/showthread.php?t=12667
Most specs are also available on the in-game map, right side briefing hit the specs tab at the top.
Look in your keybinds for the tailwheel lock. If there's a red square there it's double bound. Hover mouse over the red square.
The IL-2 has to be flown by the gauges. In the main game menu under flight interface turn on ingame messages - technical.
Take off wide open, but as soon as you're up pull back to 90/90 and then you're on the gauges. Throttle first to 1050 mm Hg then rpm to 2050 with pitch, then adjust throttle again, check rpm. If at any time you see the "boosted mode" message you need to do something soon. Check MP (manifold pressure) first and rpm. I run it at max continuous (combat setting) all the time. Trim the plane well. Small speed changes will change the MP, if you aren't trimmed well and the nose is bobbing up and down you'll be chasing the throttle constantly. As you gain altitude the MP will fall and you can add a bit of power. Once above about 1500m you can start leaning the mixture a bit at a time till the MP starts to drop if you want to get every last bit out of it. I rarely get high enough to mess with that but if you're going above 2000 it might be worth it. Check temps of course, on winter maps you can close em up quite a bit.
It takes so long to climb you can never just set some numbers and forget about it. Once you get to cruise alt and especially if you set level stab it's very easy to have the plane speed up enough to exceed MP limits and blow the engine. Look at the gauges. MP first (throttle), RPM next(prop pitch).
Climb • Optimal climb speed: 250 kph • 2050 RPM • 1050 mm Hg Manifold Pressure • Normal Operation (Cruise) • 1850 RPM • 850 mm Hg • Combat • 2050 RPM • 1050 mm Hg • Oil radiator closed