Engine run in with cowl removed on Mod. IV?

[beeryboats]

I'm so close to starting this engine I can almost smell the exhaust. Would you recommend I put the cowling on to do the break in run? With the upper cowl also being the dash or panel cover it looks like it would be very windy without it in place.

Also, any tips on priming the fuel system?

[Av8r3400]

I've ran my IV with the cowl off many times. As long as it doesn't start raining, you're fine.

[HighWing]

I agree with Larry. Not an issue, though I have never run it to Max RPM - maybe up to 3500 for short periods.

[TY2068]

I've run mine at low rpms to check for leaks after changing hoses-lines or while making multiple adjustments. For max rev tests I'd put everything back on. You can monitor the engine temp with "normal" air flow and have piece of mind something isn't being lashed around by the blast.