My 7200 watt generator has two 240 volt outlets. Both are 30 amps. One is a 4 pin plug and the other is a 3 pin plug. I plan on using the cheaper lockout system involving 10 gauge wire and 30 amp breaker and locking connectors. Just wondering if it is possible to run both circuits to the fuse box. 30 amps are only giving me 3600 watts. Can I double that to use the full potential of the generator? Thanks in advance.
No, one outlet does the job
You're forgetting that the outlet you're talking about is 240V not 120V -- 30A * 240V is indeed 7200W, so you only need the 4 pin outlet (NEMA 14-30) and matching parts (generator-cord and inlet).
(The other outlet might be a NEMA 6-30 for 240V-only loads -- we'd have to see a photo of it to be sure. Anyway, you don't want to use it for a house hookup because it has no neutral prong, just two hots and a ground.)