Narada Purana (Jyotisha Selections) · by Vyasa
Chapter 6 · Calendar, Muhurta Elements
कालमानं मुहूर्ताङ्गानि च
ज्ञः स्वायार्यष्टखायेषु जन्मतश्चेन्न विध्यते ।धीत्र्यकादिगजांतस्थैः शशांकरहितैः शुभैः ॥ २७४ ॥
In the full Narada Purana (Purva Bhaga) this is chapter 56, verse 274.
Mercury is good from the birth sign in the 2nd, 11th, 6th, 8th and 10th, if it is not blocked. Good planets other than the Moon block it. They block from the 5th, 3rd, 9th, 1st, 8th and 12th.
Simple meaning: Mercury is good in the 2nd, 6th, 8th, 10th and 11th, unless other planets block it.
जन्मराशेर्गुरुः श्रेष्ठः स्वायगोऽध्यस्तगो न चत् ।
Jupiter is good in the 2nd, 5th, 7th and 11th, unless planets in blocking places stop it.
जन्मभादासुताष्टांकांत्यायेष्विष्टो भृगोःसुतः ।
Venus is good in most places from the birth sign, unless planets in blocking places stop it.
न ददाति शुभं किंचिद्गोचरे वेधसंयुते ।
A blocked planet in transit gives nothing good, so check the blocking first.