Here’s my translation

Alan

Svá skal ek þjarma
I shall roughly-handle

þér at brjósti,
your chest

at hjarta þitt
so that (svá...at)

höggormar gnagi,
vipers (blow-worms) would-gnaw your heart,

en eyru þín
but (and) (let) your ears

aldregi heyri
never hear

ok augu þín
and your eyes

úthverf snúist,
turn-themselves inside-out

nema þú Bósa
unless you

björg of veitir
grant of deliverance to Bósi

ok honum Herrauð
and

heift upp gefir.
give up (the) feud (heipt) against/with(?) him Herrauðr (case?)

Ef þú siglir,
If you sail,

slitni reiði,
(let) (the) rigging break,

en af stýri
but (and)

stökkvi krókar,
hooks cause-to-drive-off (tear away?) (the) rudder,

rifni reflar,
shrouds be-rent,

reki segl ofan,
sails be-driven down,

en aktaumar
but (and) sail-braces (straps)

allir slitni,
all snap,

nema þú Herrauð
unless you

heift upp gefir
give up (the) feud (heipt) against/with(?) Herrauðr (case?)

ok svá Bósa
and also

biðir til sátta.
ask Bósi for settlements.

Ef þú ríðr,
If you ride,

raskist taumar,
(let) (the) reins be-disarranged,

heltist hestar,
(the) horses become-lame,

en hrumist klárar,
but (and) (the) cart-horses become-enfeebled

en götur allar
(but) and all roads

ok gagnstígar
and short-cuts

troðist allar
all become-crowded

í tröllhendr fyrir þér,
in troll-arms (become strewn with rocks?) in front of you (ie impeding your way),

nema þú Bósa
unless you

bjargir veitir
grant deliverance to Bósi

ok Herrauð
and

heift upp gefir.
give up (the) feud (heipt) against/with(?) Herrauðr (case?)

Sé þér í hvílu
(Let) (it) be for you in bed

sem í hálmeldi,
like in (a) straw-fire

en í hásæti
but (and) in (your) high-seat

sem á hafbáru;
like on a wave;

þó skal þér seinna
though (I) shall delay (seina?)

sýnu verra,
a worse sight for you,

en ef þú vilt við meyjar
but (and) if you want

manns gaman hafa,
to have (the) amusement of a person with maidens

villist þú þá vegarins;
(let) you then lose the-way;

eða viltu þulu lengri?"
so do you want a longer recitation? (‘Lay on, Busla!’)

Þá svarar konungr: "Þegi þú, vánd vættr, ok vert í burtu, elligar mun ek láta meiða þik fyrir forbænir þínar."
Then (the) king answers: “Be-silent you, wicked wight, and get (you) away, or I will cause to do-you-serious-harm for your evil imprecations (curses).”