Thoughts on used trailer setup

While i was looking for 12 foot trailers for sale, i ran across someone selling a trailer plus a hot water setup and tank. A hot water setup is on my to do list… was even going to be renting one next weekend to do a commercial job. Can some of you guys tell me what you think about this deal?

Mi-t-m
Kohler 23.5 HP
General pump 5.6 GPM 3500 PSI Belt drive
Beckett 115V burner
Generator for burner
12 ft dual axle trailer with brakes
Hose reel with 200 ft of hose
500 gallon tank

$4200

He says the skid unit only has 85 hours on it. It’s been listed for a month (originally at $4800), so might could get it for $4k.

I would prefer an 8 GPM, but i was thinking maybe i could swap the pump on it out for an 8 eventually, since the engine is 23 HP? I’ve never even used a hot water unit before.

@Innocentbystander , @Racer would love to hear your guys opinions, or anyone else that might know.

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