Truck Repair: fuel filter, canister type, secondary fuel

Question
how to change a secondary fuel filter> Does it spin off or unbolt? ISB 300 engine In a Motor coach.

Answer
The one most have that bolt to the engine are a canister type filter with the part number of the element on a sticker on the outside of the canister.The top unscrews off of it and has an o ring on the top.Some do have a small spin on filter located in the same place.The filter I am talking about usually is mounted to the cylinder head behind the intake connection.Some rare occasions the motor home manufactures mount it somewhere where you can actually get to it easier.The plastic top canister takes a 1 1/16" or 1 1/8" socket to get it off.