Have you removed the EGR valve and inspected it for carbon holding open the pintle? This will cause a hard start, back firing and low power.
Ignition control device
Backfire flame arrestor
backfire flame arrestor
backfire flame arrestor
If it backfires while you are driving, the intake manifold bolts may be loose or the gasket may need to be replaced. If it backfires when you turn off the ignition, the fuel mixture is a little on the rich side.
There are several things that can cause this effect. Ignition timing out of set or worn ignition parts being a large factor. Improperly set or worn valve train being another.
A computer should not have an ignition system.
Reset the exhaust emission warning light by turning the ignition on and off 40 times. Light codes can be read by the old brake/accelerator press and turn the ignition on.
Need more info Model Year Carb TBI or MPI ignition type if altered
most watercraft are required by law to be outfitted with a USCG approved intake spark/flame arrestor.
Passenger side of the firewall, the engine computer is the ignition module.Passenger side of the firewall, the engine computer is the ignition module.
Usually when it backfires it means thath there is some kind of Spark problem! Sometimes a sticky intake valve! The first thing I would look at is the ignition system! Has it had a tune up in a while?