Backfire Issue

Hello All,
First post and all of that.

I have a 3607 Carver with twin 454 Crusaders. Port was changed 200 hrs ago and starboard indicates 1300 hrs. Underway, I am getting a backfire through the starboard engine. I understand this is possibly a lean condition. Question is: Where are the fuel filters on this boat? Are we talking about the small cartridge where the fuel line enters the carb, or something else?

Is it backfiring thru the exhaust or "spitting" thru the carb? The plug wires & cap are easy to replace & can cause both conditions. Might as well change the plugs as getting the wires off is the hardest part. Pay attention to how the plug wires are routed as that can cause crossfire.

The early setup had a paper cartridge fuel filter (before the pump) and the screen inside the quadrajet...we took ours out as the builder had racors installed (and the can rusted thru)...the newer engines have a water separating filter as standard equipment...

makomark said:

The early setup had a paper cartridge fuel filter (before the pump) and the screen inside the quadrajet...we took ours out as the builder had racors installed (and the can rusted thru)...the newer engines have a water separating filter as standard equipment...

Click to expand...

I have an aluminum tank on either side of the boat that I am assuming is fuel. The line runs from the tank to a fuel switch under the steps, towards the rear. I suppose my biggest question is: Where are the filters physically located on this boat?

The cartridge filter I referred to previously is on the Starboard side of the engine, in the vicinity of the breaker box, assuming you have an in-line gear....follow the inlet line of the fuel pump aft until you get to the cartridge.

Update

The filters are in a canister under the coil. Both had water in them and both filters were dirty. The starboard filter had a black ring around it. The starboard filter was metallic while the port was a fiber material.

After changing the filters, we turned on the blower for awhile, then fired em up. The port side started with merely a bump of the starter while the starboard finally started. Starboard ran smooth for about 10 seconds, then died. Tried to re-start but no. The mechanic said the fuel pump was out. Will be replacing the fuel pump tomorrow and let you know.