496 H.O. and Boost pump
 

I had some issues this season with the engine. It would start fine and idle fine but on take off it would get to roughly 2600-2800 RPM's and sputter and back fire. I then back off the throttle and would continue for another second or two and return to normal idle. I tried this take off several times with same result even varing how quick I would try the take off. After a trip to mechanic and a water test he tested the power going to the boost pump with nothing reading so assumes this is what the problem is and will fix for $350. So my question is does this sound right as far as a problem to the symptoms? It just seems odd that en engine with 100 hrs would have an issue with a boost pump or an fuel pump in general. He also suggested that the regulator be changed also. I am not sure what the regulator does but should it be changed as well?

i call bull **** on the pressure regulator,,,unless he tested it with the gage,,,,

I had the exact same thing happen to me a week ago. The motor ran fine at idle, but as soon as you to get up on plane it would "pop" and back fire, and fall off plane. It always started right back up, but unless you cycled the key a number of times to fill the water separator, it would not attempt to take off and run. My local mechanic told me to check the fuel tank pick-up tube, the anti-reversion fuel ball, or the lift/boost pump. Everything checked out but the boost pump. It appeared weak. I bought a new Mercruiser unit for $225, installed it, and the motor runs perfectly again. Also, my motor has just 48 hours on it, so it can happen. You can also test the fuel pressure on the shrader value next to your antifreeze tank. You should have 40-44lbs pressure at that point to run properly.

Thanks for the info tucker....sounds like this is it. Do you remember which part number it was....861155 A3 or 861156 A1

I had a bad booster pump on my 496 right out of the gate. Same symptoms. We hooked a gauge up and as soon as I would try to come on plane the pressure would drop to around 17 PSI. Pump is easy to change out.

Quick Silver # 861155A 3. Retail was $249.00 according to my dealer. He gave me a deal at $225.00. I was able to install it easily myself. After installing I checked the fuel pressure and had 42lbs at the fitting. Boat runs perfect now. I was told to make sure to fill the fuel sepperator with fuel prior to start up, as it make the boost pump prime easier??? I followed that advice and mine started right up, and ran great again.