lean backfire on accel perf pass problem

[tgrant11]

I was hoping I could get some help on my friends boat. It is a 2002 response with the hammerhead and seems to have a lack of power and cutts out and backfires from the intake under heavy load. He also has a problem with his perfect pass where the display screen flickers. The other speedo for the boat happens to be about 10 miles over what he is actually doing. I have done a full tune up including plugs wires cap rotor and fuel filter. This didn't change anything. I have been reading other posts where people have been talking about fuel pump screens becoming plugged so I plan to check fuel pressure today and possibly check that inlet screen. I was also wondering if anyone could tell me where the dlc is located on this boat?? Any help would be greatly appreciated. Thanks Tony

[bigD]

Can you check the ignition timing is it adjustable on this boat ?

[tgrant11]

Can you check the ignition timing is it adjustable on this boat ?

I checked the distributor to see if it was tight and it was. Most likely that would indicate the timing would still be set right. No guarantee but I pulled the fuel pump today and found the screen in the inlet was completely plugged with sand. Cleaned that out and will test drive tonight.

[martinarcher]

I bet that was it. I had the same issue last fall. New fuel pump fixed mine - I found the vent line blocked while changing it(mine is manual not electric like yours). I threw a permanent fuel pressure gauge at the rail for future use or problem solving while I was at it.

[tgrant11]

I bet that was it. I had the same issue last fall. New fuel pump fixed mine - I found the vent line blocked while changing it(mine is manual not electric like yours). I threw a permanent fuel pressure gauge at the rail for future use or problem solving while I was at it.

The fuel pump was very loud yesterday and now is very quiet. It still has a lack of power and backfires from intake. I found some black stuff inside the pump after pulling the screen and cleaning it. I am guessing that was plastic from the impeller and it may need a new one. I am looking to find the pump aftermarket do you know where I could find one a little more reasonably?

[martinarcher]

Bakes online could get you a pump. If I remember right I got mine from iboats.com (they had a nice exploding diagram for all the engine parts on my boat). I have heard others recommend skidim too.

[tgrant11]

The problem ended up being the fuel pump. The screen was plugged with sand and didn't provide enough fuel at the inlet. Even after cleaning the screen at the inlet, I found the pump only producing 37 psi at idle and when you punch it, it would go down to 10. That is when it would backfire and not produce the power it would require. After replacing the pump it had 45 psi at idle and went up to over 50 while on the gas.

[martinarcher]

Sweet. Glad to here it's back running at full power. That lean backfire happening just when you need full power can get annoying really fast! I was sure glad it went away with the new pump.