Aq225 bogs at half throttle.

[bryceheinz]

Boat is an 85 bayliner. Just replaced carb to rule out an issue and I am having the same problem. She starts and idles fine and runs smooth at no wake speed. When I bring it up near half throttle I can hear it sputtering and if I try to accelerate more it bogs and backfires. I have new plugs,wires,cap and rotor as well as a pertronix ignition and new coil. I also replaced my fuel filter. The only thing I haven't replaced is my fuel line which is original and is uscg rubber. Is there is screen in the tank? The boat is a 85 bayliner Ciara 2450.

 

[pooley]

When you accelerate are you seeing the fuel squirt into the carb? Have you adjusted the fuel/air mixture screw?

 

[bryceheinz]

Not really skilled with carbs. What are the factory settings for the screws? I haven't looked to see. It backfires through the carb so I don't really want to put my face near it. I'm going to replace fuel line tonight.

 

[pooley]

Almost seems like it running to lean?
Are you running cheap fuel?
How is the engine temp?

 

[bryceheinz]

Engine temp never raises unless I'm cruising. New thermostat last year. Fuel is whatever the marina sells. I'm going to replace plugs and fuel line tonight and get a visual inspection of tank with a scope.

 

[bryceheinz]

Ok so I took an inspection camera down to the dock tonight and found that my fuel tank was bone dry even though my gauge said 1/4 tank. I added fuel and it started with the new used carb I put on. Within 1 minute the engine started flooding to the point of it knocking and eventually died. I replaced that carb with the automotive carb I had and it runs perfect. So I now have two volvo marine quadrajets that both fill the engine with gas and cause it to die and one auto quadrajet that works perfect. Any ideas?

 

[Maclin]

Fix one of the marine ones I guess. Need to find a better source for obtaining carburetors maybe.

 

[bryceheinz]

I need to check compression. I think based on the cfm of the marine carb they flow too much for my old engine causing it to flood since it cant burn off all the fuel its getting.

 

[Maclin]

I need to check compression. I think based on the cfm of the marine carb they flow too much for my old engine causing it to flood since it cant burn off all the fuel its getting.

That is not the problem since you say you have raw fuel dumping into the engine. The fuel pump output should be stopped at the carb inlet needle/seat valve when the fuel bowl is full and should never just dump raw fuel into the engine no matter what CFM the carb is rated at.