Crusader 270 falling on its face

[ataylor233]

Hello all, i have an older Carver 3207 with twin Crusader 270's ive replaced both Distributors with sierra 18-5494-2
.. port engine runs great Starbord engine when underway after 3k rpm seems to spudder and drop the rpm to around 2500. when this happens i pull thr trottle down a bit then i can push it back up to 3k rpm.... i set both engines to 10 degrees btdc could this be a fuel issue i've added an additional fuel filter to both engines over the stock.This engine also has a new carb purchased last year. not sure if it needs to be tuned or cleaned .. this is annoying ... any advice or am i missing something?

[bud37]

What brand carb is on that engine and was it brand new when installed. A new one should be fine, always check the float height before installing/with new gaskets etc. You shouldn't need two fuel filters for each, perhaps a restriction there.

Is the fuel pump electric or mechanical ?

[ataylor233]

Source of the post What brand carb is on that engine and was it brand new when installed. A new one should be fine, always check the float height before installing/with new gaskets etc. You shouldn't need two fuel filters for each, perhaps a restriction there.

Is the fuel pump electric or mechanical ?

Mechanical fuel pumps fuel water separators are in addition to the stock filters on the back of the engine.

[g36]

What micron fuel filters were added? Could be a issue if too fine. Distributor advance or Wonder if the carb secondaries are opening correctly

[buster53]

Have you checked to make sure there is no water in your fuel?

[km1125]

How long are you running "underway after 3k rpm" when it "seems to spudder and drop the rpm to around 2500"??

Sounds like a typical fuel restriction. Could be plugged filters somewhere, or an anti-siphon filter that needs to be cleaned or replaced. Could also be a plugged vent on the tank on that side.

[ataylor233]

ok still having this issue but i narrowed it down to two things. carb or fuel pump. while someone else was driving i was looking down at the carb while cruising i pushed the throttle to 3k rpm it went fine then after about 1 minute i noticed that one side of the carb was spraying fine the other side started to spudder a bit.. so i figured its either not getting enough fuel or something is wrong with the new carb... Today i'm replacing the fuel pump.

[km1125]

Too bad you don't have a gauge on the line going to the fuel pump, and one from the fuel pump to carb.

A restriction prior to the fuel pump is going to cause the pump to need to work harder to deliver more fuel when you need it under load and higher RPMs). A new pump might "fix" the issue, only because it's a little more capable than an older and worn one, but isn't really resolving the actual problem.

Did you ever absolve the anti-siphon valves? They are frequently an issue when fuel delivery becomes a problem.