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QUOTE(Blu @ Aug 14 2009, 04:26 PM) <{POST_SNAPBACK}>Hi,
I'm having trouble tracking down an engine issue. Boat is a 1986 Sea Ray with a 5.0L 230HP mercruiser engine.
The problem is that the boat will only run above 3000 RPM for about 10 seconds before it starts to hesitate and buck. I don't hear an electrical miss. Watching the tach - I will see it drop several hundred RPM and then bounce back up and all over until I drop the throttle back and get it under about 3000 RPM. The water seperater/fuel filter only has about 20 hours on it. The in-lin fuel filter is brand new and the cap/rotor/wires/plugs all look like new.
Can a fuel pump just get weak or something? Any suggestions?
Thanks for looking!
How old is the gas in the tank. Filters and seperators won't always get water and/or dirty gas. The first place I look with those symptoms is the gas itself. If it isn't fresh ie. a fair amount of gas run through the tank It is worth checking. Contaminated gas can clog filters quite quickly.
I did have a coil wire crack that also produced similar symptoms on the same engine you have so after gas look to ignition. Fuel pump wouldn't be my first guess as it seems you are pumping fuel fine up to 3000RPM and should maintain enough fuel pressure in the lines.
I start with the simple fixes and then look elsewhere if the problem isn't found. Hope you find the issue soon enough.
I'm having trouble tracking down an engine issue. Boat is a 1986 Sea Ray with a 5.0L 230HP mercruiser engine.
The problem is that the boat will only run above 3000 RPM for about 10 seconds before it starts to hesitate and buck. I don't hear an electrical miss. Watching the tach - I will see it drop several hundred RPM and then bounce back up and all over until I drop the throttle back and get it under about 3000 RPM. The water seperater/fuel filter only has about 20 hours on it. The in-lin fuel filter is brand new and the cap/rotor/wires/plugs all look like new.
Can a fuel pump just get weak or something? Any suggestions?
Thanks for looking!
How old is the gas in the tank. Filters and seperators won't always get water and/or dirty gas. The first place I look with those symptoms is the gas itself. If it isn't fresh ie. a fair amount of gas run through the tank It is worth checking. Contaminated gas can clog filters quite quickly.
I did have a coil wire crack that also produced similar symptoms on the same engine you have so after gas look to ignition. Fuel pump wouldn't be my first guess as it seems you are pumping fuel fine up to 3000RPM and should maintain enough fuel pressure in the lines.
I start with the simple fixes and then look elsewhere if the problem isn't found. Hope you find the issue soon enough.