sx250 loses RPM

[windows1001]

I have a 2001 sx 250 on my Cobia 240 walkaround. At full throttle the motor will suddenly start losing RPM's if I back off the throttle for a second and bring it back up its picks right back up. It doesn't happen all the time and I can't see any patterns, like engine temp, fuel level etc. I have had the boat for 2 years, I have changed fuel filters and spark plugs but still the same problem. Has anyone else had this problem?

[rodbolt17]

your describing a typical symptom of loss of fuel rail pressure.
typical reasons.
dirty filter in the VST on the high pressre pump intake.
sticking inline check valve between the engine filter and the lower lift pump.
remove it,unscrew it,dump the guts, reassmble and install it.
bad lift pump or pumps, the 3.1L motors are hard on them and they should be replaced every 3 years just cause they fail.

also air leaks/restrictions in the hull systems,bad anti siphon valve or a clogged draw tube screen if used.

[windows1001]

Thanks. Where is the lower lift pump located?

[rodbolt17]

there are 3 fuel lift pumps on the port side of the motor, a defect on any of the 3 will create issues.
thats why they need to be replaced about every 3 years.
the filter in the Vapor Seporator Tank(VST) needs to be cleaned or replaced yearly or every 200 hours whichever occurs first. if its lean and you
keep runnig it lean and you may get to post about detonated pistons.
the knock sensor will only offer so much protection.

[windows1001]

Thanks I will check out the pumps. I did take care of the fuel separator.

[rodbolt17]

hi right back
welcome aboard.

[99yam40]

Hi, I am newbie.This is my frist post ...lol.
say hi to everybody.

I have a feeling you are not from the US of A.
Do you have a question or are you just feeling this site out to post some spam?