225 twins, port engine starving at low RPM

I have a 2003, 225 4 stroke that acts like it is starved for fuel at low RPM. I have replaced the fuel line, bulb, water/fuel separator and the filter on the engine. The engine will idle OK until I give it some throttle then it chokes down. The only way to get it up to speed is to have someone pump the fuel bulb and then get it above 3000 rpm ASAP??? What am I missing here?
Gravy

[boats.net]

If it runs as long as pumping primer bulb then could be bad fuel pump , air leak in fuel hose leading to pump or a fuel restiction in fuel hose or fittings.

gravy, I have same engine, just acquired in April, with same problem. I have done everything you have done and have not made the commitment to replace low pressure fuel pump. My LP fuel pump comes on some of the time (I can hear it cycle about every 20 seconds) but I am not sure it is cycling on when I have the problem. Engine runs great above about 3500 rpm.

Through my own stupidity I put a tank of 10%ethanol fuel in that matched up for when my problem started. Not sure that was part of the problem or just coincidence. Let me know if you fine the "cure".

[jb123]

check motor filter when this happens..if it is more than 3/4 full more likely a bad lp fuel pump, unbolt pumps, pump ball, if gas comes out of rear port, replace. if its half or less full,maybe a bad seal at filter, air leak or supply restriction as boats.net said.

fuel is right at cartridge level on fuel filter when this happens which sounds like the threshold you mention. Sounds like I have a new project for the weekend. Thanks

Thoughts on the best place to buy a LP fuel pump if I need one??

[Dennisg]

I have the same thing as you,twin F225's Manufactured in 2003, and have had the exact same problem. It is the low pressure fule pump. replace it on both motors and no more problems. I also added Marvel Mystre oil to the gas, as long as there is e10 gas in the tank, add 1 oz. Marvel Mystre oil for every 5 Gals. of gas and no more problems with e10. Also add gas stablizer according to directions on the container. The Pump is easy to get at, a easy job to replace.
Dennis

[jb123]

OOPS my bad... i didnt notice these were 4s as i have MUCH less knowledge on these and their components....

[tunnels]

I have a 2003, 225 4 stroke that acts like it is starved for fuel at low RPM. I have replaced the fuel line, bulb, water/fuel separator and the filter on the engine. The engine will idle OK until I give it some throttle then it chokes down. The only way to get it up to speed is to have someone pump the fuel bulb and then get it above 3000 rpm ASAP??? What am I missing here?
Gravy

Fuel pump would be the first thing i would be looking at and test the delivery pressure and flow rate . Have never had fuel problems as i always use as bigger fuel lines as possible right up to the last connection on the motor . Big filter water separaters so at max delivery theres little strain on the fuel pump . Do both motors come from separate tanks ? what about kinks and something sitting on the hose and squeezing it partly shut some where . How old are the lines have they ever been replaced ? Fitting can also slice a slither of inside liner of the hose and just part;y block the line . Air leaks in the suction side that dosent show up when you pump the bulb as they sometime close when pressurized !!
Have fun !!

[cb1003k9]

I think I have the opposite problem. I have a 2005 Yamaha 225 4 stroke. Runs fine at idle and low rpm. When I get to 3500 rpm trying to get on plane it starts to bog down and starve itself. Replace plugs, fuel/water separator, added gas treatment, put 50 gallons of fresh gas in and still get same result. Boat has been barely used with only approx. 100 hrs on motor. Any suggestions.

[mitch]

check your fuel pressure with the motor not getting used ,much most likely gum has built up on filters I would be cleaning the vst out and the filter on the bottom of the high pressure fuel pump.

[fisherchow]

I Have The Same Motor, I Had The Same Problem. I Changed The Hoses, Water Seperator. It Was Driving Me Nuts. Had The Gas Tank Cleaned. Finally Had A Mechanic Come Ride With Me. The Motor Would Act Up At The Same Place Every Time, We Ran Back And Forth.
I Knew It Was An Obstruction In The Gas Flow When The Bulb Would Suck Flat. I Disconnecte The Line At The Tank And Pulled It Out. Some One Had Put An Inline Filter In The Line Just Past The Tank Inlet. It Had Rubber Like Stuff In It. Once It Was Removed The Motor Runs Like A Clock.. Wird Stuff Will Drive You Nuts

[351triton]

2005 225 yamaha 4 stroke problems

I have a 2005 Yamaha 225 4 stroke. Runs fine at idle and low rpm. When I get to 3000 rpm trying to get on plane it starts to bog down. Replace plugs, fuel/water separator,clean vst tank. clean injector still does the same and check fuel pressure and it was 40psi which is fine any ideas anyone

[greasyshaft]

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