yamaha 225 OX66 dies at high speed

[gomezpet]

Have Twin Yamaha 225 OX 66 EFI, 2000.<br /><br />At slow speed (Idle) they both run ok.<br /><br />When getting on plane one engine chokes, surges sputters, dies.<br /><br />Cleaned all filters (twice), isolated to an external fuel tank with new gas.<br /><br />Still same problem. Engine runs for less than a minute on plane then dies.<br /><br />The other engine runs like a champ!<br /><br />Help, any ideas?

 

[foxden]

Re: yamaha 225 OX66 dies at high speed

I would suspect the fuel pump, but others with more experience with this specific engine may help. A primer bulb can also cause a problem with fuel starvation.

 

[rodboltVE]

Re: yamaha 225 OX66 dies at high speed

hello<br /> this is rodbolt from caracas venezuela.<br /> did you check the filter for the high pressure pump in the VST and did you test the fuel pumps. <br /> if you see an excess amount of fuel on the water at idle odds are one pump is bad.<br /> I will try more later as this spanish keyboard is killing me.

 

[gomezpet]

Re: yamaha 225 OX66 dies at high speed

thanks. Will check both the bulb and the fuel pumps today. Reading all the threads on this the most likely culprit is one of the fuel pumps.<br /><br />I did clean the filter in the bottom of the VST, moister sep and inline filters. While checking the fuel pumps today I will also check the pressure reg. I hear it also has a micro screen.<br /><br />Are there any other filters?<br /><br />I pulled the plugs and they look a little wet.(all of them). But again it runs ok at idle.

 

[Spindrifter]

Re: yamaha 225 OX66 dies at high speed

How easy is it to restart after dying? Does it drag like the battery is low or fire right up? My Mercury was doing the same thing, and I chased through the whole fuel system only to discover that the motor was trying to seize! Result 3 broken pistons and it was still running fine except at full throttle it would die.It was hard starting though.

 

[rodboltVE]

Re: yamaha 225 OX66 dies at high speed

hello<br /> leave the presure regultor alone. it has no filter and is rather non servicable. it sounds like a fuel starve problem. and unlike crbs it will run fine until fuel rail presure drops. the cut off may be quite sudden not a gradual bog. it will run fin or almot fine with one bad low presure pump at all but high speeds above about 4K. I reccomend replcing the pumps as maint every 3 years at a minimum.

 

[Yellow Ranger]

Re: yamaha 225 OX66 dies at high speed

First of all I want to mention how handy this site is for troubleshooting, it is awesome, I had this same problem with an 2003 200 V-max, it would run at idle and plane fine then after a 3/4 mile or so it would die and if you would pull the throttle back it wouldn't stall completely, once it sat for a few minutes you could plabne again witht he same end result it would stall, previous to this issue I was having real similar issues and changed the water/fuel seperator, dumped the clear plastic fuel bowl on engine, changed the plugs, water pump etc, finally I started questioning how the clear fuel bowl on engine seated and realized it was leaking a small amount of gas down the outside, I didnt have it seated properly and the fuel system when requesting large amounts of fuel at WOT would starve ...causing it to stall..going to run it again this afternoon although I am real sure this was the issue,.......original issue was moisture in the VSP tank, then an improperly seated fuel bowl was result and second issue after draining VSP....Seafoam here I come

 

[Yellow Ranger]

Re: yamaha 225 OX66 dies at high speed

Ok I went for a test ride after the cear bowl being loose and still dies at WOT, I got with soem local guys who own similiar engines and they recommended taking all 3 fuel pumps off and pumping the primer bulb, I was told if any of the pumps leaked fuel out they are NO GOOD, the bottom 2 of the 3 pumps leaked profusely, I have 3 new pumps that will be here tomorrow, I will install them tomorrow night and run it, so I am crossing my fingers...

Curtis

 

[sgstrick]

Re: yamaha 225 OX66 dies at high speed

Ok I went for a test ride after the cear bowl being loose and still dies at WOT, I got with soem local guys who own similiar engines and they recommended taking all 3 fuel pumps off and pumping the primer bulb, I was told if any of the pumps leaked fuel out they are NO GOOD, the bottom 2 of the 3 pumps leaked profusely, I have 3 new pumps that will be here tomorrow, I will install them tomorrow night and run it, so I am crossing my fingers...

Curtis

where are you ordering your parts from?