Yamaha 225 VMAX ox66 shutting off while on plane

[MeanGreenPathfinder22v]

Ok, here's the scoop. I just bought my uncles 2200v Pathfinder powered with a 2001 225hp Yamaha VMAX ox66 3.1L engine. He told me that while on plane the motor will shut down after a short while. Then when he would start it back up, it would only allow him to idle unless he kept the motor off until it cooled down then after plane it would do the same thing. He told me it was the oxygen sensor that went bad. He opened the cowling before to show me and he had the O2 sensor completely "ghetto" rigged. He said that he lost one of the parts to it and instead just put an old spark plug where the part was so it restricted the air flow??? Leave it to my uncle to do it this way why am i not surprised. I just need to know if he was correct in blaming the O2 sensor or was it something else that couldve caused the problem? What else should i clean/replace so the engine is running like new. Also if anyone could provide the part number for the O2 sensor and where the cheapest place i could purchase it. Thanks so much in advance.

[Rich Z]

Clean fuel filter in vst and check diaphragms on low pressure fuel pumps for leaks. You can gat all your part numbers and parts from boats.net

[MeanGreenPathfinder22v]

i checked out boats.net and it didnt have an O2 sensor listed, is listed under something else? sorry im new to dealing with boat motors. thanks!

[JUST-IN-TIME]

what year motor??

[MeanGreenPathfinder22v]

2001, model #vx225tlrz

[slapshot]

Definately get the O2 sensor repaired or replaced depending on how bad the hack job repair is. That O2 sensor is critical on the OX's to run properly. Once you take the sensor out once, you'll see how easy it is.

I'd also check the VST filter also. See the sticky on top of this forum for a guide. The problem you describe is typical of a clogged up VST filter. The motor sucks up the gunk in the VST tank and starves the motor for fuel and it stalls. After being off and the suction in the fuel system goes away, the gunk falls off the VST filter screen back to the bottom of the tank, just to be sucked up again.

If that doesn't fix it, then I'd move onto the fuel pumps/diaphrams also.

[Rich Z]

65L-8592A-01-00 SENSOR $305.99 $238.65 From boats.net

[MeanGreenPathfinder22v]

wow, you guys are awesome! thanks so much, im going to try and tackle everything thursday and ill let everyone know how it pans out

[MeanGreenPathfinder22v]

by the way, where is this "sticky" that i cant find info on the vst cleaning?

[slapshot]

Ask and ye shall recieve....complete with photos.

http://www.bbcboards.net/zerothread?id=66928

In case you haven't discovered the official forum for Hewes/Maverick/Pathfinder/Cobia boats, it's here and a great source of info.

http://www.mbcboats.com/fusionbb/index.php?

[MeanGreenPathfinder22v]

Man, thanks alot i appreciate it! I didnt even see that forum< illl have to check it out!

[slapshot]

Anytime...welcome to the Yamaha/PF club

[MeanGreenPathfinder22v]

i was doing a search on the forums for the oxygen sensor replacement and came across one from "dalehollar" from 06/29/08 and he posted about a bosch O2 sensor from advanced auto. I picked up the part today to check it out and it looks like it may work. I was wondering if anyone had a picture of what a correct oxygen sensor assembly on the motor looks like, remember mine currently is ghetto rigged with a spark plug. thanks!

[DaleHollar]

Im sent with phone number. Call me and i'll walk you through it.

Donald

[MeanGreenPathfinder22v]

Thanks to dalehollar, ive successfully installed my replacement O2 sensor, due to tropical storm fay, i will have to wait to put her in the water and test her out. Ill keep yall posted!

[DaleHollar]

Have you had it out yet?

Donald

[MeanGreenPathfinder22v]

No sir, taking her out tomorrow actually. Weather finally looks good here. I'll let ya know how she runs.... Thanks again for all of your help

[MeanGreenPathfinder22v]

Well, took her out today, and i assume that the O2 sensor wasnt the only problem with the motor. I launched her this morning, cranked right up first time, and let her warm up while i waited for my buddies to park the trailer. Started idling out from the ramp for about 10 min. When i finally got out of the no wake zone, i went to take off and it bogged down completely, wouldnt even attempt to plane off. I tried taking off a half dozen more times and same thing happened until motor completely shut off. I then tried to return to the ramp at just idle, and it would cut off during idle as well. After dozens of restarts, my boat sounded an alarm, not sure if it was overheating alarm or something else? I had to keep starting, putt for a min or two idling and then shut her down every few minutes. I felt the primer bulb during all of this and it wasnt firm what so ever, i kept squeezing and didnt get tight at all.. Is the bulb supposed to get solid with fuel? I could feel alittle gas in there but it didnt seem full..... What do i check now?

[slapshot]

My next bid would be on the fuel pumps. I'd be looking for either a bad pump(s) or leaking diaphram. They are relatively easy to replace. I believe there is a sticky up there on how to change them also.

[MeanGreenPathfinder22v]

u da man! thanks..... But, what do these LP pumps look like and where are they located? I havent checked the vst yet also.... shoud i do that as well?


Modified by MeanGreenPathfinder22v at 4:50 PM 8/30/2008