ox66 surging

[22angler]

Ok, I have a 2001 200hp ox66 saltwater series. It starts right up and idles great. When I bring it up to 2000rpms it begins to surge. It floats between 1700 and 2100. Decarboned, with yam spray, cleaned O2 sensor. Tested O2 sensor. Voltage across blk and grey at idle is between .63 and .59 At 2000rpms it is between .34 and .48 Fuel pressure is dead on 38psi and never changes between idle and 2000, even with a quick throttle. I have not taken it out on the water to see how it does at wot. I don't want to make anything worse. This may be my imagination but it seems to surge worse as the fuel jar drops it's fuel level about a half an inch. If I pump the bulb, it "seems" to run better. Any help would be appreciated

[boats.net]

If pump bulb helps then probably have a fuel restiction in fuel lines, filters or pickup tube in gas tank, or low pressure fuel pump problem.

[jb123]

what happens to the ball when this happens?

if you see the filter half full you may have an airleak there, try reseating

[Bobtmann]

I had a similar problem with my "04 200hp ox66 and it turned out to be a leak at the engine fuel filter. When I checked and cleaned the unit the filter didn't seat properly and the cup was able to screw on but not all the way and it produced a leak. good Luck!

[eddie m]

22, Check my post on the next page (surging). I purchased my rig used and it was poorly serviced but these motors are good runners and very reliable. It runs good but not like I want it. I know this motor can run like a clock. I am still learning and will pass on any information as I diagnose and repair. This site has all the information and diagrams needed. You can get any part and purchasing is easy. My brother and I just purchased a new Yamaha F 250 from this dealer. He has anything you need and is very helpful. Along with the manual you can repair anything on ox66 motor. Good luck.

[22angler]

surging

I have checked and rechecked the fuel filter jar. I believe it is ok. What about the lp fuel pumps? They don't appear to be leaking, but I'm not sure if I could see it if it was. I'm going to go back to the basics and check spark and fuel.

[eddie m]

There is a vacuum test used on the low pressure pumps to check the seal. Draw a vacuum on he inlet side of the pump while holding your finger over the discharge. It should hold the vacuum. You cannot tell from a visual if they are comprimised. I used a mini vac and both mine failed, of course. It is easied if the VST tank is unbolted to make room. I did replace them but the surging continued. I motor was not serviced adequately to my standards but I purchased the rig for the boat and knew the reputation of the SWS. I did R&R the high pressure fuel lines, cleaned all grounds and connections. I did find a broken connector on my #1 coil lead to the CDI. It was barely making connection. 4 out of 6 plug boots failed Ohm. specification. I am getting close to fixing. Mine has a few contributing issues. Have you serviced the motor prior to the problem starting? Get the shop manual and start with the simplest trouble shoot. Compression, spark tester and fuel flow. Good luck.

[jb123]

to test LP pumps, unbolt, pump ball, if gas comes out of vac port, replace. new gaskets will be needed