'03 Yamaha 200 VMAX stalling

[kmswiber]

Rodbolt17 of course the technician intends on doing testing. I appreciate your help, you don't know how much I do. But I think the technician has his reasons.

I apologize on the model. It is a vx200TLRB. This morning we are going to test ride before he does anything. The hub was pressed in Saturday and I haven't used it yet (used another 25-m). Do you still think I should put some marks on it before going to see if it slips?

[kmswiber]

OK...before dropping off the boat the tech and I ran it. A little after we get over 4500 RPM it lost propulsion again. I made sure I kept the same pressure on the hotfoot and the RPM's still dropped. I don't think the prop is ventilating.

They're changing out the VST Filter and cleaning the O2 Sensor now. They will be done a little after lunch. I'll Keep everyone updated.

Thanks again for giving me your time.

[kmswiber]

They swapped the VST Filter. Cleaned the O2 Sensor, but it didn't test in the parameters Yamaha gives. Should OHM out at 1.0. It OHM'd at .6.

They had to order the part, should (hopefully) be in before the weekend. I'll let you guys know what happens.

Please keep me in your prayers! Have a great day!

[ausnoelm]

I think your terminology is confusing everyone, you say it "loses propulsion" that indicates the motor is reving high, but going nowhere, but after reading things again, I think you mean the motor dies, not loses propulsion!

[kmswiber]

I think your terminology is confusing everyone, you say it "loses propulsion" that indicates the motor is reving high, but going nowhere, but after reading things again, I think you mean the motor dies, not loses propulsion!

What do you mean by "reving"? That's not a word. Do you mean "revving"?

Motor does not die. RPM's steadily decline. While this happens the motor does not push the boat forward.

[kmswiber]

My mechanic replaced the O2 Sensor and VST Filter, and I'm still having issues.

Anyone's input would be greatly appreciated!

[greasyshaft]

Does fuel pressure decrease when you have this problem?

You need to monitor things when having the problem in order to get anywhere.

[kmswiber]

I'm waiting to get more information from the technician. I am obviously not strong in motors and the diagnosing of them. I will have more information Monday evening and I'll update the board at that time. Thanks...

[kmswiber]

Does fuel pressure decrease when you have this problem?

You need to monitor things when having the problem in order to get anywhere.

I found this online. Is this true? If so I can test tomorrow. I appreciate your help and patience:

"Hello I have been told that the way to test a fuel pump on a 99 Yamaha 150 is take it loose from the block put your finger over the hole on the back and pump the primer bulb if gas comes out the hole its bad... "

[rodbolt17]

you simply CANNOT test the O2 sensor output with an ohm meter.
please find a REAL tech BEFORE you burn a piston.

your describing a classic loss of fuel rail pressure.
wether it is an air leak in the suction side, a fuel restriction on the suction side, a bad lift pump/pumps or a failing high pressure pump ONLY careful monitoring of the fuel system will tell.

but at least now you most likely own a good used O2 sensor.