See full version: 1999 Yamaha 225 smokey at idle and rough at low RPM
I simply asked Yamaha (dealer) Service to "fix it" given the symptoms I presented above. Not sure how much testing was done, but he said there was a service bulletin on the O2 sensor and replaced it. ASSuming, perhaps, that was the cause of my symptoms? Nothing else was done, to my knowledge, that addressed the problem. And it didn't run better, even for a while, after this service. more
Also, he mentioned that rodbolt might recommend not only poking through the mesh. but (gasp) even removing it! I'm waiting to follow my son into the motor since Ed showed him. But again, help and advice is appreciated.
Tried:
Paid local Yamaha tech $400ish to replace the oxygen sensor and "solve the problem" which may have involved other tests. but no substantive work. It now runs as bad as ever; no improvement at all.
Re: 1999 Yamaha 225 smokey at idle and rough at low RPM here
Is this in the Yamaha service manual? I have read about this on other forums, but have not been able to find anything in print regarding this statement. I can't find anything on this in my SELOC and I have practically read half of it! I would be surprised that the default fuel map (without an O2 reading) would run lean enough to risk engine damage. On a car the system resorts back to reading off the MAF, TPS, and IAT. Since this engine is without an MAF, I would think a fail safe design would simply resort to throttle position and air temp.? more
The story is long, but we took care of about every other part before resorting to the O2. I still suspected it bc the engine was running so rich that the engine was guzzling gas, smoked more than what I thought was reasonable, and every plug was soaked! What also sealed the deal was a Yamaha tech that told me he has come across OX66's that had good O2 sensor readings, but still caused the engine to run bad. Replacing the O2 sensor in those cases resolved the running issue after eliminating all other possibilities.
Something else I learned is that TPS is ridiculously sensitive! You can tap that baby with a screw driver after tightening it down and it will affect the signal. Spot on TPS=better running engine!
From what I'm reading here I'm thinking maybe I need to check the Throttle Position Sensor or VST and fuel line for leaks or pressure fluctuations. more
I've done everything else I can think of, like cleaning VST(was very clean), Hight Pressure regulator filter screen (very clean), changing all plugs, water seperator, fuel filters, plug ends resistance check, low pressure fuel pumps replaced. sync & link, O2 sensor cleaning, etc. I did have one of those cheap fuel pressure guages from Harbor Freight on the VST to check the fuel pressure, but it started pissing gas all over. It was at 35 lbs during the test which was at idle. It now is in the garbage. I'm going to call Simyamaha tomorrow and get the test harnesses and fuel pressure guage, as I've never done these things before. Does this make sense? I am not a mechanic, but I try.
Hey Guys,
I am new here and hoping for some imput to my problem. I own a 2002 Yamaha OX66 225.
I have been having a surging issue lately at idle that seemed to resolve itself when the motor warmed up at the house. I Went fishing yesterday and she seemed to run fine on the way out to blue water. While *****ing we would pull up when we had a fish on and she would stall while idling. Seemed to run fine when *****ing. When we ran in we got within a mile of shore and she shut down with a high water temp alarm. Lots of weeds yesterday, so I figured something got sucked into the intake. Anyway, we limped in, but the water P-ing out was not hot (luke warm). Today I began checking things over. I pulled the water temp sensor and two switches on each head and checked them and they were within ranges. I ran the motor up and discovered while using a laser temp sensor on the heads and thermostats that I had a hot cylinder on the starboard bank #1 cylinder (175*). I pulled the thermostat and it looked like there was a lot of crap in there, so I dumped about 4 cups of white vinegar and water in the thermostat housing and let it sit for awhile. While I waited for the vinegar to work, I pulled the O2 sensor thinking that it may have had something to do with the shut down. It was clean. I mean really clean, and the dogbone was completely clear. Ran it up again and the hot cylinder had cleared and was running well at the house,.but still surging. I took her out on the water and tried to run her WOT and got to about 5K for a couple minutes and she shut completely down. No water temp alarm. I tried it again and the same thing happened. I'm at my wits end!!
Is there anybody out there who can shed light on this issue. Am I on the right track?? here
the ECU controls the ground.
the resistor is only in the circuit until about 1100 RPM to reduce pump operating voltage to about 9V.
above about 1100 the resistor is not used. this gives it a two speed pump.
what did you find that caused the no voltage? more
15 volts seems high for a 12 volt battery that is not on a charger here