1999 200vmax OX66 idle / engine dies problem

[hvtexskeeter]

My 99 OX66 200vmax efi does not want to idle very long when in gear. It seems to do ok sometimes but after extended idling (over 1 minute sometimes less) it sneezes and dies. It is also very difficult to load it onto the trailer after idling around boat dock. It seems to load up I guess. I read a post on here and did the following:
1. Replaced all 3 LP fuel pumps (old ones were 3 years old and leaked when I pumped the primer bulb) and used new gaskets.
2. Drained all fuel out of both 25 gallon tanks in boat with electric fuel pump setup I borrowed from my friend. To hopefully eliminate any water in the fuel tanks as I have never done this.
3. Changed small fuel filter at motor and oring above filter.
4. Changed inline yamaha fuel/water seperator cartridge.
5. Checked adjustment / syncronization of oil pump lever, checked good.
6. Checked adjustment syncronization of throttle valves, checked good.
7. Fueled up with fresh premium unleaded gas. I usually use reg. unleaded but figured I would try premium due to all the ethanol in reg unleaded.

Went to the lake to try it out and it still does not like to idle in gear. Motor dies and sometimes sneezes. Really no worse or no better than performing the above items. What next? Replace the 02 sensor or take it to the shop? The motor runs great at all other speeds up to WOT with no problems. Unfortunately I must Idle out of the no wake zones around here to avoid a ticket!! Thanks in advance, HVTexSkeeter

[hooken203]

WOW you did most of what I would have said to try. I didnt see spark plugs on your list. Also plug wire end cap can be a problem. Look at your plugs where the wire hooks up if they look black or if you can see the metal is eroded then replace caps. Plugs could also be fouled due to leaking fuel pumps

[hvtexskeeter]

I forgot to metion I did replace the plugs also. I am going to look at replacing my battery which I think is a couple of years old, then look at testing the throttle position sensor as metioned in another post. Anyone else have any ideas? I looked at my yamaha maintenance manual and it said reed valves. I hope its not reed valves, may be time to take it to the dealer and pay them the big bucks to diagnose it.

[big_b16]

Dude...hold off on the dealer. I've got mine there for that exact same problem. I'll let you know what his diagnosis is. I've taken it to a Yamaha Master Tech with the hope he can properly diagnose it the first time and not waste my money or his time. I'm not to familiar with the operation of reed valves...but if the engine was able to reach WOT rpms, would the reed valves not be alright?

[hvtexskeeter]

Thanks big b16 I will probably wait and see what else I can figure out. I think the reed valves are ok as it does not run as bad as a black motor I had that the reed valves were broken on. I am going to check out my battery and see what I can do to check the throttle position sensor. Took it out on Lewisville lake yesterday and it still was not idling good. I cleaned the battery connections with no help. Had a heck of a time getting it back on the trailer after I idled around near boat dock. I think it died 4 times in the no wake zone by boat dock. When trying to get it on trailer it seemed to load up when I tried to power it up onto the trailer. Keep me posted on what the dealer says. Thanks all for the help, HVTEXSKEETER.

[hvtexskeeter]

Ok Sunday I did a little troubleshooting:
1. Removed main battery a 5 year old Optima and battery voltage was 12.10 after I charged it 1 day ago. Oh well its 5 years old, replaced it with a new Optima blue top marine starting after top charging it. New battery voltage is 13.4. Ran motor in driveway with earmuffs and battery was no help. motor will not idle very long in gear or in neutral still.

2. Performed 02 sensor clean and check per Yamaha maintenance manual and article from bass and walleye boats. when you heat up sensor it does change voltages when heated with propane torch. The only thing that didnt match the yamaha manual was heater resistance. it was not 100 ohms as specified. It was around 5 ohms and didnt change when I heated it. It did heat up when connected to a battery, but did not get very warm and took 30 seconds to notice any change in temp. Performed Super Sniffer Tests from bass and walleye article and voltages read between .3 and .6 volts and never went near .9 volts. I could not take boat to the lake due to it was idling so poorly I did not want to take a chance so I could not perform Greg Hinds tests of the sensor at the lake.

3. Changed plugs again just for the heck of to see if it would help, no help NGK BR8HS10 plugs as reccommended by sticker on lower cowling. No help, and also checked spark with spark plug tester and spark seemed good.

4. Checked knocking sensor, seem to check ok with very small ac voltage output when tapped on checks good.

5. Measured High pressure fuel pump resistor resistance, checked at .5 ohms with my fluke 87. It checked at .8 ohms with my cheap meter then checked it with fluke today and its at .5 ohms, checks good.

6. Measured throttle posistion senor output voltage, was .630 volts with throttle linkage connected and went to around 5 volts a WOT. checked it also with throttle linkage disconnected was at .5 volts exactly. Checks Good.

I guess I need to buy a Diagnostic Test indicator P/N 90890-06765 and that should show me any codes that I have. I just want to go to the lake and go fishing but I guess I will have to stay at home and keep trouble shooting.

The BOSCH 02 sensor p/n 15727 that was talked about in an earlier post would not fit into my 02 sensor housing. It did only cost 55.00 at Oriely autoparts and they did take it back and gave me a refund. Will the NGK 02 sensor for sure fit into the 02 housing on a 99 0x66 200? if so I will buy one off the internet as no autoparts stores in the DFW area have one that I can find. Thanks all for the help, HVTEXSKEETER.

[hvtexskeeter]

Ok could not stand it and started troubleshooting again tonight after work.

1. Inspected Atmosheric Pressure sensor. output voltage was 3.9 volts within limits checks ok.

2. Inspected Intake Air temperature sensor. Read 1.9 volts at 93 degrees on a nice cool July afternoon in Texas. Book said 3.4 to 5.3 volts at 68 degrees F. so I will have to guess and say this is ok at 93 degrees.

3. Purchased a generic fuel injection test gauge kit and Measured the fuel pressure from the High pressure fuel pump. Pressure read 28-30 psi after running engine for 1 minute which was difficult because it didnt want to run that long. The pressure was a little low but I replaced the high pressure fuel pump 1.5 years ago ($700 dollars) so I hope it is ok.

4. Removed High pressure fuel pump / vapor separator assembly, removed fuel pressure regulator and inspected small filter screen behind regulator, looked good. Inspected High pressure fuel pump filter on bottom of pump and it looked perfect. Reinstalled all of the above.

5. Inspected fuel pressure regulator operation with Mity Vac. Fuel pressure dropped when I applied vaccume on fuel pressure regulator so It checks good.

6. checked cylinder compression. All cylinders were between 95-100 psi and this is the way this engine was when purchased 6 years ago. Ran great then and ran great up untill about 1 month ago.

I have had very good luck out of this motor and have owned it for 6 years and use it on the average of 2 times a week all year long, yes even the winter. I probably use it less during the summer than all other seasons. The motor still runs ok even with this problem and I could probably go to the lake and use it but dont want to burn it up and its is a pain idiling around the no wake zones here. I just want to fix it before the fall fishing season starts.

If nothing else I have learned where almost everything is located and what it does on this motor. But the motor still has a rough idle and stalls after 30 seconds if that long. I can keep it running by revving the throttle a little but acts like it wants to load up and seems to be running rich.

[big_b16]

Hoping to hear from the tech Tuesday. I'll be sure to let you know if he finds anything. Looking at your numbers (which may be different due to engine) but I thought the high pressure had to be 35psi at all times. At least it does on mine (2002 OX-66). Good luck...be sure to let us know if you find the problem. My boat is sold and I don't want to spend more money than I'm making off of it.

[201pro]

Does pumping the bulb help anything when it is idleing bad?..Mine did what yours is doing from a sticky check ball in the primer bulb..

[sarmst100]

Man, you've done alot so far. Forgive me if I missed something.

Did you check the O2 sensor with it idling at operating temperature instead of the bench test? From what I understand the flame bench test should not be used. It is obsolete now.

Also, did you set the idle at operating temperature? Mine idles high at first and then comes down as it heats up.

I had a bad ignition coil on mine not too long ago that would cause it to surge at high speeds. It was on one of the cylinders (#3 I think) that is not used at lower RPM's so it didn't effect the idle. Yours could be on one of the others so check the resistance per the service manual.

[hvtexskeeter]

Yeah I put a new primer bulb on it a couple weeks ago and it did not seem to help. I have not tried pumping it while the engine is running but I may try that next time I try to trouble shoot. I will try testing the ignition coils but I think I will have to have some peak voltage tester that is called for in yamaha manual to do that test. I willl look into it and test the ignition coils if I can. Thanks all for the help, any other advice? Gasoline and a Match? I am still wondering about the 02 sensor. Has anybody tested the heater resistance on there 02 sensor? like stated before It was alot lower than the book said it should be.

[hvtexskeeter]

Ok I have another plan. I am going to remove the fuel injectors and send them to Hydrotech and have them cleaned and flow tested as I know this has never been done on this engine. When doing this that will give me a chance to dig in deeper and look at the reed valves. I hope that all this is not another huge waste of time but I think cleaning the injectors might be a good thing even if it does not fix the idling problem.

[big_b16]

All the primer bulb does is bypass the lift pumps...as long as you have good fuel pressure at the high pressure port and you can supply the maximum fuel at WOT...that isn't whats causing the problem.
Spoke with the mech today. He hasn't started on it yet but we went over what he plans on doing. Main symptoms again are fouled plugs and stumble/stall at idle. I think the latter is caused by the former. First he's going to check for codes with the winky/blinky when the problem is occuring. Then he's going to do a link and sync (thinks .030" on the oil pump linkage is too much) and he noted that the idle stop screw is not seated when the throttle plates are all the way closed. During the link and sync, he'll verify proper TPS operation. He's also going to make sure the stator is putting out the correct voltage at idle. I couldn't test the latter w/o a DVA. Another thing he said could cause it to run rich is if the thermistors aren't putting out the right signals. I know the thermostats are good, but the thermo switch assemblies have not been checked. If they're giving bad signals...the ECU may not know the engine has warmed up.

I'll let you know what he finds out...looks like we've been down the same path. Of course, I contemplated sending the injectors out but with pristine screens, I figured they were good. If they were clogged or partially clogged, you'd worry about running a piston lean and destroying the piston. Looking at my plugs...I've got no issue concerning a piston running lean...mine are drowning in oil.

[ghind]

I hadn't read the middle posts

3. Purchased a generic fuel injection test gauge kit and Measured the fuel pressure from the High pressure fuel pump. Pressure read 28-30 psi after running engine for 1 minute which was difficult because it didnt want to run that long. The pressure was a little low but I replaced the high pressure fuel pump 1.5 years ago ($700 dollars) so I hope it is ok.

When you turn the key to the on position, before your start the motor, the pump should quickly get you to 35psi.

It should be there within seconds and should stay there the whole time your engine is running.

Maybe your gauge is a bit cheap. Tell us more. What PSI does it read when

1. Engine off for at least 10 minutes then bump key to ON (not start) position for 10 seconds
2. What does it read 1 minute after switching off
3. What does it read with engine running after a few seconds and a few minutes?

Checking the plug caps is easy and worth doing because it is easy. i doubt that is your problem, but worth checking. Unscrew them off the end of the plug lead (the cap just unscrews off the lead!). What resistance do you measure each to be?

i doubt there is much harm starting the engine at the ramp, stay on the trailer. Warm it up and watch the o2 sensor readings. Just see what they are up to 1500rpm. you may be able to do 1500rpm in gear on the trailer to warm it up and test, depending on your boat and trailer.

The oil rod being out 30 thou will not cause the quick fouling problems you are having. Still worth fixing but that isn't it.


2.

[ghind]

Is your idle speed 730rpm +/- 25rpm?

[sarmst100]

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by hvtexskeeter &raquo;</TD></TR><TR><TD CLASS="quote">Yeah I put a new primer bulb on it a couple weeks ago and it did not seem to help. I have not tried pumping it while the engine is running but I may try that next time I try to trouble shoot. I will try testing the ignition coils but I think I will have to have some peak voltage tester that is called for in yamaha manual to do that test. I willl look into it and test the ignition coils if I can. Thanks all for the help, any other advice? Gasoline and a Match? I am still wondering about the 02 sensor. Has anybody tested the heater resistance on there 02 sensor? like stated before It was alot lower than the book said it should be.</TD></TR></TABLE>

To check the ignition coils, use a multimeter and check the primary and secondary resistance per the service manual. This is probably not your problem but it's easy to check just to make sure.

[hvtexskeeter]

when you turn the key on it the high pressure fuel pump immediately goes to 29 psi. After you turn the ignition switch off the fuel pressure drops to less that 10psi within 10 seconds. With the engine running the fuel pressure remains around 29 psi and stays there when engine has been running for a couple of minutes. It is difficult to keep the engine running this long. I tried to take it to the boat ramp and try the 02 sensor test but the engine will not run in gear for long and when you try to increase the throttle it dies.

[big_b16]

Is the spec for your motor 29psi? I'd ask Rodbolt on iboats, he should know for sure what your high pressure should be. The only value I can recall seeing is 35psi. But you say you can get WOT, so maybe you're alright. Mine is at 35psi when I energize the pump.

[ghind]

Do you have the service manual?

What is the model number of your engine? Is it a 3.1 litre engine? I don't have the manual for the standard 200, only the vmax 200 ox66. The Vmax 200 is rated to use more fuel than the standard 225 and it isn't just wasted. i.e. the vmax 200 is stronger than it says. So if you have a stock 200, it may be different to my numebrs.

My service manual, in section 3, inspection and adjustment says that the fuel rail pressure should be 35.6psi.

If your motor should be the same, 29psi would cause all sorts of problems including stalling. In section 4 in my manual, there are tests for the fuel pressure regulator. Sounds like your pump is fine.

Also, can anybody tell us what fuel pressure their engine holds 10 seconds after turning the key off. Down to 10psi in 10 seconds seems low like it is leaking pressure off via the injectors or something but I am really not sure. I don't run a Yammie any more so I can't test it for you. I half think I may have had 10psi after 10 seconds myself but it sounds wrong so we need somebody with a happy engine to check.

The manual is wrong for the o2 sensor heater resistance. It is not 100 ohms. That would equate to a 1.4 watt heater! Wouldn't heat anything!! I was thrown off by this too.

What happens to the fuel pressure when you try to keep the engine running on the ramp? What is the fuel pressure doing when the engine dies?

PM me your email address???

[hvtexskeeter]

In my spare time tonight after work I removed the fuel rail and fuel injectors. They looked brand new and removed the tiny inlet screeens and cleaned them. they also looked perfect with no debris on them before cleaning. I dont know if I am going to spend the money on having the injectors flow checked after looking at them. When I had the injectors and fuel rail removed I removed the reed valve case and reed valve assemblies and set them on my bench and inspected them. The reed valves looked perfect with no curl or chips/cracks. I reinstalled everything and am going to get a good 0-50 psi calibrated gauge from work tommorow and try measuring the high pressure fuel pump pressure again. I just dont trust the taiwan gauge that I purchased at oriely auto parts. Before I shell out $600+ on yet another high pressure fuel pump I want to test it once more with a known good gauge. Has anyone else been eating up high pressure fuel pumps on their Yamaha's? When I purchased the boat used it had a new pump put on it then (by previous owner before I bought it) and then again a couple years ago. I am running a yamaha 10 micron fuel water stainer and always change the engine mounted filter at least once a year. I ordered the diagnostic test harness / light and it should be here next week