Yamaha 2002 Vmax 200 OX66 won't idle

[fishinberg]

I have a 2002 Yamaha Vmax 200 OX66 EFI with a couple hiccups. First off I have checked and have good compression and spark.

Problem 1:
I had an intermittent issue with the VST pump not turning on when I turn the ignition on. This happened twice to me last week, both times right after my buddy hooked up to tow me it fired. Since then I've run it without a problem for 5 days straight with no issue. I put my multimeter in the boat to check voltages the next time it happens.

Problem 2:
My engine seems to idle really rough and cough and sputter when I'm idling. Sometimes to the point it dies. I think it's fuel or fuel system related as I've heard nothing good about the ethanol. Last fall I replaced all the low pressure pumps and installed a new main fuel filter (boat side), but this spring it won't idle good at all.

Could you give me a list of things to check/clean and possibly how to do it. I don't own the service manual, but might look at purchasing one if they aren't too spendy and you know where to get one.

 

[cousinabe]

Re: Yamaha 2002 Vmax 200 OX66 won't idle

check your injection unit relay and resistor are in spec.

http://forums.iboats.com/showthread.php?t=310079&highlight=ox66+relay

you should really get a genuine service manual for that motor. It's a GREAT investment if you want to work on it.

Also you can clean the pressure regulator screen.
take it a step further and clean the fuel injector screens.

You don't want to run the motor when it's sneezing like that. it's sick. the lean condition can blow a piston. the efi motor should start right up, idle at 1100-1200 cold and settle down to 750-800 when warmed. no sneezing, no stalling.

 

[fishinberg]

Re: Yamaha 2002 Vmax 200 OX66 won't idle

Can you suggest what the best manual would be for reference? I've found that there are several out there (Yamaha, Seloc, Clymer) from your experience which contains the most detailed and user friendly information?

 

[fishinberg]

Re: Yamaha 2002 Vmax 200 OX66 won't idle

I forgot to mention that while it coughs and sputters at idle it seems to run fine at higher rpms. If it was starved for fuel at idle wouldn't that issue be magnified at higher rpms? Just trying to get the old Yami nursed back to health!

 

[TimC2520]

Re: Yamaha 2002 Vmax 200 OX66 won't idle

I had a similar situation on mine a couple of years ago.
I made sure ALL of the required preventative maintenance was done, then I ran a "dunk de-carb" and I'll be darned if that didn't cure my problem.
Not saying that is the problem, but sometimes, it's the simplest things.
Now I run SeaFoam through her every 50 hours.

Check your TPS, plugs, plug caps, O2 sensor, lp pumps, VST filter, make sure all of these maintenance items have been done.

 

[fishinberg]

Re: Yamaha 2002 Vmax 200 OX66 won't idle

Ok, finally got time to look thru it.

Cleaned VST screen, pressure regulator screen, injector screens.

Performed Link and Sync as well as set TPS per service manual. Idle screw 3 turns open ~ .62volts or .498 volts with valves closed.

Removed O2 sensor and the tube was full of gunk and carboned up. I cleaned it all out and soaked the O2 sensor in ring free. It seemed to run better for a few days, but now is acting as bad as ever.

Motor idles erratically. Starts at higher idle and then will surge - rpms drop and raise and then kills.

I keep going back to the O2 sensor. Voltage at idle seems high ~.68-.74 and doesn't seem to drop to the .3-.6 range I read it should be.

The 3 lift pumps were replaced last fall, but is it possible they are bad again?

I'm reaching my expertise level and getting very frustrated. Think I might order a new O2 sensor and pray!

Please help!!

 

[rodbolt]

Re: Yamaha 2002 Vmax 200 OX66 won't idle

go back to the basics,test spark,test compression fix the fuel system.
the O2 sensor test isnt really valid until the engine has run about 10 minutes and the gearcase is submerged.
then a reading like yours indicates a very rich mixture,could be a faulty CTS,a bad lift pump,a leaking injector,a clogged pressure regulator filter, or possibly an ign issue.
a leaking needle in the vst will cause engine flooding as well as a leaking injector.
none hard to find you just need a fuel rail pressure gauge.

 

[fishinberg]

Re: Yamaha 2002 Vmax 200 OX66 won't idle

I picked up a cheap fuel pressure test kit. Fuel rail pressure seems to hold at ~35 PSI while the motor is running. Doesn't appear to fluctuate at all even while motor is surging pressure holds steady. Remains pressurized after motor is shut off too until I loosen pressure gage to remove.

Monitored voltage of elect fuel pump and it stays ~ 10 volts at idle and when motor surges dips to 9.5 v, but pressure doesn't change. Sound ok?

I will remove the VST again tonight and double check the pressure regulator filter and fuel pump filter and needle. What should I look for on the needle?

I'm going to see if I can find a couple lp pumps locally to replace. Replaced all 3 last Sept and again one of those when I was in Texas a month ago that was visibly leaking. Is it possible that I have another bad one?

What is the CTS and how would I check for that?

Are there any other sensors/voltages I could monitor tonight while running?

Thanks for the help.

 

[saltair]

Re: Yamaha 2002 Vmax 200 OX66 won't idle

Does anyone know if this problem was resolved?

Having similar problem with 225 ox66.

 

[saltair]

Re: Yamaha 2002 Vmax 200 OX66 won't idle

Nevermind, I found that 2 of the new mallory low pressure fuel pumps were leaking. Ordered new yamaha pumps to replace them. The diaphragm in the mallory is not the same as in the yamaha. They might have been fine, but I did the seafoam decarb, and rain kept me from running it out right away. Ended up sitting in the system for about 48 hours. I think this could have softened the rubber. The diaphragm in the yamaha, however, isn't rubber. It is a clear hard plastic, like thick cellophane.

The middle pump had a rip in the diaphragm. The top pump was leaking from the bottom of the gasket on the front. The rubber gasket was falling apart around the bolts that hold it on the motor.

I hope the sea foam didn't soften anything else. Only running issue is stalling and rough idle, probably from fuel going into the block from the middle pump.

I mixed and matched parts from the yamaha and mallory pumps to see if it solves the problem until new pumps come in.

If I don't post anything else, it solved the problem.

 

[rodbolt]

Re: Yamaha 2002 Vmax 200 OX66 won't idle

the replacenent 6e5-24410-30 pumps have rubber diaphrams.
one lean sneeze on ethier style can pop a diaphram especially on the 3.1L motors.
did you recheck the O2 sensor output voltage? excessive fuel can clog it again.

 

[saltair]

Re: Yamaha 2002 Vmax 200 OX66 won't idle

Rodbolt, if those had the plastic diaphragms, were they original from 2000?

would you recommend sticking with yamaha brand for the replacements?

Also, do you think I screwed anything else up, other than the o2 sensor?

It seems to idle fine and starts right up on the hose, with the pieced together pumps. I don't plan to run it like that after seeing the softened rubber gaskets.

I am going to order the test harness for the o2 unless you can tell me how to test without it. I pulled the o2 while trying to solve the idle issue. the draw tube was oily, but it hadn't reached the sensor. Will clean the tube again when I put the new pumps on.

 

[rodbolt]

Re: Yamaha 2002 Vmax 200 OX66 won't idle

ube aint so much an issue, the sensor is.
however its dirt simple to test ith some jumper leads wit alligator clips from radio shack.
slip some small paper clips up the leads at the o2 sensor output,gray sleeve not blue.
then attach the meter to the papaer clips.
read the running gearcase submerged output voltage per about 3 tech bullitens.
if output is ok no need to do anything.

 

[saltair]

Re: Yamaha 2002 Vmax 200 OX66 won't idle

Thanks, Rodbolt.

That is 20 bucks I'll put towards a better voltage meter.

I'll test it as soon as the new pumps are on.

 

[fishinberg]

Re: Yamaha 2002 Vmax 200 OX66 won't idle

I ended up dropping my boat off at the only good Yami wrench I know in the Mpls area and $100 in labor later it runs better than it has in 5 yrs. Guess there are some tricks a manual won't teach you. Thanks for all the help

 

[nickmo]

Re: Yamaha 2002 Vmax 200 OX66 won't idle

Well, don't leave us hanging. What was the problem?

 

[fishinberg]

Re: Yamaha 2002 Vmax 200 OX66 won't idle

Basically he just did the same thing I thought I had done. He went through and did a general tune up. No parts or anything, which I was rather happy with. I've since switched to running only non-oxy gas in it and that seems to also help keep it running smooth.

 

[Bitsamonkey]

Re: Yamaha 2002 Vmax 200 OX66 won't idle

Hey Saltair, throw those Mallory pumps in the garbage. Those parts have no business on a boat! I unknowingly ordered two of them for my V6 Yamaha and had both fail in short order. The first one tore the diaphram because the little stainless cup that sits on top of the spring has razor sharp edges from the **** poor stamping. The second (I caught it in time and filed down the edges) started leaking from the body because of a rubber gasket that won't hold up to gas. After taking the second one off I also realized it was leaking past the valves internally. Total junk!

 

[rangerfishn]

Re: Yamaha 2002 Vmax 200 OX66 won't idle

fishinberg,

I am looking for a good Yamaha mechanic in the Mpls area. I'm experiencing the no idle feature provided by Yamaha. I don't have he work area nor the tools. Can you give out the name or email it to me?

rangerfishn.