Excessive smoke at start up

[Strat_Yamaha250]

I have a 2002 Yamaha V-Max 250 OX 66 Fuel injection and it smokes a lot every time it's started up. It doesn't smoke like this while running or while idling around just when it is started up. I have been told by several people that it's normal for this engine and I shouldn't worry about it. But it hasn't always done this. Any suggestions on what I should do or what to look for? I am at wits end with it and want to get it fixed if possible.

[99yam40]

If you store the motor all the way down, try tilting it up a little so that the oil will not leak by rings and pool on top of pistons

[Strat_Yamaha250]

I don't have that luxury. Boat stays in the garage and it will not fit unless the motor is all the way down.

[rodbolt17]

its not oil pooling past the rings, thats only a 4 stroke issue.
double check the oil control linkage for correct adjustment.
next time you park it carefully mark the engine oil tank level,let it sit down for a few days,then without moving the engine remove the hood and check the mark.
any lowering will mean either the oil pump shaft oring is leaking or the inline oil check valve is leaking.
however it is a two stroke that mixs oil with the gas in the VST, means after a hard run you have 50/1 in the VST.
shut it down before idling 30 minutes or so and this 50/1 is in the crankcase.
means as it sits and the gasoline evaporates it leaves a rich oil mix behind and it smokes on the next cold start.

[Strat_Yamaha250]

I will try that out. I had the boat parked for about 2 months and it started doing this after that. It was fine before I parked it. I knew it was going to be parked for a while so I went and topped off the gas tank and added Sta-Bil as instructed on the bottle. I also noticed that it has a loss of RPM's at WOT. It usually turns 5600 to 5800 and now it will only turn 5200. I didn't run it at WOT for more than a minute and noticed the RPM's were low so I backed off and didn't run it over 4,000 the rest of the day and shortened the trip because I didn't know what was going on. I stopped and started a couple of times to fish for a few minutes before I got back to the ramp and it smoked pretty bad for a second or two each time I restarted the motor. I also run ring free in it all the time and I run a shock treatment at least once a year then the rest of the time the normal amount recommended for maintenance. Could the injectors or the O2 sensor be clogged?

[mrpontoon]

check the low pressure fuel pumps,i have a 200 hpdi that had the same thing,yamaha told my to change the pumps 1 was bad it did fix it ,no smoke now

[Strat_Yamaha250]

Thank you for the advice, I will check into that.

[Tucker]

Mine have alway's smoked when cold. Can't think of any 2-stroke engine that doesn't when you start them up cold. Smells good...

[rodbolt17]

my 175 E-TEC is a two stroke and I have NEVER seen it smoke.
did toss #4 rod out of the block once, but never have I seen smoke.
however the OX 66 and the HPDI yamaha will smoke at start up.

[Strat_Yamaha250]

I wouldn't mind it if it was a small amount. It just started doing this after it sat up for a while. It used to put out a very small amount when it was started for the first time and then it wouldn't do it again the rest of the day. It a huge amount of smoke and it's doing it every time you start it. I ran it for about 30 minutes and varied RPM's from 2500 to close to 4000 and shut it down after letting it idle for a couple of minutes then 5 minutes later I started it up and POOF another huge cloud rolled out of it like it was trying to run on 2% gas and 98% oil. I'm going to take in and get it looked at. I've checked everything I know to check and can't find a thing wrong. Only thing I found was a loose spark plug cap on cylinder number 5. I pushed it back on tight then checked it after I got off the water and it was still secure. I'm going to pull the plugs out tomorrow and check them and do a compression check on all the cylinders, if I don't find anything it's going to a dealer to be looked at. Can anyone suggest a good repair manual and a place to get it from so I will have it for future reference. I think I am also going to pull the injectors out and send them off to be flow tested and cleaned.

[rodbolt17]

STOP
think on how the system works.
the oil AND gas is mixed in the VST.
the engine simply runs on this mix, sprayed by the 6 injectors.
think about your logic.
its not injectors NOR the O2 sensor.
trust me on that one.
I posted once already how exxcesive oil can be burned on an OX66 at start up.

[Strat_Yamaha250]

I forgot to mention I marked the oil tank on the engine like you mentioned above and it's only been a couple of days but it hasn't moved yet. I was really hoping it would be something simple but it doesn't appear my luck will be that good. I need to get a good manual if I am going to go any further with this as I don't want to start pulling parts off the motor or making adjustments to things in fear of doing more damage than good. I'm mechanically inclined to some extent but this motor seems to be much more complex than the older Mercury's I am use to owning and working on. Don't get me wrong I love my yamahammer but without some good schematic's I'm afraid to dive in too deep. Rodbolt, I know you are the man on these and actually you are the reason I got on here looking for assistance. You helped a friend of mine on his 2006 HPDI 225 when he had taken it to every shop in town and you helped him get his fixed the right way. We are a moderately small town and a good Yamaha mechanic is about as easy to find as a needle in a haystack around here. I'm in no real hurry to get this fixed because I haven't had the time to use the boat much and the weather is pretty bad. It has to be something simple because the boat was running perfect when I parked it.

[rodbolt17]

no worries.
however, ALL the oil that engine burns comes from the VST.
the oil pump combines ALL the oil,sends it through a check valve to the VST.
at the VST the oil and gasoline mix is transfered to the fuel rail where the injectors spray the air/fuel/oil mix.
the O2 sensor has jack squat diddly dumpkins do do with it.
infact at cold start, the O2 sensor has rumplystilkson jack squat to do with a dang thang.
ya gettin my drift yet?
at start up the ECU sees a signal from the ECT, it bases timing and fuel on the ECT,TPS and CPS.
about 113*F the CTS drops out and the ECU uses TPS and CPS signals.
but the oil pump is STRICTLY mechanical. the ECU has ABSOLUTLY NO control of oil.
see where this is leading?
either a seal is leaking, a checkvalve is leaking or its normal for your conditions.
my service manager is bitching about the same thing with his VX225.
however its how its run in his case.

[Strat_Yamaha250]

Can you recommend a good manual I can buy for the inner workings of this motor. You have definitely given me some more places to look. I went to the Yamaha home page and have been looking at there diagrams but I would like to buy a manual so I can have it to use while working on the motor. I saw on there homepage where you can purchase a Yamaha manual, I just want to make sure I get the right one.

Thanks for all the help.

[rodbolt17]

dude
sorry
NO manual will help you.
you either understand how speed density EFI works or your sunk.
just the way it is.
me? I have been to about all Yamaha schools since 2000.
good info, but it suxs.
the rest I learned on my own.
but I just described how your oil injection works????
is it me or you?
am I gonna get banned here too?