1999 Yamaha PX150TLRX Ox66 Issue

[Jbranham]

Hello,

New to BBC but I found the Yamaha section and thought that maybe I could get some ideas here before I take the motor to a Yamaha dealer.

So......

I decided to learn and do all the yearly maintenance myself this time and keep in mind the motor ran flawless before I performed any of the maintenance.

What maintenance I performed:
1. Rebuilt Tilt and Trim (works great, no issues)
2. New lower unit oil
3. Checked prop and re-greased splines and shaft.
4. Changed main element Filter
5. Changed VST Filter
6. New spark plugs
7. Cleaned O2 Sensor w/new gasket
8. New in-line Fuel/Water separator

Now...

The motor is really not running well at all now. Acts like a carbureted motor with low/rough idle and lot's of smoke. Won't stay running when I start it up and now I have to give it throttle to get it started and keep it running until I can get it in gear or it will die on me. It's idling terrible as compared before I did the maintenance.

Don't know if I could have messed something up, did something wrong, or what but before I take to a mechanic I wanted to see if anyone may have an idea or have run into something like this before.

Thanks,
Jason

[Rich Z]

Have you gapped the spark plugs to spec for your motor? Also, ensure the filter element on the clear bowl is installed correctly with new o-rings and container is not cross threaded.

[Jbranham]

I gapped them compared to the ones I took out. But I may have not done this properly.

I did install a new o-ring on the filter container but I will check to see if I possibly cross threaded.

Someone already mentioned to me about the gap on the spark plugs, didn't fully understand this would cause a major issue.

Where can I find the specs on the gap?

[Rich Z]

There should be a decal on the upper pan showing correct spark plug and gap. I know what it should be for a 3.1L motor but yours is a 2.6L and i dont have the spec. You maybe able to find it on line somewhere. It will run rough and foul plugs if gap is too tight.

[Jbranham]

Ok, I will look for the decal and check that. I appreciate your help.

[Rich Z]

If it calls for ngk br9 or br8 plug gap it to
.039

[Jbranham]

BR8HS-10 - NGK Spark Plug is what it is saying.

[Jbranham]

What I'm finding is a BR8

[Rich Z]

Verify correct gap, check the fuel filter for proper installation than go on to the low pressure pumps (lift pumps) and ensure the diaphragms are not leaking fuel. Research here on how to test the lift pumps.

[Jbranham]

"Research here", was there a link intended or just on this forum?

[Rich Z]

Look at top of yamha forum page for "Repair links"

[MichPhoenix77]

Maybe you need to replace the O2 sensor. Cleaning it might not be enough.