2002 225 OX66 Smoke/Rough Idle

[Suncoug]

I have a Hydrasport 2596 with twin Yamaha 225s. The port motor runs great except that it runs rough and smokes quite a bit at lower rpm up to about 1000 rpm. The warranty just expired and it was a bit behind on maintenance anyway (I got the boat not too long ago). So, I have done the following to address this issues but so far it is doing the same:

1. O2 sensor/Pickup Tube replaced
2. New Spark Plugs/Caps installed
3. Ajusted the oil rod
4. Replaced all three low pressure fuel pumps
5. Changed fuel filter
6. Changed Pressure Relief Valve/Thermostats/Impeller

I have swapped ignition wires/coil from the starboard motor to no avail. Oil consumption is quite a bit higher on the problem motor and the sparkplugs from it look quite a bit more oily than the other one, so I am convinced that it is related to oil control. I am fairly certain that the oil rod is set up right. I suspect that the oil pump is messed up. I would love to get your thoughts and I would also like to know how difficult it is to get it replaced. I have a Yamaha factory manual but it doesn't talk much about how to replace the oil pump.

 

[Suncoug]

Re: 2002 225 OX66 Smoke/Rough Idle

BTW, I use Yamalube and Ringfree.

 

[rodbolt]

Re: 2002 225 OX66 Smoke/Rough Idle

the oil pump shaft seals can leak and allow crankcase pulses to pull oil directly into the lower cylinders, the seal and oring are easy to replace.

 

[Suncoug]

Re: 2002 225 OX66 Smoke/Rough Idle

So, is it highly unlikely that it is the oil pump that actually is messed up? Also, if the seal and oring are the culpits, wouldn't just lower cylinders just get fouled? The spark plugs look the same in al cylinders. Thoughts?

 

[rodbolt]

Re: 2002 225 OX66 Smoke/Rough Idle

the puddle drain system will distribute the excess oil all over.
the pump itself is almost bullet proof.
its also possible an oil line check valve(s) is bad, easy to test with a vacum pump.
look on the yamaha parts web site and you will see the orings and seal assy.

 

[Suncoug]

Re: 2002 225 OX66 Smoke/Rough Idle

Thanks a lot for the info. It makes sense. Do I need to prime the pump or anything? BTW, the previous owner recently told me (after selling the boat) that excessive smoking/rough idle has been a problem for long time and he coundn't get it fixed under warranty basically since new. He said he got rid of the boat because he could never fix it. Is there any other condition other than the causes that I am looking at that would cause this?

 

[rodbolt]

Re: 2002 225 OX66 Smoke/Rough Idle

the oil pump has to be bled as per the service manual. as far as causes anything that can make the air/fuel in the cyl rich or make the oil to fuel mix rich can cause it to smoke.
I dont know why it was not fixed other than to many techs are scared to actually troubleshoot an issue.
a simple oil consumption test would tell you if it was using to much oil. however the yahama manual only shows an oil output test and to many techs cannot reverse it.
for example if the book says the output should be 20cc in 3 min at 1500 with the pump wide open and the tech runs the output test and its correct he still does not know the oil consumption,only the output.
however if I plug off the oil intake pipe on the engine tank and insert my glass pipe in the oil line to the pump and fill the pipe to my marks and rerun the test and see that the consumption far exceeds the output then bingo I know what the issue is.
oil output tests are wonderful I guess but I like to do consumption tests.
what I do is not rocket science and its embarresing to charge for it sometimes but it does require thought.

 

[Suncoug]

Re: 2002 225 OX66 Smoke/Rough Idle

Many thanks for your help and insight. I took the oil pump out and at least visually it doesn't look like oil is leaking from it, but I guess doing the test you described above will confirm it. One thing I noticed is that it look like the oid pump on the problem motor seems to have quite a bit of corrosion from saltwater, though the other one looks really clean. I found that the plastic bracket that holds a couple of hoses right below the oil pump came off due to improper rigging, and salt water came through two holes that are about 3mm in diameter. I put some silocone on it to prevent further damage.

Not sure if this has anything to do with it, but I am going to replace to oil pump, as I need to get my boat ready for the fall tuna season soon. It also looks like the oil rod may have been bent by someone. There is quite a bit of play between the plastic coupler that connects to the oil pump. I think replacing it will help.

Again, many thanks. I will report back and let you know how it went.

 

[Suncoug]

Re: 2002 225 OX66 Smoke/Rough Idle

Well, I have replaced the oil pump, but the same problem persists and I have other issues arise as well.

I replaced the existing oil pump with a brand new one. Bled it per factory manual. At first, all seemed to be well. Once the bleeding process was done, the motor was idling well without the smoke or shake.

However, the idle speed was irradic. it was fluctuating between 600 to 900 rpm, where as the other motor was at constant 600 rpm. More importantly, I could not get the motor go higher than 3000 rpm. Plus, at all rpm levels, the problem motor was burning 2X fuel per Yamaha fuel management than the other one. Even at higher speed, the rpm was irradic, jumping up and down.

I figured, well, a new problem deal with but at least I fixed smoking issue, but it started smoking again, as I was coming back to the marina.

I am at a loss to what may cause issues like this. The only dealer that has a good reputation has 6-week backlog and won't be able to take a look at my motor. Help!!!

 

[zzzzz]

Re: 2002 225 OX66 Smoke/Rough Idle

try swapping the CDI units from engine to engine to see if you can "transfer" the problem.... then hope its not the CDI = $1273:% 8)

 

[Suncoug]

Re: 2002 225 OX66 Smoke/Rough Idle

Actually, when I had the cowling off, it sounded like there was some arcing, but I wasn't 100%.

 

[Suncoug]

Re: 2002 225 OX66 Smoke/Rough Idle

Could a whacked TPS cause this?

 

[Suncoug]

Re: 2002 225 OX66 Smoke/Rough Idle

I wonder if I disconnected something while working on the oil pump. Any thoughts?