Oil & Fuel Smoking when cold started

[Pacifictimes]

I bought this T5C a couple months ago, it had about 1400 hours on it now. It was poorly maintained, but heavely used. I found the engin (honda 20 hp) oil blacker than black and a little low, not dangerously but low. So I replaced the oil and filter with recommended products. So after about another 6 or 8 hours of run time I started noticing on cold starts smoke bellowing out, in 5 or 10 seconds after its running the smoke clears and all's will. . . Was there some STP in the old oil? Am I doing something wrong, and screwing up my machine? I am a complete novice, but very mechanical, what's up?

 

[amaxwell]

:thumbsup:Are sure you used the correct weight and class of oil? Has the temps. changed since you started seeing the smoke? Some times diesels smoke a little from unburned fuel when cold,as long as the fluid levels stay stabil you are probably ok. Maybe someone who is more experinced than me has more ideas.

 

[Pacifictimes]

This little motor is gas, and the temptures here are very stable around mid to upper 40's F.

 

[Transit]

Sounds as if the rings are worn or may be sticking until the engine warms. What does the new oil look like now with a few hours on it? Are the spark plugs wet with oil? You may have to live with it or rebuild.

 

[Pacifictimes]

I am actually ok with living with it, just want to make sure I am not doing some novice, blatent dumb thing to screw up this little tractor (I love it).
The oil is a little dirty right away I am sure it is washing the walls of the crank case of all the impurities left from the oil change, I will change it again after a few more hours. I believe this unit being about 1400 hours old and with the data I can find on it is about a 1999. I am thinking the valve seats and valves themselves may be worn because of age and dirty oil, am wondering if these are adjustable, or not, or weather I should even consider something like this. Also if needed what does it take to replace the valves and seats?
It only smokes for a matter of seconds, not a big issue, my bigger issue is that I don't mess up this little motor, it seems to work great.

 

[kjung17]

I'll assume that the smoke is blue-grey as opposed to black or white. It is likely that the valve stem seals are leaking. When the engine is shut down, the worn seals allow oil to seep into the cylinder. When you start the engine, this oil is burned off, creating the "smoke on startup" situation. Replacing the seals is a simple operation, if your heads are easily accessed. Although, I would not worry about replacing the seals at this time. This condition will not harm the engine. If you monitor your oil level, I think you will find that very little oil is being lost.:thumbsup:

 

[TracTrac]

I'll assume that the smoke is blue-grey as opposed to black or white. It is likely that the valve stem seals are leaking. When the engine is shut down, the worn seals allow oil to seep into the cylinder. When you start the engine, this oil is burned off, creating the "smoke on startup" situation. Replacing the seals is a simple operation, if your heads are easily accessed. Although, I would not worry about replacing the seals at this time. This condition will not harm the engine. If you monitor your oil level, I think you will find that very little oil is being lost.:thumbsup:

^^^correct^^^

This is an air cooled engine. People often think air cooled means maintenance free. An air cooled engine operates around 100F hotter than a liquid cooled. If the air flow is blocked from dust, wasp nest, grass clippings ect. things get real hot. Remove the schroud and clean the cooling fins. While this won't fix your valve seals it might add another year to the engine.
A dirty air filter causes a rich condition which produces excess carbon deposits.
If the engine still cranks easy, doesn't use too much oil and doesn't knock just run it. Run it fast, air cooled engines need the extra air flow.
You might luck up and find a good used Honda engine cheap.
Can't beat a Honda. I personally watched a contractor run a 13 horse generator for one year only adding gas and oil. Oil was only added when it shut down from low level.

 

[Pacifictimes]

Man you guys are the Greatest, my thanks for some great info, I will look into the air flow issue, I looked at the air filter it looks like replacing would be good, I took it to a local auto parts store with no luck, will take it to a local tractor dealer/service dept.
It starts great and runs good, I do run it pretty much full out which does not sound to be over reving the engine.
The heads are easly accessed should be no problem, but I don't (yet any) see any real oil useage, I will keep a close eye on this though, to new to me yet.
Any suggestions how/where I would look for a back up Honda?
And if needed could I go to a local motorcycle (Honday) shop and buy the parts needed to replace these valves/seats?

 

[kjung17]

I'm not sure if the motorsickle guys support the small engines. A quick phone call would answer that question. I think I would start with a small engine repair facility. I wouldn't worry, too much, about finding a spare engine. Keep that little engine clean and you'll have years of trouble free operation. Those Honda engines are very reliable.

As a side note: I recently replaced the generator on my service truck with a John Deere unit powered by a Subaru engine (6 hp). I didn't even know Subaru made a small engine. So far, very quiet and easy to start.

 

[Pacifictimes]

Thanks so much for the great input, I really appreciate all the help.:thumbsup: