smoke coming from muffler after overhaul

Hi All,

I have a Craftsman Push Lawn Mower (model # 917.376470) and I've attached a photo of it. It has a key start system as well. It wasn't starting so I decided it was time to do a complete over haul on it.

I put in the new following parts:

1. carb
2. breather valve
3. air filter
4. spark plug
5. ignition coil
6. brake
7. brake cable line
8. flywheel key
9. oil change (20 ounces)

When changing the parts I removed the entire key start system. Its old and doesn't work anymore anyways.

After dropping in all the new parts, it starts up great now but I noticed within 15-20 seconds the muffler starts smoking (looks like vapors coming out of it after I turn it off) and it really concerns me. I did tip the lawn mower over when working in a few directions. Is my problem that the engine is running too lean for some reason or do I need a new muffler? I'm hoping its not something too serious after doing all this work.

Or does the carb need to be adjusted in someway?

Thanks!

Run it for 20 minutes or so and the smoke should stop.
There is no drain for the muffler so if oil ran into it you just have to wait for it to all burn off.
So it should start to smoke as the mower warms up it shoudld get worse than after a while the smoke should start to subside.
It can take several hours for all of the oil to burn off.

OTOH you can take the muffler off, wash it out several times with fuel and refit but it will still smoke till whatever you washed it with burns off.

I'm with Bert. Just let it run a bit, should clear after 5 - 10 minutes.

Thanks for all your help. It took 5 minutes to clear it all out. Its working well now.

I think that is enough of an overhaul for now. Probably in the Spring I'll clean out the valves area and put in a new head gasket. :laughing:

topgun129 said:

Thanks for all your help. It took 5 minutes to clear it all out. Its working well now.

I think that is enough of an overhaul for now. Probably in the Spring I'll clean out the valves area and put in a new head gasket. :laughing:

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My advice is if it is running good and not leaking anything leave it alone.

yea i think you are actually right. probably better to leave it be. :thumbsup:

At the end of the season you run the tank dry, change the oil then leave it for the next season.
At the beginning of the season sharpen the blades 9 cause they will rust during the off season.