another won't start??

[Don McCombs]

You're on the right track, then. Don't give up.

[Glen]

Hi,
The spark can be a little too weak to fire the gas under compression, and still look ok, when you set a spark plug on the head with the wire connected to it, and make it fire there.

You didn't say how long since the points were replaced. If you don't want to buy new ones, I like to remove them, and set them on a solid surface and file them flat with a large file, wipe off all filings with a clean rag, and put them in again. They should have flat and shiny surfaces.
Just a suggestion, it sounds like you have checked the fuel system many times.

[tmays]

If you have fuel(and air) and fire as you say, then it must be a timing issue. And if you say you have timing correct, then it's time to go through it again

[siii8873]

what confuses me is this came out of nowhere, from running starting great just 4 days ago and now this????

Can't believe it's timing, ran so well and nothing has been changed.

[staninlowerAL]

If you pulled the drain plug on the bottom, you might want to unscrew the main jet and run a thin copper wire through it to make sure it's not stopped up.

You said in a couple of responses that you've cleaned the carb more than once but did you actually remove the main jet and clean it in the manner as Bob suggested? There are multiple orifices in the jet and one or more could be obstructed. Sometimes it takes more than carb cleaner and air pressure to do the cleaning job.

[siii8873]

Am I correct that the main jet can be poked out with carb in place. Remove the metering bolt from side of bowl and poke it out. What size wire should I use, One strand of a stranded copper wire?

[staninlowerAL]

Yes, remove the brass hex nut on the side of the bowl to get access, remove the main jet an use something like a copper telephone wire to check the orifices. Take care to not enlarge the holes.

[siii8873]

Got the cub started today and running great!!! It was a plugged main jet did the small copper wire thing and it turned over and started immediately. Thanks, do not know why it took me so long to try that, sure appeared that carb cleaned was flowing freely through carb.

[staninlowerAL]

Glad it worked for you. I think I learned this from Bob McCarty.

[tmays]

Got the cub started today and running great!!! It was a plugged main jet did the small copper wire thing and it turned over and started immediately. Thanks, do not know why it took me so long to try that, sure appeared that carb cleaned was flowing freely through carb.

Always good to check flow to carb. But that just means it's getting into the carb bowl. The main jet lets gas flow to the engine, so it doesn't show up in the flow test you performed

[bofahs]

I toss in a half-cup or so of SeaFoam with each tank of gas to prevent this. I also add about a half-cup of Marvel Mystery Oil to keep the valve guides in shape. Now, this all might be "elephant repellant", but I'll keep doing it!

[Randy Tuura]

I had starting issues one year with my 49 (I've been typing 46 a lot today by mistake). Anyway, wouldn't start no matter how much I cranked it. Don't know why, maybe a little bird told me to, but I pulled off the oil bowl on the air cleaner and it was not filled with oil - it was filled with dirty water with a little oil on top. I corrected that situation and it started right up.