Winter starting issue

[reinman88]

I hadn't checked for spark, but that's mainly because it won't start once and then will start fine the next 10 times. I figured if it was lack of spark the problem woud be the same every time.

The plugs are NGK 4768 FR2A-D

I have not tried to start it with the air filter out.

I just took a picture of the carb from the top. Will download it and post it here in a bit.

[reinman88]

Here you go.

[1989Marathon]

Is there a carb under there somewhere?

First, I would make sure you have spark, and not assume that it is always there. If you don't have spark, don't even worry about the carb or filter.
Next, I would try starting it without the filter. Maybe check to see if the filter is dirty. Then, I would spray down the carb to get it clean, and maybe close down the pilot air screw a bit.

[reinman88]

Yeah it's been pretty dusty this year, and 99% of my driving is dirt farm roads or dirt trails in the woods. That's in part why I put a new air filter in this past fall.

I will go out later this afternoon and check for spark, and if I have spark give it a try without the air filter.

What do you suggest I spray the carb with to get it clean?

May I ask what closing or opening the pilot air screw does?

If I turn this clockwise as you said, and count the turns. If it starts or doesn't start I assume I will want to return the screw to the same spot it was before I turned it.

[1989Marathon]

You can spray the carb down with carb cleaner.
Opening the pilot screw will give you more fuel on the idle circuit. Closing the screw will give you less. I believe that is just a plastic cap that is snapped onto the screw. The cap will limit the amount of adjustment. You can remove it if you have to. Just keep track of where the screw originally was. If it doesn't make a difference, put it back to where it was. I would see how far out it is currently.

[reinman88]

Went out and checked spark, which was good. I don't have any carb cleaner, but with a rag and a screwdriver I tried to get as much dirt off the carb as I could so I could see something. The pilot screw you pointed to looks to me to be black plastic tall and pointed at one end. I assume this is right. I kind of wiggled it back and forth, turning it a half turn clockwise, and then turned it back to where it was.

I pulled off the air filter, remember this is a new filter with less then 30 minutes of use. It took some time but I got a backfire, and then it took off. I replaced the filter and it started right up again. I did this three or four more times and it started and ran each time.

Now what did I just do? Or what is the meaning of what I did? lol

By the way thanks for all the help you have given me.

Edited to add.

Is it possible with me working on plug wires or something else, somewhere along the line I accidently moved the black plastic cover so the idle wasn't right, and by moving it back and forth that helped it to start?

[1989Marathon]

Put the old filter back in and see if it starts.
Or by "replaced the filter" do you mean re-installed the old one?

[reinman88]

I put in the air filter I bought last fall to replace the old one. This air filter has less then 30 minutes of driving time on it so it should be clean.

[1989Marathon]

Put the other filter back in and see if it starts.

[reinman88]

I threw the old dirty filter away last fall when I put in the new one.

When I got it started a little bit ago I just ran it 3 or 4 minutes. As I said it's 18 outside so I doubt 3 or 4 minutes get it warmed up that much. But I just went back out and hit the gas and it started right back up with no choke.