D-2Cat poney motor blow by thru oil fill. won't start

You need to provide some more details, and a few pictures wouldn't hurt. Where is the blow-by coming out? Is it in the cylinder fouling the plugs? Are the plugs wet with gas or dry? Tell us step by step what you are doing when you try to fire it up, and don't miss any steps!

4D2Ken, thanks for taking the time to help with this problem. The blow by is coming out the oil filler tube and some seems to come out the carb but I'm not sure.to start it I pull full choke and half throttle with no results.The plugs are not wet after I try this. I then put a small amount of gas dow the carb as I crank it. Still won't start. Then shot a small amount of starting fluid in as I cranked it,got some blue smoke but still will not start.It seems like it can't pull full down the carb.

If the fuel was left turned on the crankcase may be filled up with gas. Change the oil, make sure the oil level is correct.

G

Rich, I also have what appears to be a bit of blow-back at the carb - seems like the intake valve is shutting a bit late. I'm going to check valve lash to see if that's the problem. It also runs a bit retarded I think which might be contributing to my issue so I'll see if I can open up the gap a little to advance the spark.

Cheers,
Neil.

[quote="Neil"]Rich, I also have what appears to be a bit of blow-back at the carb - seems like the intake valve is shutting a bit late. I'm going to check valve lash to see if that's the problem. It also runs a bit retarded I think which might be contributing to my issue so I'll see if I can open up the gap a little to advance the spark.

Cheers,
Neil.[/quote]

Neil, thanks for the info. How do you check for valve lash? Could any thing else just be stuck or could something be broken or both?

It sounds like you may have more than one problem. But I would start by doing a search out here on pony carbs as there are several threads that address plugged passages, which I am sure you have. You will have to take the carb apart to clear the blocked passageways - I posted some pix a while back. You only have 40psi on one cylinder, which is way low. You can squirt some crankcase oil in the plug hole and then test compression again (with throttle wide open). If the compression goes up you have worn rings, if not it is leaking through the valves. A quick way to see if your timing is way off is to take the plugs out and squirt some starting fluid directly on the electrodes. Re-install the plugs and see if you get a pop or two out of the old gal when you crank it. 40psi may not be enough compression to fire, but 80psi should. On a lot of the old pony engines you have to play with the choke and throttle positions to see where it runs best, especially if you have some blockage internally.

It sounds like you may have more than one problem. But I would start by doing a search out here on pony carbs as there are several threads that address plugged passages, which I am sure you have. You will have to take the carb apart to clear the blocked passageways - I posted some pix a while back. You only have 40psi on one cylinder, which is way low. You can squirt some crankcase oil in the plug hole and then test compression again (with throttle wide open). If the compression goes up you have worn rings, if not it is leaking through the valves. A quick way to see if your timing is way off is to take the plugs out and squirt some starting fluid directly on the electrodes. Re-install the plugs and see if you get a pop or two out of the old gal when you crank it. 40psi may not be enough compression to fire, but 80psi should. On a lot of the old pony engines you have to play with the choke and throttle positions to see where it runs best, especially if you have some blockage internally.

I have 40 psi on one cylinder of my pony and it fires and runs ok. one day i am going to pull that head as its not a big deal and give a look inside there.