Pony Motor Hight Idle and Leaks

Hello all,

I finally started up my D4 pony motor for the first time after a complete rebuild about a year ago. Unfortunately I have a few issues that I'm hoping you all may be able to help me out with.

1. Fuel leaking out of what I thought was the crankcase vent. Now I'm wondering where this vent passage actually goes. It's shown in this image, just under the right side of the mag. It's worth noting that I was not able to salvage the original felt packed vent so I replaced it with just a cross drilled vent cap.

2. I'm getting oil leaking out of the top of the dipstick tube after the engine was running for a few minutes. The oil level was correct before starting.

3. I have a very high idle, around 1800 RPM. I did a complete carb rebuild and cleared all of the passages, both adjustment screws are 1 turn off their seat - although turning both screws nearly all the way in and all the way out had nearly no effect on the engine. When I advance the throttle the engine gets to about 2300 RPM at about half throttle before dropping back down at full throttle. Here is a video with the engine at idle. It's worth noting that while I have the throttle all the way in, the governor spring isn't adjusted correctly and the throttle plate is resting against the idle screw which is also adjusted all the way in.
   
   Thanks in advance,
   Mike

Maybe the has an adjustment issue? sounds like to much fuel delivery and that plug/vent could be leaking it off?

They were just talking in a post last week about the carb on a pony engine being vented somehow to the crankcase. So you might do some reading, if you can navigate this horrendous site anymore. Just a thought

Check thread D2 pony kicking my ass on page 3 or 4 of the discussion forum. Might be relevant to you or lead you in the right direction. Good luck.

Dirtbiker, the main crankcase vent is into the carburettor inlet but there also is that vent on the crankcase top cover. Your symptoms sound like you have a blocked vent or too much blowby, especially blowing oil out of the dipstick tube. Try running it with the oil fill cap removed. If it runs better, then you likely have one or both of those issues. You could also have a fuel delivery problem - does it seem like it runs rich? If so, your float level might need adjusting, but it will be hard to adjust the carb with the crankcase pressurization issue if you have it