Brainstorm 2-stroke bogging with me....

[Pablo]

First clear your mind of everything, last night's beer, women, house payments, etc

OK now: Say you have a new 2 stroke engine that starts happy as a lark with full choke when cold. But is very cold blooded. Takes 10 minutes to get warm and runnable, but choke still needed. Seems to have sufficient power, but is still breaking in.

Runs fine for 30 minutes at almost full open choke, but still need to be ginger with the throttle. Then when engine is hot, can not go to full throttle or engine bogs and drops right off.

Am I too rich or too lean?

[deacon]

Is this multiple choice... LOL someone a lot smarter than me will have to guess. Usually they say look at the plug to tell which. Are you sure you don't have an air leak. Seems like you are cutting off the air with the choke to compensate for air leaking into the system, but hey I make no bones about not knowing what the heck I'm doing.

[Bikeguy Joe]

Sounds like you have an air leak somewhere fo' sho'.

You can have symptoms of an air leak if your base gasket is leaking too.

[deacon]

Check the carb screws for tight as well as the bolts on the manifold. Don't forget that pesky the connection between the carb and the manifold.

[Pablo]

I think you guys are correct. Unless there is something defective about the main jet the engine should do fine at full throttle, fooling with the needle won't or should not change full or near full throttle behavior.

All bolts are tight, gaskets look good.

Before I go messing with anything else, I'm gonna seal the carb to manifold interface with automotive RTV and get a better clamp.

Originally Posted by Bikeguy Joe

You can have symptoms of an air leak if your base gasket is leaking too.

Please explain "base gasket".

[deacon]

If you haven't sealed that connection with either an o ring or sealant then it's the most likely place for an air leak.

[Bikeguy Joe]

Base gasket is the gasket at the bottom of the jug, kinda like a head gasket, except it's a little lower and made a little different.

[deacon]

Why isnt that called the foot gasket if the one on the other end is the head gasket lol

[Pablo]

Originally Posted by Bikeguy Joe

Base gasket is the gasket at the bottom of the jug, kinda like a head gasket, except it's a little lower and made a little different.

Got it - I was thinking that, but wanted to make sure. Looks OK from the outside.

Weather report: Raining like crazy.

OK so NOW I also know what you guys are talking about when suggesting adding an O-ring. I pulled the carb and sure enough, yes indeed I put a 5/8"x13/16" O-ring from my trusty O-ring kit inside carb and whilst pushing the carb on to compress said O-ring, I tightened the clamp. IT MADE A LARGE DIFFERENCE!!

But, Weather report: Raining like crazy.

It started right up and SOUNDED way more healthy. Reved OK, still cold.

Weather report: Raining like crazy.

Back in the garage, no Automotive RTV in stock. Why?

Even with the O-ring, the four splits in the carb flange and the general out of roundness of the manifold and the carb flange allow air leakage.

Weather report: Raining like crazy.

[Pablo]

Originally Posted by deacon

Why isnt that called the foot gasket if the one on the other end is the head gasket lol

I was thinking butt gasket, but that might get me banned.

Don't ban me, bro.