I have an OS .15CVRX that has about 2 gallons of fuel through it. It has never been run lean and still has lots of compression even when its at operating temperature.

The first time it is started for the day it starts on the 2nd or 3rd pull. However every time after that it takes at least 10-15 pulls to get it going. It doesn't matter if I let it cool or not before starting.

The other problem I am having is that sometimes it will be running great and then go really rich and bog down for a few minutes. The it will go back to normal on its own.

Can an airleak at the carb or backplate cause either of these problems? The engine does not overheat. When it is running good the temp is around 210-230. I have replaced all of the fuel line already and it didn't make any difference. Would resealing the carb and backplate help? If not, what else could be the problem?

Thanks,
Chris

Yes i would re check all the back plate gaskets, and the one around the carb. I would also sugest you try to turn the engine over with your finger, by turning the fly wheel. If there is little to no resistance, then you need a new piston an sleeve. Also check you glow plug, it could be fowled out. Also make sure that the head screw are tightened down properly. if there tightened down improperly,this could also be a leading cause of you problems. If you have any more questions just ask.

Check the head screws