Please help. Carb issues??

Hello All,

I recently bought an mtd yard machines mower with a 18.5 horse intek single cylinder engine with a nikki carb. it was leaking gas into the intake and leaked if you shut it off. I took the carb off and noticed it had a lot of crud in it. I also noticed the fuel solenoid wasn't sticking out when it didnt have power ( I believe it sticks out when the power is shut off to block the fuel flow through the main jet.) With all that said, the gravity fed fuel was flowing through the carb because the needle wasnt seating correctly and the fuel solenoid wasnt blocking the flow.

I removed the carb, cleaned it, installed new gaskets. i put it in a vice in the same position its in when attached, hooked up some fuel line and poured fuel into the hose and it filled the bowl and the flow stopped. I'm sure the needle is working correctly at this point. Nothing leaked out of the carb at all. I then hooked it to the regular fuel line attached to the tank and nothing leaked. I hooked up the linkage and bolted everything down and turned it over, but it wont fire. If I put my hand over the intake, It runs for about about 5 seconds at normal speed and then dies. i'm not sure why its not getting gas with out my hand over the intake. Even though it leaked before I rebuilt the carb, it still ran. I know there is gas in the oil at this point and I plan on changing it, but I didnt think it would keep it from running. Any help is appreciated.

If you did not reset the float level, the cause of your problem may be a float that is too low, causing a very lean mixture. Also, I never clean and rebuild a carb without replacing the float needle and seat.

Thanks for your quick response. I replaced the needle, but the seat is part of the float assembly. I didnt see where the float is adjustable. Do all nikki carbs have an adjustable float? hopefully that is the issue.

The float almost bottoms out when the needle is fully seated. I read somewhere that it should be level when it seats the needle, but I'm not sure if thats the same for all carbs.

Here is a service manual which might help.

https://docs.google.com/file/d/0B6NaqjIxWV1ycG8wd0s3Z2Q2X00/preview?pli=1