Starting Issues after Rebuild

[Collin Potts]

Hello! I own a 1990 superjet 650 square nose that was purchased at the end of last summer and it was having issues where it would only run for a few minutes before bogging down and dying out. I discovered that the base gasket between the block and crank case was missing a chunk and blowing oil out the side of the engine. I just completed rebuilding the engine and replaced the carburetor along with all of the seals however it still is having issues starting and I don’t know what is causing it. I know the compression is good at around 150. If anyone has more knowledge or knows what would cause this I would appreciate the help.

 

[Kohldanielzimmer]

“new carburetor”. Was it starting okay before ?

Was the new carb properly jetted and correct pop off pressure used?

 

[Collin Potts]

It wasn’t starting well at all before the rebuild and before I found the gasket leak I thought the sputtering out was due to an old carb and lack of fuel which is why I replaced the carburetor with a new mikuni 44mm carb. I didn’t mess with any internal settings for the carburetor and after reading about it is likely my issue. I know how to set the high and low idle speeds but don’t know much about the pop off pressure or jetting and from what I have read I have to take apart the carb to figure that out. Thanks for the advice though I will read more about it and hopefully get it running well soon.

 

[Kohldanielzimmer]

Complete rebuild and new carb is quite a few variables but if you have good compression (you said you did, no massive air leaks,and spark I’d suggest focusing on the carburetor.