1972 Johnson 20 hp

[amvaneyk]

Every time i try to start it there is a loud back fire noise. The spark plug wires are on correctly, the fly wheel is torqued down correctly and the key is not stripped out on the fly wheel. I don't really know what else it could be. The Carb has been overhauled. Any suggestions??

 

[oldcatamount]

Re: 1972 Johnson 20 hp

You have a timing problem. Check the ignition points for proper gap. Then do a "link and synch" adjustment where you align the timing mark with throttle roller and check to see if the carb butterfly starts to open when the roller reaches the timing mark. If it doesn't, adjust the throttle linkage until it does. sometimes need to do it a couple of times to get it correct. But, check your points first!