56 johnson 5.5 cd12

[dpasquill]

I have a cd12 5.5 Johnson I am trying to get running. I have checked the points (they are good) and replaced the coils. I am getting a good strong spark. I removed the carb and cleaned it and installed a new carb kit. I have the low speed set 1.125 turns from the seat and the high speed 0.5 turns from the seat. The motor starts and runs after I pump pressure into the system. It will run at "start" on the throttle and above for about a minute. Then it accelerates, then dies. It also will not run slowly. If I pump the pressure on the tank as it accelerates it will slow down and run for about another minute. <br /><br />Help<br />Dave

 

[petryshyn]

Re: 56 johnson 5.5 cd12

Hi<br />Sounds like you're running out of fuel. The tank is a pressurized system. If the filler cap is loose, it won't pressure up to force fuel from the tank to carb. There are also check valves in the tank that may be bad. They are in the same assmy. that the hose connects to. <br /><br />Good luck!

 

[jegervais]

Re: 56 johnson 5.5 cd12

I agree with schematic, sounds like the fuel tank is loosing pressure. As it looses pressure (and subsequently fuel flow to the motor) it causes it to "lean out", thats why the rpm's pick up. The seal kits are still available for those old pressurized tanks, there may be others that carry the kits, but I know you can get one from American Outboard Motors (www.americanoutboard.com). They deal with mostly 1965 & older motors, a huge selection of stuff.<br /><br />-John

 

[alcan]

Re: 56 johnson 5.5 cd12

Hi David<br /> As schematic stated you have a presurized fuel system. There can't be any leaks in the tank,hose or connector. The good news is that you can repair all these things by replacing all the rubber stuff and cork gasket. The connector o-rings are quite often bad. Another common one is the rubber gasket on the filler cap. You can also convert to a fuel pump.