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1985 Evinrude 20hp just will not start.

R

rohrbachj

New member
The power head was just rebuilt, re-bored for oversize pistons, new rings, head re-grounded, many new parts. Has very good compression in both cylinders, and good spark. Carb cleaned and rebuilt. Electric start and electric choke work fine, but it just will not start. If i put some fresh fuel directly into the cylinders via the spark plug holes, all I get is a back fire. I think the throttle linkage is synched adequately, but I don’t know what else to adjust at this point to get it to start up. Any tips in what to do are greatly appreciated.
 
Plug wires are on the wrong cylinder.-------Or wires from cd to coils are wrong.----Top cylinder must have orange / blue stripe wire to the coil.
 
Also check the main throttle linkage. When you twist the throttle to start. The main baffle has to open slightly. Often in an older engine the roller on the timing plate doesn’t move the baffle enough to let the fuel and air mixture through. The spring on the side of the carb gets worn out and the adjustment screw often doesn’t have enough range. Try to hold the baffle open in the main carb opening. Even if it’s held by pliers by a second person. See if it starts then.
 
Hey there! As I see, the spark plugs are firing, but the fuel is not igniting properly.
Firstly, I would check the fuel pump to make sure that it's working correctly. If you have a fuel pressure gauge, that could also help diagnose the issue.
Another thing to check would be the timing. It's possible that the timing could be off, which would cause the engine to not start...
 
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