After a few years away thought it was time to get back into the hobby. Ordered the RCMK four bearing case a new hot pipe and the 1018 carburetor . Every thing went together without to much of a problem. I have blue spark, new fuel and compression. Can't get the G26 to run or even fire with the assist of a little fuel primed into the cylinder? Tried changing plugs and grey coil but still not even a back fire!

Check to see if the flywheel is lined up correctly.

If I can remember correctly there is only one key way slot in both the fly wheel and crankshaft. My first thought echoes yours in the timing is off or I don't have the red coil and mag gapped properly.

gap specs in this thread

modelgasboats.com/forum/14-mgb...-testing-coils/

You have fuel, air and spark It will fire. Check to see if the carb. is opened a little , it might be closed and it won't run .. Put your finger over the carb. and pull the starter rope slow ,if your finger gets wet with fuel great. Good luck.

It's probably a 1048 ( not 1018 ) carb, and make sure your needles are set properly. When hand choking, it's easy to over-do it and flood the motor.

Did you purchase a rcmk right hand case or flywheel ?

Be sure there aren't any air leaks in the crankcase. We once found an engine (not RCMK or other well known brand) with the casting like the picture below.

Lohring Miller

Try. Take off your fuel lines, Then you know there is no fuel going to the engine. I Blow some air into the intake. While pulling on the starter. To clear anything left over in the crankcase. Test your spark again. Now you should have a dry motor with a good spark. Spray a > Very< small bit of carb cleaner in the intake. Throttle wide open see if it fires off. If it does, fuel probs. if not>>>>>>

Make sure there is not some thing in the exhaust pipe may be a paper plug or some tape over the exhaust port that you might not removed ...