Yes as Robert says, and if you use the magneto you have be sure to check timing on both cylinders, it shouldn't differ much. If it does the breaker cam is scrap. But inconsequent timing during run, and hard to tune the timing so the engine is running right can have other causes in a magneto, than a ignition cam.
The 37ci should start and run fine with a set and fixed timing of 7/32" or 5,5mm btdc per instruction on the earlier 37ci engines. Many runs fixed timing. But if you want to use the handle, at minimum advance, restrict travel at the lever so it does not ignite after top dead center. Not more than a mm atdc anyway, it can be difficult to adjust that to tdc exactly. The exhaust valve gets too hot with timing atdc.
Not often you need to tune the timing with the handle during run with a 37ci engine, just perhaps only to lower the idle speed when going into first gear from stand still. Other times always run on full advance.
With max advance of 7/32" the movement between max and min advance at the handle is so small so it is easy to forget and accidently run with ignition retarded so I would concider run fixed ignition on a 37ci if I can get a low and stable idle. With 5/16" or further advance the range is larger and in some occations (high load, low revolutions) the engine is labouring or running better if timing is adjusted at the handle.
I think! it was a bit earlier timing in the instructions on the later 37ci engines, max 5/16" or 7,9mm, same as Prince and 45 Scout timing. Others may reply what timing they use.
