Hpdi 300 timming advance

[99yam40]

did you find some #s or did you have to count the revs?
Might help someone else down the line

[formula29]

I marked the flywheel and the prop, and counted the revolution, also the 300 has a water relief tube in it, and the 250 does not.

[boscoe99]

Actually, that is a cooling tube. It directs water to the hub of the propeller to help keep it cool.

[formula29]

I was having a tough time trying to figure out what the purpose of it was, I had never seen one before, any idea why only the 300 has it?

[rodbolt17]

the larger F motors have the tube as well.
its for prop hub cooling.
backyardigans strike again.
parts that physically fit yet wont work correctly.

bad thing is there are a lot of "professional" backyardigans.

[formula29]

3 months I have been trying to figure this out with the low rpm's, it never even crossed my mind that I could have two different gear ratio drives.