4825 DF Size

[Bud]

On the spec page, the 4825DF engine shows a bore of .85 and stroke of .8 and the size is .48. If you do the math with the listed numbers the size works out to be .45. So is the engine a .45 or is the numbers wrong on the spec page? If the bore was a .875 and the stroke stayed the same then the engine would be a .48. Also I am wanting to build an outbourd using the .48 piston and sleve if it is a true .48 size. My next question is will it fit the Pro outboard case?

Thanks,
Bud

[MECOA]

Pretty good that you caught that!

A little history on the .48 ducted fan engine.

K&B Havasu came out with the .48 ducted fan engine and used the marine 7.5cc (.45) piston/liner. However still called it a .48

When K&B Monrovia made the first batch of this engine it still used the 7.5 piston/liner. We did start on the larger bore cylinders (cylinder is the same as liner http://www.mecoa.com/faq/terminology/terminology.htm ) but did not finish the piston production.

Why not use the 48 piston/liner? The porting on the 7.5 is for high RPM and the aero .48 is for lower, less than 20,000 rpm.

Maybe we will finish the .48 DF parts someday, but I can't give you an estimate at this time.