LU Interchangeability

[*EdC*]

Guys,
I have crack in LU on my 1970 800EL. Thought I'd look around for a replacement before trying to weld it. The only number I could find on the unit is 1623-3909. Not sure if that's a casting number or a part number. Any way can some one tell me what years may inter change with this one. It has a thunderbolt ignition and no preload on the drive shaft. Believe it to be a 2:1 ratio..... Will 2.3:1 work also?

Thanks, Ed

 

[Chris1956]

Re: LU Interchangeability

Ed, Just about all of the inline six LUs from the 70-90s will fit. Most of these have a 2::1 gear ratio. The Merc 850 had a 2.3::1 gear ratio, so you might like to check yours closely. I think the gear ratio difference can be overcome by a prop with a 2 inch pitch difference.