Johnson 70hp vro 1990 carb issue

[Malu]

Hello! Im new johnson outboard user here in cold Finland. Is it ok to put 60hp johnson 1988 carburators to my 70hp engine?? Im taking vro off and mix fuel. I have really good shape 60hp carbs and i wondering if i take orifices from those old 70hp carb to these 60hp and put it on to engine??

 

[WernerF]

Just switching orifices don't work. The 70hp carbs have a bigger throat diameter than the 60hp carbs. But you can put the complete 70hp carbs on your engine. Unfortunately the 1988 70hp carbs have no idle mixture adjustment scews what makes idle adjustment difficult, especially if the engine isn't in perfect shape.
If the propeller is chosen to the upper rpm range at wot, you might need another pitch propeller with 70 instead of 60hp.