Re: 90hp carbs on 75hp
Don't know. Manual says that WOT rpms are 5000 nominal on the 75 and 5250 on the 90, both +/- 250. Timing setup for the 75 is 18 BTDC at 3000 for the 75 and 20 for the 90. This extra couple of degrees goes with the higher rpms for the 90 and makes sense. Plugs for both are the same.
My manual lists the WME Carburetor, number being stamped on the side of the carb. After the WME is a number . For different years of manufacturing, they used higher number carbs, like going from 30 to 80 but that was for engines from the 60 Jet,75, 90, 100,115 Jet, and 125 hp engines over several model years (lots of variations). Basically the jet size listed goes from .052 for all carbs on the 75 to .062 for cylinder #1 to .064 for # 2 and 3 and remains pretty much constant over all those models. Don't know what other changes may have been in order, like a venturi size change, mounting hole change sort of thing.
The jets have to be the high speed jet as the low speed is variable with the set screw.
So he may know what he's talking about. Professional guys on here will probably pick up on this and tell you for sure.
Best I can do.
Mark
