Starting problems

[neverenoughx2]

I have twin 250 yam outboards. When I try to start the port motor the starter pops up but turns the flywheel very slowly. I switched the starters and same thing. I switched the starter selinoids and same thing. I disconnected the the starter and jumped it directly to the battery and it turned over fine. Any ideas????? I am stummped. I checked the cables also they looked ok.

Thanks Tom

[99yam40]

Measure the cables voltage drop while loading up or resistance as that sounds like the only thing left.

Did you jump Pos and Neg

[neverenoughx2]

Well I switched the batteries and the problem switched motors. God for bid I start with the simple solutions first. I just thought with the switch on both it would eliminate that problem. Oh well thanks