Re: 1965 johnson 40 hp sudden power loss
Yeah, if you've got a problem it's probably up in there. If it's a crankcase sealing issue, the only likely leaking spot would be the top crank seal which will also be visible with the flywheel off.<br />But I don't think that's the problem since it normally gives you an awful idle and doesn't affect WOT much.<br /><br />The thing about cracked coils and spark plug wires is the magento works harder and generates higher voltages as the RPMS increase. So often what happens is it won't arc over at low rpms and it runs fine, and then as the rpms pick up it dies. The engine slows a bit, and then it starts firing again. <br />Now sometimes that cylinder will 'mysteriously' kick in and out, giving you a sudden boost. So I'm still suspicious of something strange. Coils are the most likely candidate.<br /><br />Also, if you don't mind, trace the wire that comes off the center of the vaccuum cutout switch. It ought to run to the set of points that operate the bottom cylinder (the aft ignition coil). Wouldn't mind ruling that out.
Yeah, if you've got a problem it's probably up in there. If it's a crankcase sealing issue, the only likely leaking spot would be the top crank seal which will also be visible with the flywheel off.<br />But I don't think that's the problem since it normally gives you an awful idle and doesn't affect WOT much.<br /><br />The thing about cracked coils and spark plug wires is the magento works harder and generates higher voltages as the RPMS increase. So often what happens is it won't arc over at low rpms and it runs fine, and then as the rpms pick up it dies. The engine slows a bit, and then it starts firing again. <br />Now sometimes that cylinder will 'mysteriously' kick in and out, giving you a sudden boost. So I'm still suspicious of something strange. Coils are the most likely candidate.<br /><br />Also, if you don't mind, trace the wire that comes off the center of the vaccuum cutout switch. It ought to run to the set of points that operate the bottom cylinder (the aft ignition coil). Wouldn't mind ruling that out.