rockytop93
Seaman
- Joined
- Apr 25, 2003
- Messages
- 64
'75 merc 650 starts fine idles ok. when pushed to wot surges as it is running up to full rpm. At wot runs fine for a few minutes, then slows down suddenly to 2500 to 3000. moving throttle back and forth will not get it to speed up. Will be ok after sitting for a while, then same thing all over again. Choking causes it to die down, fuel prime bulb stays hard. New plugs.<br /> have taken carbs apart and cleaned. One thing, when testing coil first two tests in manual ok. Third test, tester between coil tower and ground showed nothing. Book says 57-74 ohms. If coil was bad wouldn't it cause problems at all speeds? How about stater in dist? Compression good all three clys. Has good spark all cyls. Hope someone can help