islandboat
Petty Officer 2nd Class
- Joined
- Apr 10, 2004
- Messages
- 127
I've got a 1998 50hp johnson 2 cyl that will not idle. That was and still is the primary issue. The carbs are very clean. They had 2 stroke oil backing up into the carb bowls because the vro pump was allowing the oil from the oil tank, which was holding pressure, to flow into the carb bowls when the engine was not in use. It had oil all the way back to the remote fuel filter. When the engine was started every few weeks, it would smoke really bad and sometimes foul the plugs. It had oil running out the exhaust and down the skeg and leaving a large puddle under the foot (not foot oil). I had to fix that. I removed the vro pump, pulse valve, and installed a fuel pump from an older model 48 special onto the side of the block. Fuel pressure is good and the new fuel is mixed with the 50:1 ratio.
I disassembled the carbs. They looked like new inside. I did not replace any of the gaskets, yet. I notced that the carb covers were warped. The black plastic covers were tight at all 4 corners but the middle of the covers seemed to be bowed up. In an attempt to fix the carbs on a Sunday afternoon, I machined the covers flat again on the belt sander. The engine ran, but the idle screws did little to help the idle mixture. The engine idles at about 1000 rpm (on muffs) and the timing is at about 2* atdc. (should be at 1*btdc to 1* atdc) The engine will idle for a few seconds then backfire out of the carb and usually die. (mostly the top carb). While idling, the engine will sometimes start running on one cyl but it can be quickly corrected by choking one carb with fingers. (happens with iether carb and fuel can be seen dripping out of the front of both carbs durring idling) The carbs are actually condensating near the top covers when idling. Plugs are new. Comprression is 150 in both cyl.
Tried to order new carb covers but they are out of stock everywhere. All of the idle passages seem to center around the carbs top covers. Any one ever have issues with the carbs top covers?
I disassembled the carbs. They looked like new inside. I did not replace any of the gaskets, yet. I notced that the carb covers were warped. The black plastic covers were tight at all 4 corners but the middle of the covers seemed to be bowed up. In an attempt to fix the carbs on a Sunday afternoon, I machined the covers flat again on the belt sander. The engine ran, but the idle screws did little to help the idle mixture. The engine idles at about 1000 rpm (on muffs) and the timing is at about 2* atdc. (should be at 1*btdc to 1* atdc) The engine will idle for a few seconds then backfire out of the carb and usually die. (mostly the top carb). While idling, the engine will sometimes start running on one cyl but it can be quickly corrected by choking one carb with fingers. (happens with iether carb and fuel can be seen dripping out of the front of both carbs durring idling) The carbs are actually condensating near the top covers when idling. Plugs are new. Comprression is 150 in both cyl.
Tried to order new carb covers but they are out of stock everywhere. All of the idle passages seem to center around the carbs top covers. Any one ever have issues with the carbs top covers?