I have a 1995 Mercury 75 hp outboard serial number 0G255313. It backfires out the exhaust at idle. I think the timing is off. I found a service manual online, but the settings don't seem right. It says they should be 20 BTDC max and 2 ATDC-6BTDC idle. When I check mine with the timing light at cranking the max setting was around 28 BTDC. I am a pretty good amateur mechanic with cars and small engines and I feel confident I can get this set, I just need to know that I am using the correct numbers and manual. Any help would be greatly appreciated!
More Information: It will idle fine with the hose on it in the driveway. Can't get it to backfire at idle. If I rev it with the cold start to about 3000 rpm I can get it to backfire. The previous owner has a clear filter installed between the built in tank and the primer bulb. That filter is not always full of fuel. I prime it and get it to fill but it will be empty sometimes when I check it. The backfire usually has a puff of smoke with it out the prop. I ran this boat on a river one time when I first got it last year and pulled a tube with my kids. Since then I have only ran it on an idle only lake fishing, about 3-4 times. When I pulled the tube on the river it would backfire at idle but seemed to run fine at 25-30 mph.
One more thing I forgot to mention. When I rev it with the cold start while running on the hose I rev it to about 3000 rpm and then push the cold start down and the POP happens as the rpms are dropping.
More Information: It will idle fine with the hose on it in the driveway. Can't get it to backfire at idle. If I rev it with the cold start to about 3000 rpm I can get it to backfire. The previous owner has a clear filter installed between the built in tank and the primer bulb. That filter is not always full of fuel. I prime it and get it to fill but it will be empty sometimes when I check it. The backfire usually has a puff of smoke with it out the prop. I ran this boat on a river one time when I first got it last year and pulled a tube with my kids. Since then I have only ran it on an idle only lake fishing, about 3-4 times. When I pulled the tube on the river it would backfire at idle but seemed to run fine at 25-30 mph.
One more thing I forgot to mention. When I rev it with the cold start while running on the hose I rev it to about 3000 rpm and then push the cold start down and the POP happens as the rpms are dropping.
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