eavega
Lieutenant
- Joined
- Apr 29, 2008
- Messages
- 1,377
Hey folks.
I am doing my first carb rebuild on my 1976 70 HP Johnson, and I have a question. The phrase "link n synch" refers to linking and synchronizing the three carburetors so that they are all opening at the same time, as well as synchronizing the carburetors to the spark advance, right? If the spark advance mechanism have not been disturbed, then is there any need to adjust the timing on the engine? I checked the timing prior to removing the carburetors, and the timing was where it was supposed to be for this motor. I'm hoping that I don't need to mess with that at all...
A second question; when I disassembled the carbs I removed the high-speed orifice plugs with my own version of the orifice plug tool made per the specifications posted here on the iboats forum. The top and middle carb plug looked fine, but the bottom carb orifice plug was somewhat damaged. The slot in the top of the plug was broken off, like someone had used the wrong tool to either put it in or take it out at some point. Lucky for me there was enough of a piece of it that I was able to carefully back it out. Would this cause the number 3 cylinder to run badly? I ask because the reason I am rebuilding the carbs is that I have had the problem of this motor falling on its face when you try to throttle up, but only after it has been run then shut down for a bit. After checking spark and compression, I concluded it must be a fuel issue, and specifically in the high-speed passages of one of the carburetors.
Any opinions would be greatly appreciated.
Rgds
I am doing my first carb rebuild on my 1976 70 HP Johnson, and I have a question. The phrase "link n synch" refers to linking and synchronizing the three carburetors so that they are all opening at the same time, as well as synchronizing the carburetors to the spark advance, right? If the spark advance mechanism have not been disturbed, then is there any need to adjust the timing on the engine? I checked the timing prior to removing the carburetors, and the timing was where it was supposed to be for this motor. I'm hoping that I don't need to mess with that at all...
A second question; when I disassembled the carbs I removed the high-speed orifice plugs with my own version of the orifice plug tool made per the specifications posted here on the iboats forum. The top and middle carb plug looked fine, but the bottom carb orifice plug was somewhat damaged. The slot in the top of the plug was broken off, like someone had used the wrong tool to either put it in or take it out at some point. Lucky for me there was enough of a piece of it that I was able to carefully back it out. Would this cause the number 3 cylinder to run badly? I ask because the reason I am rebuilding the carbs is that I have had the problem of this motor falling on its face when you try to throttle up, but only after it has been run then shut down for a bit. After checking spark and compression, I concluded it must be a fuel issue, and specifically in the high-speed passages of one of the carburetors.
Any opinions would be greatly appreciated.
Rgds