1988 60hp sneeze video, please help!

[renegade15]

Here is a youtube link to a video I took of my motor idling and "sneezing"...as best I can describe it.

http://youtu.be/PGFyG9gIHTE

I know some of you have helped me with some other items along the way with this new to me motor, but here's another one!
So far new with the fuel delivery system, all hoses from tank to each individual carb, new racor 10 micron filter(with the clear bowl on the bottom), new primer bulb, carb rebuild kits and a good solvent soaking/cleaning, running off of an external tank now to rule out anything regarding the tank pickup/hoses. My fuel pump is the next thing I plan to replace. I took it to a mechanic for a diagnosis of barely running at all and he did a link-n-sync, timing adjust, and rebuilt the fuel pump. She ran great till this past weekend and then almost left us stranded. All of a sudden BAM! the idle picked up and she ran great after about 20 minutes of pumping the primer bulb to keep it idling, the primer bulb also firmed up. However this sneeze is something new...any suggestions greatly appreciated. The vro is blocked off and I'm running 50:1 premix.
Thanks in advance!

 

[Daviet]

Re: 1988 60hp sneeze video, please help!

When you overhauled the carbs did you remove the core plugs on top of the carb and clean the passages underneath? Are all of the idle orifices clean and the same size?

 

[renegade15]

Re: 1988 60hp sneeze video, please help!

Thanks, but I did this and so did the mechanic I took it to...supposedly. It does seem like a lean sneeze no? But I don't get why it ran great for a while and now it's running like garbage again. I don't think anything is getting past that 10-micron racor? Plus it has the clear bowl so I could see if there was a bunch of junk coming from my tank. Any other ideas?

 

[Daviet]

Re: 1988 60hp sneeze video, please help!

If you are sure your fuel system is ok, use a inductive timing light and check the spark on each cylinder and see if you can connect the miss with a cylinder.