What am I missing?

[Tom Bond]

Took my 961 out for a ride tonight and noticed what I think is a definite miss in 5th. gear at about 1700 rpm. Pulled it back in and started pulling the plug wires one at a time off the distributor cap. Cylinders 2,4 and 3 a big difference when removed. #1 no difference at all. OK, I figure bad wire or plug. I swapped the # 1 wire with # 2 and still no difference at idle when #1 removed. OK, bad plug. I put in a new plug and same deal. So I remove the plug and ground it. Firing fine. Also might mention, I have strong blue spark on all 4 from cap. Only thing I noticed is it seems like the # 1 plug is dry as a bone and still sandblaster clean like it's not even firing. Almost like there's no fuel getting to that cylinder. Is that even possible? Like I mentioned, the plug is firing when removed and grounded. Just no difference in running at idle when I isolate that #1 cylinder. Timing is set at 5 degrees. Any ideas?
Thanks!

 

[Royse]

Seems feasible if there's no fuel getting to that cylinder to burn.
I'm not sure why that would only be noticeable in 5th gear at
1700 RPMs though. That part seems odd to me.

 

[Tom Bond]

Yes. Not sure. This one has me scratching my head. Purrs like a kitten at idle and up to about 1200 rpm then seems like it stuttering higher than that.

 

[DaveBN]

Sounds like you have a valve sticking open thus no intake suction on
that cylender.
Dave

 

[Tom Bond]

Sounds possible Dave. Thanks! What do you think about a teaspoon of fuel into the cylinder thru the spark plug hole just to get it to fire and possibly free up a stuck valve if that may be the problem?

 

[old]

Check compression on that cylinder. Could be a valve of head gasket problem

 

[showcrop]

I agree with the young fella about checking compression.

 

[Vito]

Does your distributor cap have a crack in it? Had a JD 60 that ran
good in the low gears but in the top gear fell flat on its face. This was
the problem.

Vito