As a reminder have an 861 that is coughing/belching through the carb when giving it gas from idle. Seems to run ok...but not as smooth as my jube.
1: Been through the carb several times to make sure there was no passage left closed. Rebuilt it cuz it was leaky
2: Cleaned distributor to make sure advance weights were free
3: Just in case there was too much play in the distributor bushings, installed an EI that I had on the shelf
4: Checked and rechecked timing. Found TDC by feeling for compression on #1...etc.
5: STILL belched and coughed when giving gas rapidly from idle. :?
6: GB in MT suggested a vacuum test. Vacuum had bouncing needle and low vacuum, which pointed to a timing or valve issue.
Today I decided to start over on the timing. When I was a kid we set timing without a timing light (couldn't afford one). So thought I would try that. I pulled the plug wires from the distributor cap so as not to be influenced by where they had been. Checked compression on #1. Without looking at the flywheel I hand cranked engine to just before compression on #1. Plug wires were put back in the cap. Guess what...fired right up and belch problem was GONE! Engine ran smooth, vacuum good, no vacuum needle bounce. Loosened distributor and advanced it, making sure there was no lag when starting. Redid the carb settings. Ran it up and down the road and it ran s m o o t h!
Out of curiosity I went back and checked the timing marks. It looks to me that I am now set on the one that is 180 degrees out from the one marked (0). There are no numbers, just a heavy horizontal line. 180 degrees around the flywheel there is a zero (0) and a heavy horizontal line 5 degrees before. Anyway, it was set up wrong when I bought it a couple of months ago. I'm guessing if they had it 180 degrees out they may have had it firing on something other than #1 first so it would run??? Not sure, but i think it is right now.
Also had a fluctuating oil pressure, between 20 and 40 lbs. SoundGuy suggested idle with ATF and Seafoam. On oil change found piece if gasket in oil pickup tube. Now 25 lbs idle, 40+ lbs at 1200 lbs!
Thanks for the help guys! Maybe I can move on to swapping the PS over from my 841D...
1: Been through the carb several times to make sure there was no passage left closed. Rebuilt it cuz it was leaky
2: Cleaned distributor to make sure advance weights were free
3: Just in case there was too much play in the distributor bushings, installed an EI that I had on the shelf
4: Checked and rechecked timing. Found TDC by feeling for compression on #1...etc.
5: STILL belched and coughed when giving gas rapidly from idle. :?
6: GB in MT suggested a vacuum test. Vacuum had bouncing needle and low vacuum, which pointed to a timing or valve issue.
Today I decided to start over on the timing. When I was a kid we set timing without a timing light (couldn't afford one). So thought I would try that. I pulled the plug wires from the distributor cap so as not to be influenced by where they had been. Checked compression on #1. Without looking at the flywheel I hand cranked engine to just before compression on #1. Plug wires were put back in the cap. Guess what...fired right up and belch problem was GONE! Engine ran smooth, vacuum good, no vacuum needle bounce. Loosened distributor and advanced it, making sure there was no lag when starting. Redid the carb settings. Ran it up and down the road and it ran s m o o t h!
Out of curiosity I went back and checked the timing marks. It looks to me that I am now set on the one that is 180 degrees out from the one marked (0). There are no numbers, just a heavy horizontal line. 180 degrees around the flywheel there is a zero (0) and a heavy horizontal line 5 degrees before. Anyway, it was set up wrong when I bought it a couple of months ago. I'm guessing if they had it 180 degrees out they may have had it firing on something other than #1 first so it would run??? Not sure, but i think it is right now.
Also had a fluctuating oil pressure, between 20 and 40 lbs. SoundGuy suggested idle with ATF and Seafoam. On oil change found piece if gasket in oil pickup tube. Now 25 lbs idle, 40+ lbs at 1200 lbs!
Thanks for the help guys! Maybe I can move on to swapping the PS over from my 841D...
