Join Date: Mar 2009
Location: Fort Worth, Texas
Running way to rich - need ideas
I just put a new engine in my 95 vn and got it running but it's running way to rich so much so that sitting at 1-2k you can hear it loading up and it will finally die. Restarting is almost impossible. I've been into the carbs 3 times now checking everything and don't find anything unusual. Here is what I do know:
The engine is a from a 96 VN 750 and has 6,200 miles on it. It has a lot of vacuum at crank and idle. I have a Carbtune and it will pull the rods up far enought to click on the top of the gauge. My other engine would barely move them at idle. I don't know if that's an issue but it is different. I'm using the same carbs from the old engine where they were running fine. I have black smoke and the plugs are black indicating rich. The front cylinder is popping back through the intake and out the exhaust. I get a lot of backfiring from the front cylinder. It might be sticking valves because it's sat for so long. I had the same issue with sticking valves on the original engine and it cleared up after a few hundred miles.
When it loads up to the point of stalling I can see fuel on the pivot rods for the butterfly valve on the outside of the carb. As I said I've had them off 3 times now and gone through them. All passages are clear and all moving parts move freely. I'm going to check the float level tomorrow but I'm out of ideas. It seems to run fine once I get it out of the 3000k rpm range but as soon as I go below that it starts messing up. the idle mixture screw is 3.5 turns out and the choke is OFF. I have had the idle mixture screw out 2, 2.5, 3, 3.5, and 4 turns out at different times, there doesn't seem to be much difference after 2 turns. I don't think there is a way to set the ignition timing on these things. If anyone has any ideas where to go I would sure appreciate it.
Last edited by AceMcgyver; 08-05-2009 at 12:48 AM.