Follow up question on the backfiring issue I posted a couple weeks back. Learned a few good lessons from all this with regards to proper timing settings / curves etc. For the most part my motor is running a lot better but still... on occasion when I fire it up cold, has a tendency to backfire a bit. Timing is set at 38 degrees now with about 24-25 at idle (1500 rpm).
One area I am thinking may be an issue and wanted to run it by you guys.
When we first started the motor up after tear down if backfired bad due to having the distributor out of sync, so we replaced the power valves. What was in the carb was a 2.5 in the front and 3.5 in back. We went back with original (as shipped in the HP4150 - 950 cfm)) 6.5" valves. Since then I'm learning that my vacuum gage inside doesn't read accurately (actually have less than 5" at 1500 rpm instead of the 15 my gage was showing). I bought some new 2.5 and 3.5 valves and plan to put them in this week but do you think this would contribute to the backfiring?:confused:
One area I am thinking may be an issue and wanted to run it by you guys.
When we first started the motor up after tear down if backfired bad due to having the distributor out of sync, so we replaced the power valves. What was in the carb was a 2.5 in the front and 3.5 in back. We went back with original (as shipped in the HP4150 - 950 cfm)) 6.5" valves. Since then I'm learning that my vacuum gage inside doesn't read accurately (actually have less than 5" at 1500 rpm instead of the 15 my gage was showing). I bought some new 2.5 and 3.5 valves and plan to put them in this week but do you think this would contribute to the backfiring?:confused:
