BCM Community

I have an 8v71-non turbo in an MCI 5b. My engine was removed and is not in the bus at this time.due to some very bad advise from a mechanic that was not familiar with two cycle Detroit's. The engine is in its cradle ,sitting on blocks at back of bus. The cradle is temporarily connected to bus frame so it cannot move around. The thermostat es are removed, starter and flywheel installed. Temporary fuel lines run from engine to fuel lines in engine compartment.Hoses run from engine to a forty five gallon barrel of water. Engine will run on floor were it is easy to get at. This engine is not going back in until everything is working proper.I found and installed a set of Jake brakes. While trying to sort out buffer screw setting, Jake shut down switch,and high idle air cylinder, I nearly had a runaway. When I removed the plywood from the top of blower from choking engine I noticed a oil film on rotors. Time for blower rebuild. New bearings,seals, and rotor seal rings and blower drive shim pack. Blower was re timed as per Detroit manual. My engine hunts when at an idle. Seeing that Governor is off check for worn parts. I had changed the fuel rods and pins at rack end a while ago and this helped helped will some of the hunting at an idle. I removed the weights in Governor . I can't seem to make weights stick or bind when moved back and forth when held in hand. I notice a small wear mark on arm of high speed weight were it contacts Governor riser. Is it possible that this small flat spot is causing some of my hunting??I can't seem to find any wear in arms, pins yokes,bearings.,or other moving parts. I am open to all suggestions on were to look. Thank Larry  I have other questions like fuel pressure and other possible transmission combinations that I would like to ask later . Am I better to keep adding to this (ina few days when I get to that) or am I better to start a new topic each time?   

My small experience suggests that hunting idle means the idle speed is too low, and the buffer setting is wrong.  I had that when I had my idle set to around 500 rpm, raising it to 600 reduced the hunting a lot, and adjusting the buffer screw so that it raised the idle speed slightly - around 15 rpm - smoothed the idle right out.  This assuming the rest of your tuneup is correct.

Brian

separate post:  that way each issue can be addressed.  also ck search feature at top.   Please update your general location and bus type. Lots of members will not respond to a unknown busnut. Could be your answers a few miles down road. We know bus type by post so why not put it in you profile or signature.    Bob