1976 Thunderbolt 1150 Secondary Timing Problem

[boatkaput]

This motor will not top out at high end without cutting out. It has great compression on all 6 cyl. We replaced the carbs, switchbox, trigger, stator, rectifier, plugs, coil, and all wires. Fuel system and water pump works fine. The timing is dialed in. It starts with no problem. Someone mentioned the secondary timing needs to be adjusted but they don't have the equipment to do it. We are at wits end on this thing. Does anyone know what needs to be done with this motor aside from sinking it? Thank you for any help.

 

[kungpaoshizi]

Re: 1976 Thunderbolt 1150 Secondary Timing Problem

Idle mixture?

 

[Chris1956]

Re: 1976 Thunderbolt 1150 Secondary Timing Problem

Max Spark Advance is 21* BTDC. I doubt that is your issue, but check it. Remove spark plugs 2-6, install them into their wires and gound their bases. Not put timing light on top cylinder, remove prop advance throttle to max and crank motor by jumpering starter solenoid.

If that is not it, pump primer bulb at high speed and see if thta fixes it. If so, repair fuel pump.

 

[boatkaput]

Re: 1976 Thunderbolt 1150 Secondary Timing Problem

Max Spark Advance is 21* BTDC. I doubt that is your issue, but check it. Remove spark plugs 2-6, install them into their wires and gound their bases. Not put timing light on top cylinder, remove prop advance throttle to max and crank motor by jumpering starter solenoid.

If that is not it, pump primer bulb at high speed and see if thta fixes it. If so, repair fuel pump.

Thank you all for helping, I had someone look at it and they said it had to do with the tachometer not working and that is why it doesnt run properly. Does this make sense?

 

[Chris1956]

Re: 1976 Thunderbolt 1150 Secondary Timing Problem

Gee, I cannot think of a reason the tach would affect high speed operation. But for fun, disconnect the yellow stator wires from rectifier and tape them up to insulate. I would disconnect the red wire as well, and tape it up. Now retest.