Bad running 8n

[NCScott]

Hi guys

I have a front mount 8n with 12 v conversion. It has no power on high throttle and backfires. I"ve checked the archives and checked everything I could find. I"ve changed points, plugs ( gapped and rechecked) condenser, cap, rotor, coil, took carb off (twice) cleaned and rebuilt. Weights in dist are free. I"m at my wits end! Please help!

Thank you for any help!

Scott

 

[souNdguy]

if spark is good and you have set static timing.

next check for a lean situation.

some choke help power?

 

[NCScott]

No, choke doesn't change anything.

 

[Bruce (VA)]

Did you set the timing? Did you check the shaft for sideways movement?

 

[pconnie]

check plug wires. run it in the dark. see if fire is jumping across wires

 

[NCScott]

I set the timing with a jig I bought and still ran bad so tried to adjust it and didn't make any difference. The condenser wire had almost corroded off and changed it thought that was the problem. Is it likely the new one is bad too?

 

[Bruce (VA)]

I also asked you: " Did you check the shaft for sideways movement? "

Did you miss that question? If the shaft moves at all, you will have problems.

"...so tried to adjust it and didn't make any difference."

Tell us how you set the timing; if you fully advance or fully retard it, you will see a difference. So it occurs to me that you are doing it wrong.

" Is it likely the new one is bad too? "

Probably not. What do the points look like?
75 Tips

 

[NCScott]

Hi Bruce,

Shaft doesn't move side to side. When I set timing with the plate on the outside of the distributor, the points just start to open when the plate is almost all the down. I've had this tractor for at least 15 yrs and it's always been at about the mid point and ran fine. I moved the plate bact to about center ( where it's always been) and it made no difference in how the tractor runs. The points are new as well.
Thanks for the help!

 

[Bruce (VA)]

How old are the plug wires? Are they in the conduit?

 

[NCScott]

Not very old. 2 years. Yes in conduit. I checked the order as well. I can usually get it running good with some new points so this has me baffled

 

[Bruce (VA)]

So......

It starts fine, runs fine, but backfires & has no power & back fires at high throttle, correct?

And you removed the advance weights & checked them?

Have you replaced the screws holding the points? Make sure they are not too long & hanging up the weights.