Tue Mar 12, 2013 6:19 pm
My Cub has been running good since I did a valve job a little over a year ago. The Cub seems to have lost some of it's power so I pull the Cub into the shop yesterday and pulled the oil plug's and let it drain last night. So I went back in today to put the oil in and decided to check the timeing with a light. It was a little before the first notch so I put it dead on TDC and them pull the throttle up and it advanced a little over half way to the second notch. Is this where it is suppose to stop or should it make it to the second mark. Is 16 degrees the second mark? I will be checking the valves tomorrow. Thanks
Tue Mar 12, 2013 6:38 pm
It should advance to the second notch.
How is the RPM at full throttle?
Tue Mar 12, 2013 7:24 pm
Weights may be sticking in the distributor. Or it was running to fast when you set it to 0 at idle
Tue Mar 12, 2013 7:28 pm
Static time the engine - zero rpms. Start engine and full throttle, 1600 rpms or more. 2nd mark (16 degrees advance) and pointer should come close to lining up. Below 400 rpms the 1st mark should line up with the pointer.
Wed Mar 13, 2013 11:47 am
Eugene wrote:1600 rpms or more. 2nd mark (16 degrees advance) and pointer should come close to lining up. Below 400 rpms the 1st mark should line up with the pointer.
If you can't get both of them to line up, go with the TDC mark at the low revs. I had that problem and advanced it so the timing was correct at high idle and started having starting problems. Reset the timing to TDC static, and starting problems disappeared.
Wed Mar 13, 2013 5:56 pm
Well I got back in the shop today and finished work on my Cub. I started by checking the valves, hadn't checked them since valve job, everything was ok, a snug .015. Then I took the distributor off and checked the auto advance and the little weights where a little loose, so I tighten them up by tweaking the curves in the springs a little at a time. It took about three tries on each end to get them where it seemed to be good. I put everything back together and she wanted to start a little slow but did start. I set the timeing on TDC (at about 400) and them revved the engine up and it went to full advanced just like it should. Thanks for all the help guys!!!
Hope to plant cabbage this weekend if it drys enough!
Thu Mar 14, 2013 6:35 am
You did exactly what I do to correct distributor advance issues. Over time, the springs weaken and become slightly extended. This causes the timing to slightly advance at very low engine speed, even when cranking with the starter. One then sets the timing to TDC at idle, but the distributor is already partially advanced and has little more advance to add when engine speed is increased. There should be a small amount of tension on the springs when in the static (fully retarded) condition.
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