Hi All , I am restoring a vintage Pioneer chain saw , spec’s call for setting points at 30 degrees BTDC , how do I determine that point? Should I assume the high point on the shaft would be used to set the points should be set.?
Geo🇺🇸
Unless the plate holding the points can be rotated with respect to the camshaft, the spark timing is fixed by gearing. Follow Cheese's response for setting point gap.
If there in no mark or tab on the engine indicating TDC and/or anything indicating degrees (e. g. 10°, 20°, 30°) before TDC then you'll need to pull the spark plug and start measuring.
When the piston is at its highest point in the cylinder, that is TDC (top dead center), and likewise when the piston is at its bottom most point, that is BDC (bottom dead center).
Referencing a circle that has 360 degrees, TDC will be at 0° and BDC will be at 180°. To locate 30° on the circle before TDC rotate the crankshaft to make the piston move to a point that is 30° before TDC.
Imagine the Degree Wheel (image below) attached to the engine's crankshaft that moves the piston. Just by imagination you should be able to get very close to the 30° BTDC location to set the points gap.
Don't make something simple difficult. Set it to the highest point on the lobe then set the gap on the points . I have been doing it that way for 65 years and have had no problems. Have a good one. Geo
Quick question. I have a Homelite 26b / UT09525 that refuses to start, and I diagnosed the problem as poor compression, a bit under 80 PSI. I found a new OEM short block for a very good price and plan to do the swap by this weekend, but wonder
1) about the included bag of parts. Here's a photo:
[img]https://cimg7.ibsrv.net/gimg/www.doityourselft.com-vbulletin/693x711/parts_3c9c8faeb23c5055d4f25599ed84e914f774a3c6.jpg[/img]
I am reasonably mechanically inclined and should be able to figure it out, but was curious if there's a diagram somewhere showing how it all fits together?
2) Particularly for the bearing components, should I be lubricating anything, and if so, with what?
Thanks much!Read More
I tried to fire up my trimmer and gas was coming out of the muffler. As I pulled and every other time the sting wouldn’t move. Pulled the carb. Cleaned it put it on. Cleaned the spark arrester. It fired up and ran for about 15 mins and died. Hasn’t fired since. I pulled the carb cleaned it again. Checked the spark arrester, good. Checked for spark, good. Checked my compression, it’s at 90. Seems low. Only thing I changed was the 2cycle oil. Black max full synthetic. Don’t know if compression loss is my issue. Carb diaphragm seems good. I’m at a loss. Please help.Read More