Pretty dang cool, Troy! Daddy Like
Part three of my continuing quest to whip my 149 S/N 2050047U464260 into shape for the mowing season.
I first addressed the oil usage by replacing the head gasket and the head (see more below, and previous posts). Second, I made sure that the carb was getting fuel by replacing the rusty gas tank and clogged filter (see previous posts). Third, made sure the power was being transmitted to the hydrostatic pump by repairing the pin/cup connection, at least temporarily (see previous posts).
Following up on the installation of the High Boss head, I currently have a mish-mash of tin almost covering the head.
I plan to leave the High Boss head installed for right now, and when the tractor is split for painting, "correct" it to original low boss head. Meanwhile I will search for the correct tin for both High Boss and low boss heads. The tin for the High Boss head will be installed immediately and the correct tin for the low boss head will be installed later, when the tractor is painted.
After installing the head, I realized that with the added compression (the head gasket was no longer leaking), I needed to address the carburetion-- it just didn't smell right. I can never tell if the carb is running rich (unless I see black smoke) or lean (unless liquid gas is spitting out the exhaust), but I can tell when it isn't right. But before I tried to tune the carb, I thought I had better make sure the timing was correct. Although the tractor has always run OK since I bought it two years ago, it had never started particularly well. I was never sure if I was going to get it to turn over before the battery died.
The set of points that came with the tractor had "crusted up" when I first got the tractor home. I had to pick the crud off to get the tractor moving again after it died on my front yard after unloading it. I also installed an automotive condensor to replace the one that was physically damaged (water had gotten into the end cap). The only other thing I've done to the ignition system is to add the spark plug wire available from Kirk Engines, and the Autolite plug that Charlie recommends on his site.
The points installed on the tractor looked like this:
Everything came out easily, I had replaced the cover gasket earlier, it remained attached to the block. I wish I had some good advice for setting the points, but the only thing I'll offer is bring several different flat-bladed screw drivers. Also, if you're going to tune a Cub Cadet, understand that it turns Counter-Clockwise (CCW) as seen from the front of the tractor (that's Anti-Clockwise for you Brits). If in doubt, crank it with plug wire removed to see which way everything turns: don't guess.
The new points and push-rod:
The goal is to make sure that the crank is at the timing mark when the points just start to open, as you turn the crank by hand in its normal rotation. I managed to set my points at a "fat" 0.025 inch gap. They actually start to break just a bit past the mark (advanced), so as everything breaks in, the spark ought to move closer to the mark (retarded).
I could not find either an "S" (for Spark?) or a "T" (for Top Dead Center?), instead, I found a spot on the flywheel that had been spray painted yellow and showed an arrow point, or "<," that appeared to be intended to line-up with a raised line "--" on the blower cover back plate (shown above). I have to agree with Harry Bursell, that it appears to me that the best way to tell if your timing is dead-nuts on is to break out the timing light, if for no other reason than to properly see the stinking marks! (The marks were neither in the range of my bifocals or my naked eye --very frustrating on a hot day in the sun.)
The old push rod measured 1.5469" the new one measured 1.5525" --about .005" wear. I didn't think this was very much wear, but recent posts from knowledgable authorities indicate that even wear of a few thousandth's is enough to throw the timing off.
Since I had it open, I used the Allen head screws (socket head cap screws) available from Kirk Engines. The Allen heads cut down on the fumbling with the slotted screws. The new points seemed smaller in diameter than the old ones.
Everything back together:
I'm happy to report that the engine started more easily than before, and it seemed to have a bit more power. In fact, after setting the idle mixture, it starts on the first crank! It never did this before. Moreover, it now "smells right." I still need to figure out how to set the main mixture screw (it's now at 2-1/4 turns) and make sure I'm making the proper MAX RPM unloaded and loaded.
Edit: After the new head & gasket were installed, the engine started back-firing through the exhaust, which promptly blew out the bottom of the muffler, see last picture. Just another item for the next order.
