I have been running my 446 with B43 to check it out after finally fully assembling the tractor with air cleaner, all heat shields etc. On the first test things ran fine for 5 minutes or so then started acting like it was starved for fuel and then finally stalled. I couldnít restart it, not even a solenoid click. It might have just been neutral or PTO switch related....
Later I was able to start it again and did not get any of the same symptoms. Ran it for 10 minutes or so then put it back in the garage. When throttling down I got an exhaust backfire. I let it idle for another 20 seconds or so then shut it off. After a couple seconds I got another exhaust backfire. I wondered if I might be running too rich now that the air cleaner is in place.
After reading through posts here it sounded more like a valve or points timing issue. Incidentally I heard a ticking sound so had wanted to reinspect valve adjustments anyway. I have taken things apart to double check the valve adjustment and points timing.
Exhaust valve on cylinder 2 was a bit loose so closed the gap a bit to make it a snug 0.13.
Points gap seems to be .021 at widest. When checking the points gap I realized that I have never actually inspected the points on this engine. I havenít looked that many points ignitions so donít have a good reference to go on. I see some pitting, but am unsure if these are still workable. What do you think? Should I keep running with these as-is?
I am by no means, any kind of ignition expert but if those points were mine, I be filing on them.
There are special tools for it and I have them but in a pinch, I've also just used and emery board (nail file). Could also take a piece of 220 or so grit sand paper (for metal), fold it and drag it through several times and see what happens.
I believe others have mentioned that on Onans, the condenser's purpose is to stop the points from sparking but don't take my word for it.
Just drag 220 or finer emory or wet/dry paper through then to take off the high points. Then drag a piece of plain paper through to clean any grit out of them. Should get a few years more life out of them. I'd check the condensor while you are there to see if it is still within specs.
I cleaned the points up and made the final adjustment gap using the continuity method. It was breaking past 21 degrees and closer to TDC. After adjustment it breaks as close to 21 degrees as I could get it. On one revolution it breaks at 21 and on the subsequent revolution it seems to break a bit past 21. Maybe this indicates that something is worn? Anyways I decided to give it a try. I also replaced the - wire from coil to points as the old wire was crusty.
Things seem good after putting it back together. No more backfire and engine also seems to be cooler.
The only thing still concerning me is what sounds like valve ticking on the cylinder 2 side. Valves are adjusted to spec. I think Iíll just run it for a while to see how it goes.
After some hours Iíll check points again per Boomer to check for metal transfer. If there is transfer then Iíll replace the condenser.