Hi guys,
need some ideas here. I have a old Toro model 20672, serial run 300****, 21 inch rear bagger. In the beginning of last winter I did a normal layup for the mower. Drained the tank and ran it dry, changed the oil, put two drops of oil in with the new sparkplug, washed it etc. Same as I have done since I bought it new years ago.
In the beginning of this summer I started it up and it ran good.( I should note here that I have another toro mower that I use but is not as strong as this one.) I then again drained it and haven't used it all summer.
I tried to start it today and it won't start. The compression sounds good and it will, at times, start but stop quickly. I pulled the carb. and cleaned it (found some interesting gunk) and reassembed. It started misfired and stopped.
I have also taken off the top piece and wirebrush cleaned the magnets on the fly wheel and the ones fixed on the side and put on a new ground wire. Also inside the sparkplug lead so the connections are clean.
Fuel line seems clear as with it off the carb. gas will run free.... However, when I pump the primerbuld I do not hear the usual "whoosh" of fuel flow nor do I seem to have any of the normal resistance that you feel of fuel drawn by the primer action.
Still a exercise to pull the rope with negative results.
Any thoughts?

 

Take the bolt out that holds the carburetor bowl on and look closely at it. Near the end, in an unthreaded section, is one tiny hole that you may not be able to see if it's clogged. Find it and poke a wire from a breadbag twist tie through it. Then clear the other more obvious holes in the center and sides.

 

I knew I forgot something when I had the carb apart. Today I re-pulled the bolt but only found ONE hole below the threads. Cleaned the whole thing and couldn't find any more holes. Is it possible that this model has a bolt with only the one hole?
The trouble is still that it won't start. I tried to check the spark but pulling the cord and holding the plug is a feat in itself. Is there any other test for the coil besides holding the plug for spark? Starting to think that the coil went bad.
Is it possible to rig a jump start on this model with a battery? Far out, I realize, but they do have them now with electric starters. Just thought I would ask.

 

Try priming it through the plug hole with a teaspoon of gas. Then half choke, full throttle pull the rope.

 

It should have a tecumseh engine on it, and nearly all of them have the hole I described. Does the nut have a head, then an unthreaded section with the holes, then threads, then another unthreaded section at the end?

 

Pulled the bolt again. It is 1/2 " long and . It has threads at the end and then a unthreaded section then the head which has a "75" stamped on the bolthead.
It has only the one hole in the side that I found. I even went over it with a magnifying glass and didn't find any other holes. Right now with the bowl off, I drop the float and the gas runs.

Marbobj; tried that before and it didn't work.

 

Okay, that's a pretty old style. You may wind up having to remove the carb and soak it in carb cleaner to get it right.

 

........checked the bowl today and after priming I had gas draining when I loosened the bolt. So I "assume" gas is now getting there. I got one of those Harbor Freight spark plug testers and connected it. Appears to have no spark. As a test I put it on a known working mower and it lights up, so it works (for now).
I guess I have to face the fact that the coil is probably bad. I checked the magnets on the fly wheel and they still appear to be strong as they pull and hold a screwdriver.
Do you know, by chance, what the clearance should be for the coil and flywheel? Maybe that is off. What do you think?

As a added test I tried starting with the "kill wire" attached and detached.

 

Try testing it with the spark plug and have someone pull the rope while you watch for spark. If none, and the plug is grounded, then you may well have a bad coil. You said it would start, then stall, which is a classic clogged carburetor symptom, especially with a tecumseh, but yours may be ignition related. The gap on the coil should be close to .010-.014"

 

........Just thought I would give you a update since you helped me on this.
I redid the cut-off(grnd) wire, re-pulled the carb and recleaned. I then filled it with carb cleaner and reinstalled. Then I put it back in the shed and went on vacation for two weeks.
After returning, I waited another couple of days till we had nice weather and I felt ambitious again. Went out put fresh gas in this problem child, pulled/reattached the fuel hose to make sure it was clear and prepared for a afternoon of exercise. Pulled the cord and it started on the second pull!!!!!!!!
Blew alot of white smoke then settled down and now runs perfectly!!!!! Stopped it, waited a few minutes and it starts now on the first pull for seven times in a row!!!!!!!!!!!!!
Now that being said it probably will never start again!!!!

Thanks for you help.

 

Great! Thanks for the update!