Just the other day I had one of my regulars bring in a huge lawnmower for me to look at. It has a Caterpillar diesel engine on this huge grass cutting machine the likes of which I’ve never seen before. But as with anything mechanical/electrical if given the right tools and the proper information I’ll take on the challenge.
It wouldn’t start; the first thing I could tell about it was the starter bendix was out of it. It would hit the flywheel spin a quarter turn and then nothing. The bendix would stay engaged and the starter motor was spinning like mad but the bendix never moved. Each time I would turn the key the same thing would happen. The engine would spin just a bit and then the bendix would just stop turning. I took the starter off and gave him a call.
Since his place of business was just around the corner it didn’t take him long to show up. “I’ll go get it rebuilt,” he said, as he grabbed the starter and headed out the door.
A few hours later he was back, but the starter wasn’t repaired. He had taken it to two different starter overhaul shops and both said it was Ok… I thought that was a little strange… this thing was in dire need of a bendix. I muscled the engine over with a pry bar just to make sure there was no issues there, it was fine. I was very certain the bendix was at fault, there was no mistake about it. But, if the overhaul repair shops have as good a reputation for their work as I have, I’ll have to take another look at this whole thing and be sure I’m not diagnosing it wrong.
I stuck the starter back on and as I expected the same thing was happening to the starter.
I decided to skip this little problem and try to determine if anything else was wrong… because according to the owner the starter probably wasn’t the only problem wrong with it. He had already tried a new ignition switch but when that didn’t do the trick he brought it to me.
After checking the wiring diagram it was clear that one wire was on the wrong post on the replacement ignition switch. I asked the owner if he made sure he put the wires back correctly when he changed the switch, he not only was extremely sure that he had them in the same place, he also took a photo of the old switch wiring so that there was no mistake about where each of the wires went. With that information it had to mean only one thing… the ignition switch had to have been wired wrong from either a previous repair attempt or from the factory. Because, the way it was hooked up the starter solenoid was engaged the whole time the engine was running.
I went ahead and moved the wires to the right spots and gave it one more try. When, I could get the starter to stay engaged long enough to spin the engine, there still wasn’t any voltage at the fuel cutoff solenoid. Something else had to be wrong with it. Time to consult the wiring diagrams again. Now it was only a matter of following the road map of a wires and trace out how all the individual safety cutoff switches played a part in the starting and running of this beast. Sure enough, one of the fail safe switches was faulty.
It should start now, that is, if you could get the crazy starter to engage long enough to throw the engine over top dead and create enough compression to keep itself going. It took several attempts of flicking the key on and off to get it to happen but it did finally start. Once it started I knew why no one noticed the starter bendix was still stuck out against the flywheel… you couldn’t hear a thing with this huge motor blaring away (ear protection is in order) Now, the owner only had one more task to do. Take the starter back one more time to the rebuild shop and get a new bendix installed.
I offered to install a new bendix for him, but he insisted on going back to the overhaul shop and tell them about it. He said there was something about “putting a board in the bendix” which seemed to be the way both places checked to see if the bendix was any good. I’ll bet it would hold a board… but I don’t think a little old piece of wood jammed into the starter nose cone was any match for this big diesel motor.
I just hope my reputation has gotten to that end of the city, because he planned on telling them who said the bendix was bad. Even though the starter overhaul shop was convinced it wasn’t the bendix… he was going to insist on having one replaced.
A day later he had a new bendix and the big old grass munching beast was as good as new. Sometimes, all it takes is experience and a reputation to get your point across. Just make sure you can back it up with clear evidence and good diagnostic skills. It’s an excellent way of gaining a good reputation, even in the big city or the small world we live in…