John Deere Sabre mower 10 years old, trouble starting..?

Question

I have a 10 year old John Deere sabre mower, once you get it started up it runs and mowes perfect no engine knock, no grinding noises it still runs as a brand new engine. It is an 18 HP engine with 2 spark plugs. Not sure the EXACT type because im not that mechanicly inclined. We have so many small engine repair scammers around us that have took mowers from us saying they are un-repairable junk. So I bought a master lawn mower repair book and will tackle this problem myself since nobody will fix this for us. The problem is, you have to turn the key a couple of time and kind of jerk it for the mower to start. The starter engages and everything properly but it feels as if the gears are stuck that makes the flywheel spin and after a few times of the starter jerking at the flywheel it suddenly spins fine and starts up. What could cause something like this? The explanation the small engine scammers have gave us didn't make any sense at all, they said metal chips inside the engine are breaking off and thats why its hard to start and it will cost over 1,000 dollars to fix. I think this is complete bull, why I think that is because they have said my grandfathers old mower was unrepairable and it would be over 600 to fix and they'd like to keep it and scrap it. To make a long story short I said no give it back, cleaned the carb and it ran fine until this day and is still running strong. To get back on this problem, I would greatly appreciate any answers that may help, if you guys have any idea of what could be causing this before I tear the whole engine apart looking for a problem.

Thank you soo much.

-John

Answer 1

First you need to make sure that all the electrical connections are clean and tight. Make sure that the ground cable from the battery to the mower frame is clean and tight. Remove the big wire from the starter and with the key in the start position, check the voltage. It should be a steady 12 volts, if not you may have a bad solenoid. The gear on the top of the starter can be replaced if worn. The starter can be taken apart and cleaned, although getting the brushes back in is tricky sometimes. The other thing that come to mind is that on briggs engines as an example, they use a compression release system that works with the camshaft to relieve compression when cranking, if the valves are too loose this will not work and it makes it hard for the starter to spin the engine. If your engine uses a compression release system take a look at the valve clearances.

Answer 2

The first thing you should do is check, or bypass, that key switch. Intermittent contact inside the switch will cause the the starter to start on and off as you describe.

Answer 3

check all terminals for filth, build up of dirt etc...that will make current"flicker" sometimes

could be moisture or dirt in the key switch itself