It is a keyed machine. Will try your recommendations. Thanks.If it is a ”keyed” machine, try changing out the ignition switch. I’ve had to change out a lot of these over the years.
Also, trace the ignition wire. If there is a loose connection or a short you will get this problem. Make sure to clean all the ground points.
What copper contacts are you referring to? Sounds more like a starter solenoid issue than a starter motor issue. However, OP already changed the starter motor and just about everything else in the starter circuit.I agree that this sounds like a starter issue. The Denso starter in my old Thomas T133, w/Kubota V1902, did this for about a year before I fixed it. If yours is a Denso starter, the contacts wear down and do not make good contact every time your turn the key. Sometimes it's good to to engage, sometimes not. The good news is that the copper contacts are dirt cheap (on eBay), and it's a simple rebuild. Or you can replace the starter. If you can get it to engage after a hammer tap or two, pretty sure sign that's what its is.
Thank youIt has been mentioned but too often Grounds are the issue in a no start...(key, cables, solenoid, relay, etc) but the main ground cable AND the STARTER need good clean contact grounds to function properly....even though the starter was changed, (should have done a bench test before) if you didn't clean the block area that the starter fastens too it may be lacking a proper ground. As to contacts burned that usually happens when you insist on continueing to try to start the engine with a battery that is too low to both flip engine over and power up the ignition. So the low amps turn the contacts into an arc welder, pitting and adding carbon trails till it fails to function at all. Starter out or in the frame and bench test that it works...then back trail the wire till the culprit is found in my case its some where between the starter and the key and i cant find it.....so i put in a separate wire and switch with fuse and can use that to start till it shows up.
Thank youI should have been clearer in my comment that I meant the starter solenoid contacts. This would be the two plates that contact the plunger when the solenoid is energized. Rebuild kits usually include the plates and plunger, but it may only be the contacts that are worn and pitted, leading to an intermittent connection, or eventually no connection at all.
I missed that OP changed the starter. If he changed the starter (with solenoid), than this is probably not the issue.
ThanksUse a voltmeter, negative lead directly at battery ground connection, positive lead at starter positive terminal and observe voltage while click is occurring. it should be very close to batt voltage while holding key in start position. If ok install meter positive lead on starter case leaving negative lead at Batt negative post. Voltage should remain near zero when click is occurring{crank attempt}. If both are ok, it is a starter issue, if one is off it will guide you to which side of the circuit needs further diagnosis.
ThanksWhat copper contacts are you referring to? Sounds more like a starter solenoid issue than a starter motor issue. However, OP already changed the starter motor and just about everything else in the starter circuit.
I'd be tempted to connect a battery jumper cable to the +12v side of the battery and then touch the other end to the starter motor 12v lug (not the 12v lug on the solenoid but the +12v lug on the starter motor itself). If the starter motor turns the engine over with 12v directly connected, then I'd connect the jumper cable to the 12v lug to the solenoid and try the key to crank. If the starter motor still won't engage, but the click of the solenoid is heard, it's likely the starter solenoid that has failed.