DougC 2,641 #1 Posted November 16, 2015 Getting ready to start checking out some problems on the 1988 520H I got a short while back and wondered if you guys had any tips on a tach not working. The fuel and volt gauges work and so does the hour meter. Just wondered if there is any common problems I should investigate first. Share this post Link to post Share on other sites
gwest_ca-(File Mod) 10,516 #2 Posted November 17, 2015 Here is one page you can download on the tachometer from the Demystification Guidehttp://www.wheelhorseforum.com/files/file/5214-gauge-tachometer-113467-113476-78-0060pdf/Garry 2 Share this post Link to post Share on other sites
bubbacola 8 #3 Posted November 22, 2015 check the vacuum line to tachometer switch Share this post Link to post Share on other sites
cleat 4,996 #4 Posted November 22, 2015 No vacuum, just ignition power, ground, and AC signal from the charge coil. Check all 3 connections on the gauge itself and the connection at the voltage regulator. Also the 9 pin engine connector may be bad as well. Cleat 1 Share this post Link to post Share on other sites
bubbacola 8 #5 Posted November 23, 2015 dont know anything about the 520H . i bought a tiller and had to take tractor with it. It ran okay but a lot of missing bolts that i replaced... moving on there was a vacuum hose hanging by fuel pump i looked for a place for it to go. Not finding anything i got on wheel horse junkies with pic of hose... had a few guys say check this and that and one said its the vacuum hose for tach switch... left side near bottom of battery was a switch with two wires on it on the back side you could see where the nipple broke off. I did not repair but I held hose on back where it broke off and the tach did work but jumped alot..im sure if i replace that switch the tach would have work. I dont know the year the tractor. sorry for long story Share this post Link to post Share on other sites
cleat 4,996 #6 Posted November 23, 2015 That sensor is for the "air filter" light on the dash. If the air filter gets too restrictive a vacuum forms between the filter and carburetor which that sensor with the broken nipple can detect and turn on the light. Cleat 2 Share this post Link to post Share on other sites
Save Old Iron 1,563 #7 Posted November 26, 2015 make certain the tachometer signal lead (grey, I believe) is on the left most AC terminal when the regulator is orientated as shown in the diagram below. NO SIGNAL will be received by the tach if the regulator connector is flipped over. The charge system will still function with the connector flipped but the tach will not. 4 Share this post Link to post Share on other sites
cleat 4,996 #8 Posted November 26, 2015 Yes, one of the AC terminals is actually connected directly to the DC output internally so the tach would just see DC on that terminal I had a tractor that came wired wrong but as said by Save old iron, just switch to the other side. 2 Share this post Link to post Share on other sites
woodchuckfarmer 333 #9 Posted November 27, 2015 My gray wire came out of the 9 pin block , it was corroded . 3 Share this post Link to post Share on other sites
Save Old Iron 1,563 #10 Posted November 27, 2015 2 hours ago, woodchuckfarmer said: My gray wire came out of the 9 pin block , it was corroded . ahhhh yes, the 9 pin connector the gift that keeps on giving ! 1 Share this post Link to post Share on other sites
DougC 2,641 #11 Posted December 6, 2015 Well guys. Thanks to ALL your help I got the tach working today. The previous owner or owners had done some wiring alterations (butchering) and used house hold wire nuts and about an entire roll of black 14 gauge wire on multiple circuits. No AC voltage to tach terminal S from regulator. A jumper wire from the far left AC terminal to the gray wire tach terminal and the tachometer sprang to life and worked perfectly at different throttle positions. I will make a permanent wiring repair after I install the new voltage regulator I have coming from amazon to repair a different problem with the charging system. THAT TACH NOT WORKING WAS DRIVING ME NUTS........ Share this post Link to post Share on other sites
Kurt-NEPA 755 #12 Posted December 7, 2015 Thanks for the diagram Save Old Iron. The tach on my 88 520H is not working either. The diagram will really help in the diagnosis. Share this post Link to post Share on other sites
Tuneup 1,416 #13 Posted December 30, 2015 As you've found, DougC, that wiring mess is hiding other issues. Mine had the redneck treatment as well. Good luck! Share this post Link to post Share on other sites
