Xtreme Mower Mayhem

Well, this sorta is a technical question- ive got a 20HP onan , turns over fine, but for the life of me i cant get any spark/get it to run at all- its the way i bot it, non running.

Any secrets to get it going? Or any mod tips to get it running ( like aftermarket parts, ect to get it sparking) - its a wiring nitemare.

I need to send the info to my dad- he has a onan dealer sorta close that he could get me some schematics/info on it to get this beast running- itd either go back on the GT6000 or maybe go on my wheelhorse/MTD frankenstien's creation.

Thanks in advance.

un plug the kill wire going to the key switch. make sure you have about .010 clearance on the coil to the fly wheel. crank it. if you still dont have spark, then you need a new coil. if you get spark put the kill wire back on. most mowers have kill switchs on the seat and pto that will cause them not to fire. shoot some wd40 on them , it should help

Hmm- ill haveta look at it again- i forgot to mention its a horizontal 20HP twin cylender- i dont recall seeing a magneto setup.

I should pull the flywheel- Since its a 90's tractor it shouldnt have points- it does have a 2 post coil pack tho- the sensor is most likely under the flywheel.

Im almost wondering if i can use two coils or something like that - the wiring on the tractor is pretty bad- looks like the PO hacked it all up and some is missing- not to mention its sat outside in the rain for who knows how long.

Onan's are a different motor to me- the rest of my fleet uses briggs motors.

I almost considered seeing if the local tractor repair place around the corner would swap me a 18-20HP twin horizontal briggs/honda for it.

i took the motor off the chassis, and put the chassis outside- the motor is still in my shed.

The real pisser is the tractor is a high dollar for its day type- has the electric lift deck.

The funny thing is its twin- a 86 GTII with a 18HP twin briggs was in tons worse shape ( severely rusty) then the GT6000 - and i got that running and mowing first.

holly shit! I see what you mean by not being able to find the wiring diagram. I did a search and could not find crap. if you have the tractor model number you might be able to find it on searsparts.com. you might be able to use a 9volt battery on the primary side of the coils and check for spark when you pull the battery off. sounds to me like you have a bad pickup or hacked up wires. (you knew that already) if you were close you could bring it out. i like a good challenge

Yeah i looked on sears and the diagram looked like a kids crayon drawing- wasnt detailed at all.

Im thinking i might see what a couple automotive coils cost and use them( if the original is fried) - ill still haveta pull the flywheel n see whats under there.

Thanks for looking.

Another plus to going to thrift stores- i picked up a set of 4 brand new spark plug wires for $2 - also picked up a set of front brake pads for $6 - i plan on using the wire on the onan, the brake pads im going to cut and use for blade brakes on my tractors that need em.

You couldnt get either at an auto parts store for that price.

Here's a cheap shot at helping; You know Briggs engines, why not try to replicate that wiring harness, and temporarily swap coils, plug wires etc, on to the Onan. I'd replace one item at a time, until you get some action or a good result. Don't forget to use fresh fuel and a good battery. Good Luck & keep us posted!

Theyre two different animals- the onan must get its signal from under the flywheel- theres no magneto pointing at it.

Ill haveta get a owners manual or wiring diagram for it- then figure it out-  if i have to ill look into a couple old coil packs ( junkyard) and see what happens- if the coil is bad.

I have a 18 hp onan motor that i drag race. I had the same problem with the wiring we ended up rewiring the hole thing. the problem still wasnt fixed what we figured out is that u couldnt turn the key all the way. just turned it until it would turned it over. we would not have any spark either until then.

 The wiring was all messed up by the PO- they  didnt have a clue how to work on tractors - i need to start from scratch and redo all the wiring.

I too have a gt6000 with a 20hp onan. CAN'T GET A SPARK!! HELP!!!!!  I'm tired of playing the parts replacement game. Have replaced coil, plugs, switch.

http://www.lawnmower-parts.com/expert.php

Write to these guys, they seem to have all kinds of wiring and belt diagrams! 

I  finally got a wiring diagram for it- just need to wait till i either have spare time or the heat lets up( its still in the 90s here).... its not a priority project actually.

Y can download owners manuals for free  here:  www.sears.com/homeservices - look for the tractor section - put in your model number and can d/l a free manual - theres a wiring diagram in it.