Onan 16 HELP

[Shuboxlover 478]

I bought a 416-8 last fall....long story short, I left the key on and fried the coil.  Bought a used coil from a member here, installed it last fall, got it running but was having some electrical issues I think.  I'd turn the key and it wouldn't turn over.  I don't think it was safety switches.  Anyway, I was going to try and track down the electrical issues today, put a battery in it...it turns over but no fire.  I pulled the plug to confirm...yep, no spark.  I measured the coil...primary ~3.9 Ohms.....secondary ~16.9kOhms.

 

I'm pretty certain the coil is o.k.  especially with those readings, and I had it running last fall with this coil.

 

Where do I begin to track down what my issue is?  If was a Kohler, I'd already be up and running, but haven't had to trouble shoot Onans very much.

 

Any held would be greatly appreciated,

 

Thanks

[the_nite_owl 15]

Check that the coil has 12v coming from the ignition switch and that the wire from the points is good.

Then check the points and condenser.

I had issues with all of these items when I swapped engines.

[Desko 608]

On the new onan there is no points check the ignition trigger and rotor behind the fly wheel and check your 9 pin connector, fuse block, and key switch

[Shuboxlover 478]

How do I test the trigger??

Rotor???

Do you have any specifics I should check on the 9 pin, or is a simple continuity check good enough....Just to make sure it's passing through the contacts..

[gwest_ca-(File Mod) 11,026]

Onan service manual

 

Garry

[Shuboxlover 478]

Thanks Garry!!!!!

[Martin 2,131]

Garry posted the manual. everything you need to diagnose the ignition section is in there. 

the 9 pin should be looked over for any burnt, loose, corroded contacts and burnt or loose plastic connector halves. they usually have problems at the high amperage circuits but any of the connectors can be corroded or not be passing juice correctly.

if a simple continuity check passes that would be ok. if they pass visual then just ohm each side of the connector and check.

Edited May 4, 2014 by Martin

[Shuboxlover 478]

I followed the directions in the service manual....started by hooking a wire from the positive battery terminal to the + side of the coil.  Fired right up....runs great after I unstuck the needle in the carb and adjusted the float.  Now I have some wire checking to do....at least I'm on the right track...Thanks guys!!!  I'll let you know what I find...OH....What would be easier, following the wiring diagram of the motor, or for the Wheel Horse?

Thanks Martin...I'll start with the 9 pin when I get home tonight after my sons baseball games.

Edited May 4, 2014 by Shuboxlover

[Martin 2,131]

there is two safety switches at the pto. look at the one with the yellow and orange wire hooked to it. the seat switch is also hooked into this circuit and one and/or both circuits need to be closed for 12 v to get to the coil through the yellow. if either is jumped look at the connections to see if they are indeed connected......

 

heres the circuit from the demystification manual......

 

 

could also be a loose connection or bad wire. check the whole circuit just to be sure. the fuse is in that as well and could also be a connection issue.....

Edited May 4, 2014 by Martin

[gwest_ca-(File Mod) 11,026]

Martin

 

This one is an Onan. Hard to keep track of them.

 

Garry

[Martin 2,131]

that is the only spark circuit in the 1992-1997 section of 416-8 and 416-H. its the same basic circuit to power the coil i would think.....

 

the 1990-1991 section shows it with the trigger.....

 

 

 

Edited May 4, 2014 by Martin

[gwest_ca-(File Mod) 11,026]

I don't know where they got the 1992-97 spark circuit. I saw the points and figured it was for a 1986 K-Series but they didn't use an ignition relay on them now that I check. 1987 used the M-16 so not correct for it either. I'll dig deeper on a clear day. It may make more sense.

 

Garry

[Shuboxlover 478]

O.K.....got that part figured out.  Turns out it was the ignition switch not passing the 12V to the coil.  Thanks for all the help.

 

NOW......while I mow with it, it surges some.  Mostly when I let the clutch out, or start to mow some taller grass.  It seems to like the throttle about 75% (that's my guess at what % it is)  Anything higher than that, is seems to surge worse.  Does this sound like I need to adjust the governor, or is it a carb issue.  The thing fires right up, and runs pretty good....other than the surging.

 

 

Ideas???

[Martin 2,131]

main jet (carb issue). take the top off the carb and clean out the bowl. while you are in there do the low speed jet as well as the main.

some info here....

 

[Shuboxlover 478]

Thanks Martin, I'll give that a whirl, hopefully tomorrow night.  I'll report back!

[gwest_ca-(File Mod) 11,026]

 

Garry

[shorts 182]

Just a tip on the Onan carbs, they are kind of fussy when they get dirty, after you take the top off and clean it, go back and clean it again before you put it back together

[Shuboxlover 478]

Just did all this and now it's worse than before....clean it again???

[Shuboxlover 478]

Of COURSE it will run like crap when you forget to put the idle jet back in.  

 

Anyway...It is still doing the surging thing.  It's weird...sometimes I'll be mowing for 4-5 minutes and it doesn't miss a beat, then all of a sudden it starts surging.  It almost seems like something needs to initiate the surging, either letting the clutch out, getting into some taller grass, going uphill with the PTO engaged.  I can go uphill all I want and it won't surge as long as I keep the deck disengaged, the minute I engage the PTO, surge!!!

 

It also did this thing a couple times where I was mowing right along, running great, then all of a sudden the engine speed went way up and then down and then ensues the surging.

 

I has fresh gas, new fuel filter, the air clearer isn't new, but it's not too bad.

 

NOW WHAT!!!???!!?!?!?!?

[shorts 182]

It's probably still the carb acting up, but just for grins look in the manual and double check the governor sensitivity adjustment settings and procedure, read the instructions completely and familiarize yourself with the procedure before you start adjusting things