16hp Vanguard - AllisAGCO 1616H (~Simplicity) won't shut off; HELP

bsrosell · Jul 23, 2014

Hi,
I have a AgcoAllis 1616H (same as a Simplicity), 16hp twin-cylinder Briggs Vanguard engine. I noticed the engine was not shutting off immediately after turning off the key; took four or five seconds (later told by dealer this is probably because the carb has a solenoid and the GAS is shut off, so dies from lack of fuel and 'shuts off' after a few seconds). But getting ahead of myself.

I of course first bought and installed a new ignition switch. No change, still kept running. At this point, i also noticed that getting off the tractor seat or leaving the clutch/brake pedal engaged DID NOT SHUT OFF THE ENGINE if I got off the seat.. I thoroughly checked ALL connections and switches (under seat, clutch, ground cable...) and all had continuity and were 'good'. Besides, unexpectedly (and unexplainable to me), the safety system DOES work when trying to START the engine; you have to be sitting on the seat, clutch/brake depressed, hydro lever in neutral, and PTO off, or it won't start.
So, electrical connections are all good.
Called dealer again, service tech said 'must be the electronic module then"... (located under the dash by the steering wheel). I replaced this, and STILL no change.

Talked to a service tech at the local Simplicity dealer again, he said to ground out the stud on the engine where the blue w/ white stripe wire connects, and see if it kills the engine. Doing so made it stumble, but engine still keeps running. All he could think of that would be left is "the coils" on each side of the engine".

Key point: PTO safety system DOES work; so no danger of tipping on a hill and having blades turning!

Anyone had this problem? I hate to take half the engine apart (plus buy new 'coils', not sure what they are for this type of engine, I'm more of a car guy) unless I'm sure that is the problem. I'd like to get a bigger tractor (3 acre lawn, and this is only a 44" deck) and I have five kids who take turns mowing, so either way I want to fix this, can't sell it like this and I want it as safe as possible for my kids too obviously while we are still keeping it.
Any suggestions appreciated!
Thanks!
Thanks!!!

rankijr · Jul 23, 2014

I have that same engine (with electric start) on my lumber mill. When I shut off the key I don't think there is any delay. I'll check it out more thoroughly tomorrow to see if there is any delay.

bsrosell · Jul 24, 2014

Thanks; I've had this since it was almost new (since 1998), and it always shut off immediately as you'd expect. So, something has changed and is 'wrong'. Just a matter of what, and how to fix it..... I've eliminated the wiring and safety switches (99% sure), and replaced both the ignition switch AND the electronic control module, so don't know what could be left except something inside that engine shroud where the blue and white wire goes. The "coils" according to the service guy at the local Simplicity dealer. He didn't strike me as having come across this problem before though, so would be really nice to hear of someone who replaced these 'coils' and did indeed fix the problem.... And how easy or difficult a job it is to do. Lots of hours on this tractor, not sure how much more money I want to spend on it, or TIME.... but still runs good and mows good, and I was raised by parents who grew up in the Great Depression, so I'm morally obligated to run everything into the ground before replacing anything

rankijr said:
I have that same engine (with electric start) on my lumber mill. When I shut off the key I don't think there is any delay. I'll check it out more thoroughly tomorrow to see if there is any delay.

rankijr · Jul 26, 2014

I started the engine and let it warm up. I timed it from when I turned off the ignition switch until it had completely stopped. It was no more than 3 seconds (if that much). When I turn the key to the on position, I can hear a relay pickup. This relay controls the on/off function of the engine. If your engine has a similar relay, that may be the culprit.

bsrosell · Jul 27, 2014

thanks rankijr; I'll have to look (listen?) for that. I THINK that is the electronic module in my system, replacing any relays, but worth double-checking.

bsrosell · Dec 29, 2014

FIXED! Had (another) PTO-oil-seal leak to fix (ugh, scratched the crank journal pulling the old seal, hope the fine-sandpaper did the trick or more work next spring!) So, decided to hunt down that pesky electrical problem. Pulled the engine shrouds, and there it was, broken wire to ONE of the magneto coils. So, was not quite getting grounded out when key turned off, running on one cylinder yet (twin cylinder Briggs Vanguard).
Anyway, now works as it should, safety-wise. Wasted money on that new electrical console and a new switch, but oh well, still cheaper than having the dealer take it in ....!!!!!
Good old tractor yet, but with mowers moving out (four teenagers, and two started college this year), I'm thinking it is time to start looking for a nice big (54" deck?) John Deere X350 or something similar. What models of John Deere are the 'cheap' ones that don't use bearings and such? I heard they have introduced the cheaper versions into the market now too. Used to be you could count on Cub Cadet and John Deere tractors to ALL be solidly built with bearings all around, not bushings and nylon sleeves..... Sigh. A disposable world these days.

rankijr · Dec 31, 2014

Glad you got the problem fixed. Nothing worse than chasing electrical problems. In response to your question regarding JD models, I have a 100 series riding mower and I would say it is at the bottom end of JD products. It's an L140, 22hp, 48" deck. I bought it at Lowes about 6 years ago (JD only allows the box stores to sell the low end mowers). It's a sleeve and bushing machine. A friend of mine has an X series riding mower. It's built way better than my model but he also paid double what I did. Good luck with your search.