520 Won' Start

[WHX?? 48,839]

As mentioned in the snow movers thread shut her down to switch tractors and now won't start. Guess she didn't like my two timing! 

Initially thought no spark but there is. Two new plugs, NGK TR5, and new plug wires. Getting fuel (wet plugs) & 125 psi both jugs. She does pop once in awhile, backfire mostly. Ignition  timing seems to be off ?? but checks ok per the manual. 12 volts to the negative on the coil right when there should be ....see pic. Coil reads 3 ohms primary 17K secondary. Ther is a condenser on the positive side of the coil which sees 13 volts when key on but drops to 10.5 cranking. should I try disconnecting the condenser? Not quite sure what it's purpose is. Beginning to suspect to the trigger module but need some advice before I dig into it. and chance the timing gears jumped off?

[Achto 27,624]

11 hours ago, WHX24 said:

Beginning to suspect to the trigger module but need some advice before I dig into it. and chance the timing gears jumped off?

 

Have you tried giving it some sniffin' salts to see if it will fire? Don't over do it with the sniffin' salts, just wanna check to see if it is a fuel issue. I had an issue with my walk behind blower, ran for a bit, shut it off & it wouldn't restart. Dried the plug off twice with a torch then drained the fuel out of the bowl to check for water & let fresh fuel in. Fired right up and ran good.

Edited December 30, 2020 by Achto

[AMC RULES 37,132]

LOL!

Sniffin' salts!

Remember, this is Jim you're talking to!

[WHX?? 48,839]

You might be on to something ther Dan although salts just made her backfire a bit more and I didn' want to over juice it. This tank of gas was in it since last winter. Started right up and ran fine for at least 45 minutes 

[ZXT 2,401]

Sounds to me like it wanted a FEL or something for Christmas and you didn't get it for it!  That'll teach you to two-time it for sure!

 

I agree with Dan. Give it a shot of ether. Beyond that, the condenser would be my next suggestion. Not really sure what its purpose would be on electronic ignition other to cancel out "noise". 

[lynnmor 7,316]

Review the information that you probably read in this thread.  Pay attention to how the trigger module is tested.

[squonk 41,169]

Year old fuel. It ran on what was left that was still halfway decent. Now all that's left is the stinky crap. Fill it up with fresh and try it. I've seen it before!

 

And you probably got some glop in the carb bowl to boot.

Edited December 30, 2020 by squonk

[WHX?? 48,839]

I did Lynn and ther was also some tests that involved  simple light tester. Trouble is my tester light grew legs and walked .... suspicion my boy abscombed it. Off tomorrow to buy another! 

Did that too Mike ...fresh hi test but maybe should have purged the lines. 

[WHX?? 48,839]

Condenser is supposed to help the module last a bit longer .... absorbing coil spikes... makes sense. 

[squonk 41,169]

A full bowl of crap will not allow the new fuel in. See if you can drain it out

[WHX?? 48,839]

Gonna try that next Mike but wouldn't the sniffin salts or choke cleaner get it to fire for a couple of seconds? 

I shouda posted this in engines ...my bad .. mods move if desired. 

Edited December 30, 2020 by WHX24

[Mikey the Monkey 697]

@WHX24 use some of that NY Indian reservation gas i left there! It's ethanol free!

[WHX?? 48,839]

Lol that's long gone Mikey.... burned it up in the atv deer hunting....didn't want it to go bad then you use it next year and havta haul  your rear out the plow field! Still trying to figure out why a red can says diesel fuel on it! 

[Mikey the Monkey 697]

No idea who put that sticker on there... probably a Vikings fan

[WHX?? 48,839]

19 minutes ago, Mikey the Monkey said:

No idea who put that sticker on there... probably a Vikings fan

Hear that @squonk!?!?

Much as it breaks my heart will just havta move snow in the AM with the back up rig.... with the windshield wiper,  electric chute turner and elevator.  Check the fuel for water on the deuce.

[ericj 1,578]

the onan service manual tell you how to step by step trouble shoot just about everything but maybe stale rotten gas, didn't have much problems back then with gas as we do now lol

 

 

eric j

[Sparky-(Admin) 21,350]

  I suspect either old crappy gas or water in the fuel (or both). As you know water drops and gas floats so even with fresh gas dumped in the tank the water will still be at the bottom getting sucked thru the fuel lines first. Probably time to flush the fuel system and get into the carb as well. 

[WHX?? 48,839]

Agreed Mike.... One bad thing that throws a wrench in our plans in having dedicated tractors is the sno movers often sit for months with no love other than a battery tender. Even using hi test gas and a shot of stabil or seafoam. Drain the gas and run the bowl empty. Blow the fuel line out. May become a spring ritual in the sno tractors. That and a little more love when getting them out in the fall. 

The deuce has got a check valve in the fuel line and Denny has a electric pump on the one he built but even then you have to crank forever without sniffin salts to get them to fire up  after a weeks of non running. 

[WVHillbilly520H 10,373]

Have you checked to make sure the fuel pump is actually working ? , they tend to go out when you need it most and "freeze" up from snow ending up on them where they are located on the 520 i used to put water pipe insulation over mine when winter actually meant snow more than twice, and I don't use ether/starting fluid only carb/choke cleaner seems to start/run better in my experiences. 

[Handy Don 12,257]

1 hour ago, WHX24 said:

you have to crank forever

In the really cold weather I've wondered if the cold intake manifolds needed for the twin have an effect until they warm up. Carb to cylinder on a one-lunger is a lot shorter.

[WHX?? 48,839]

Guessing it is Jeffery ... strong essence & appearance of gas at the carb and will not run by hand feeding or sniffin salts. Going to check it tho when purging fuel lines. Bout time I changed fuel filter anyway since the cab is peeled back and add a check valve if I have one.  I think Dan might have nailed it... find out after work. 

 

Brings up a question if it is water/moisture does dumping in a bottle of heet help? 

[WVHillbilly520H 10,373]

9 minutes ago, WHX24 said:

Guessing it is Jeffery ... strong essence & appearance of gas at the carb and will not run by hand feeding or sniffin salts. Going to check it tho when purging fuel lines. Bout time I changed fuel filter anyway since the cab is peeled back and add a check valve if I have one.  I think Dan might have nailed it... find out after work. 

 

Brings up a question if it is water/moisture does dumping in a bottle of heet help? 

Sometimes the HEET helps, it might be that dang ignition module.

[WHX?? 48,839]

18 minutes ago, Handy Don said:

In the really cold weather I've wondered if the cold intake manifolds needed for the twin have an effect until they warm up. Carb to cylinder on a one-lunger is a lot shorter.

Not sure Don it seems even in the summer tho not as bad. These Onans it seems each has it's own identity, The deuce you only need to jog the choke once or twice to keep it running, on Denny you need to blip it five or six times to keep it running. Once warm all is good. 

[WHX?? 48,839]

The deuce LIVES....give ya three guesses as to what it was... 

1) Water in Fuel

2) Ignition coil

3) Letting smoke out of the module 

4) bad NIB plugs

5) Jim's a horse's petoot

6) I have no clue

Ok it's more than three so sue me.... give ya a couple of days to stew on the correct answer....

[AMC RULES 37,132]

Definitely PETOOT!

Get's my vote! 

Who cares as long as you got it done.

Good job Madge!