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GregB

326431 16hp Magnetron issues

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GregB

I have a 326431 16 hp Briggs in a 3416H.

Will start on ether and run fine and smooth, but on just gas from carb will not start and floods.

Aftermarket  carb.

Was worse with original carb.

Never played with Magnatron ignitions.


Engine has had exposure to moisture from sitting out covered, at least since I have had it here.

Where do I start?

 

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Horvik

I have a few questions ...

1. Is a conversion to magnetron, or has it always been on it. ?

2. Did you check for spark and is it turning over well? You have to spin magnetron a bit faster than the points style to make decent spark.

3. Are you sure the choke is working okay? On mine if you don't choke it cold it won't start either.

4. Sure the coil is not inadvertently grounding out through the switch? I've seen this happen and blow the coil out.

Good Luck

 

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Brettw

Well, I'm thinking either is more combustible, used as a starter fluid when gasoline won't cut it, and known to be a bit more explosive.  Too much and it can do some damage.  So maybe the engine is simply low on compression and will run on either but not gasoline?  Just a theory.

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GregB

"

1. Is a conversion to magnetron, or has it always been on it. ? Factory, here is IPL Pic, my date code falls into this range

image.png.285eb9bbd39b25609af849d14c68d3b0.png

 

2. Did you check for spark and is it turning over well? You have to spin magnetron a bit faster than the points style to make decent spark.  It sparks using a after market spark gap tool.

3. Are you sure the choke is working okay? On mine if you don't choke it cold it won't start either. Choke works fine, manual lever style

4. Sure the coil is not inadvertently grounding out through the switch? I've seen this happen and blow the coil out. Has Spark

 

Just to clarify a bit,

If you crank engine with choke on it does not want to start on gas, it floods gas out the carb body.

If you crank engine with choke on , puff the starting fluid, it will start.

Then it runs fine on gas.  Up and down throttle, driveable and smooth running.

 

I have cleaned contacts on Starter Generator, battery connections are clean, behaves the same way when I have it on a starter booster/charger.

Today I am going to get a fresh plug, put more fresh gas in the tank.

I will check for wetness of the plug after I put the new one in the engine.

The repair manual is a little vague on checking spark on the Magnatron systems, do the same rules on spark "jump" distance apply as to a points system?

 

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PhanDad

Did you try the "hold the throttle plate closed manually" when trying to start?  Just read about this "trick" and haven't tried it myself, but others say it'll "fix" the hard starting with the upflow path of the old single cylinder Briggs.  If I works, then I'd suspect a choke plate issue.  

Since it seems to be gas vaporization issue, does the tank contain last summer's fuel?  I believe it's less volatile than winter blend and maybe contributing to the issue.  Or try a heat lamp on the carb area to warm it up to "summer" conditions.  We are experiencing winter like temperatures ATM.  

 

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GregB

Worked on it this afternoon.

Drained the fuel tank got this:

image.png.fc07070ce2f49ca82837066c170c87bc.png

Not good condensation water I think, not to mention the dirt.

 

Drained the carb bowl and got shiny flakes wah


Tried to pull this:

image.png.9df230ca766193903d9d58807c2044e2.png

Had to use vise grips to get it out of the body wah

Installed another after market carb,

New plug , new carb, new gas, it starts on gas now, but sputters some, a little hard to start, but not unstartable.

 

Decided the motor is a keeper, now to pull it and break the rest down.........

 

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Horvik

With that picture of the foreign particulate in the tank, it need to come off and cleaned thoroughly. the at least you may eliminate that variable.

Also , what type of fuel filter are you running? I once made the mistake of running a paper filter on that tractor and had similar problems with it acting up. Paper filter is good when used with a fuel pump, not good without one.  Change to those small screen filters and it took right off. Also check fuel hose make sure they flow good.

 

Hope this helps

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