[kilmer31]

Happy Halloween folks!

I just purchased a 91 or 92 420 with 1290 hours but not running. Previous owner said it died while mowing. I see no spark on left side, and have not checked other side as of yet. I will check key switch by checking 12v to pos side of coil first. Does this sound like the right way to go? Any help would be appreciated!

Thanks

 

[KB]

It sounds reasonable. I would check for spark on the other side also. If it is a 91 or 92 it has a p220 onan which doesn't use points. Check the wires that come up through the the engine tins, and their connections.

 

[vinnie110]

These engines have the spark plugs in series, lost spark system. Try and find the wiring diagram for your tractor, don't guess or you can wipe out some expensive parts.

 

[kilmer31]

Thanks guys. I am in the process of painting the master bedroom so you know how that goes!!!

 

[kilmer31]

Hello again. The model# is M00420X111917 Engine220G-I/11081C Serial#C923902923

I'm guessing its a 1991. I didn't state that it doesn't seem to be getting fuel as well. I have a couple of hours tonight to do some diagnostics. Any thoughts would be appreciated!

 

[kilmer31]

Update! No spark both sides. 0 fuel entering fuel filter. Both pistons moving.

 

[kilmer31]

Sorry guys. Anyone have the coil specs handy?

Thanks in advance!

 

[kilmer31]

If no points, then why a condenser?

 

[KB]

I would focus on fuel. Try a reserve tank feeding the fuel pump.

It possible that your not getting good ground testing for spark.

The condenser in this case keeps noise out of the rest of the system.

 

[KB]

Or just dump a tiny bit of fuel in the carb.

 

[kilmer31]

Thanks. Already put fuel in carb with 0 results. There is 0 spark. Not ready to replace coil as there could be other issues. I dont want to throw the bills out the window!!!

 

[volvo4fun]

Make sure the negative coil wire gets grounded through the points when you hand spin the engine.
Take the spark plugs out to make this a little bit easier.

Do you have 12V on the other side of the coil with the key in run?

 

[kilmer31]

Yes id do Robert. Thanks.

 

[kilmer31]

Found the fuel issue. Replaced line from engine to pump and oil sensor. Still no spark. Checked coil and seems to be out of speck.

 

[kilmer31]

Primary measures 3.3 ohms and the secondary 2130 ohms @ 64deg. Spec says 2.9-3.6 and 14500-19800 @
70deg. I know this is out of spec, but is it far enough to have zero spark?

 

[vinnie110]

Looking at your readings I would think you have about 90% of the secondary shorted out. So it is bad, can't make a good spark with 10% of the secondary.

 

[kilmer31]

Thanks for your input Vinnie. How critical is it that I make these readings at 70 deg.?
Should and can I still check the trigger and ring if the coil is bad? Also, I didn't mention that the vacuum line from the engine to the fuel pump was burnt up as well as the wire going to the oil pressure sending unit or switch. Im thinking the abundance of grass or a fuel leak caused a small fire which would have been right below the coil. Im guessing that could have fried the coil. Any thoughts on this? Nothing else looks burnt.

Thanks to all!

 

[boomers_influence]

lee
did you have your meter set on the 20K range?
do you have the original coil that
mounted with two bolts?
thank you boomer

 

[vinnie110]

Since the resistance of copper wire varies with temperature by specifying 70 deg they want you to measure the resistance of the coil at normal room temp and not with engine at operating temp.

Are you sure the wire and hose didn't get toasted from being too close to s hot surface

 

[gzec]

On more than one occasion I've had the wire break at the coil. It gets brittle after 30 yrs.