420 ignition timing

[kdl]

Converted 420 to electronic ignition ( giving it to my grandson so I did this to make it less maintenance for him ) I'm timing a 420 with a advance timing light. I set the base timing with engine at idle ( no distributor mechanical advance ) set to tdc mark on flywheel . then at full throttle ( with distributor mechanical advance ) I have 15 degrees of advance . Does this sound good to you ?

 

[M-MAN]

It's supposed to be set at full throttle. You want SPARK centered in the timing window. IF everything is perfect you will see DC/TDC somewhere in the window at low idle. Full throttle is the important one and idle just shows the condition of your distributor, cam, and gears.

I don't remember what the timing advance actually is.

 

[John T]

Sorry I do not have the 420 timing specs, maybe some kind gent who finds them can post it ??? Just winging it 15 BTDC AT FULL RPM ??? sounds reasonable to me due to the fact the low compression engine burns regular grade low octane gas and turns at such relative low speeds. NO WARRANTY NO SPECS HERE Of course if it start times too fast it could kick back.......

John T

 

[Jim.ME]

Engine warm and running at fast idle (2025 rpm +/- 25 rpm). Advance distributor until the SPARK mark on the flywheel lines up with the mark on the timing hole.

Service manuals are a good thing to have.

 

[kdl]

Yes spark is in the window at full throttle actually it takes 18 degrees on my advance timing light so for anyone else looking my full spark advance is 18 degrees . ( Tdc at idle with no mechanical advance .

 

[buickanddeere]

Not to highjack your thread. After
Installing a Pertronix on our 40 ,
The magnetic transducer would not fit the shaft . Ordered another and it fits . However the engine now only runs on one cylinder .Timed the front cylinder to the flywheel marks . Will have to ponder over it one of these days .

 

[Jim.ME]

Did you by chance change distributor caps? That will happen if a Waterloo 2-cylinder cap is used on a Dubuque engine. Plug wire terminal posts are in different locations.

 

[buckeye al]

We have a 40W which is much the same as your 420. Timing by the book has you set the word SPARK on the flywheel at the timing mark on the block. Set the point gap as specified then rotate the shaft the rotor is attached to to the fully advanced position and while holding it there rotate the distributor so that it sparks at this point.

IFF all is as it should be, it will return to zero for easy starting and advance to the spark mark at fast idle which is the full throttle no load engine speed.

Our 40 never sounded quite right. It had a rather harsh bark to its exhaust. What we found was sometime in his past somebody had installed mechanical advance springs that were way too strong for this engine & its operating speed. Used to be able to buy Delco Remy distributor spring assortments just for tinkering with timing and by installing different springs, it started fine at zero degrees and somewhat less than fast idle it was running at SPARK like Mother Deere intended.

Made a different machine out of it. The harshness of his bark went away, it had more guts, used less fuel and was easier to keep cool.

I'm guessing yours is timed this same way and if it is, I Hope that helps.

 

[buickanddeere]

Same cap and rotor . Have yet to trouble shoot it . Just installed the parts , timed it and the thing runs on one cylinder .
Will have to check if the magnet poles line up with the distributer cap .