ignition timing

[shinytopgeezer]

In the small engine world of single cylinder and small twins of lawn maintenance types, do the newer engines have ignition advance/retard systems in them? Remembering older (non-computer) auto engines this was done using flyweights in the distributor and vacuum diaphragms. Then along came computers and sensors to accomplish the advance/retard in the ignition. With all the advances in electronics, do any of the small engines in our world have a variable ignition timing built in to them for easier starting and lower fuel consumption. Seems it should be a no-brainer. Anything in the aftermarket?:anyone:

 

[ILENGINE]

The larger Kohler command engines, I think some of the new Briggs engines, and some of the high end chain saws (Stihl, Dolmar, Husqvarna) use electronic variable timing ignition modules.

 

[BAGGMAN's MOTOR SHOP]

kohler 15-16 hp single cyl I have seen on Craftsman Riders that have a CDI box. If i am not mistaken retards ignition for easier starting and then advances. I have seen them without it too.

 

[motoman]

the retard sounds useful, but don't know why much advance is necessay on ? 3200 rpm engines that rely on torque mainly

 

[ILENGINE]

The spark advance allows the engine manufacturers to increase hp with the same size block as the lower hp engine. Example, Kohler has a 18,20,22 hp engines that used the same block. the difference between the 18 and 20 was a throttle butterfly stop that only allowed the throttle plate to open half way. The difference between the 20 amd 22 was the smart spark. spark advance module.

 

[shinytopgeezer]

the retard sounds useful, but don't know why much advance is necessay on ? 3200 rpm engines that rely on torque mainly

Well in the hotrod-small block chevy world they start well with 4 to 6 degrees initial timing, but by 3000 rpm the "centrifical" advance is all in, usually around 34 to 36 degrees total, depending on the engine. I don't recall how much farther the vacuum advance would pull it at light throttle, but you could sure tell it at the gas pump if the vacuum was un-hooked!!!! I sure wouldn't want to yank the cord on a little engine with 30 degrees initial timing!!!!

 

[impalass]

In the small engine world of single cylinder and small twins of lawn maintenance types, do the newer engines have ignition advance/retard systems in them? Remembering older (non-computer) auto engines this was done using flyweights in the distributor and vacuum diaphragms. Then along came computers and sensors to accomplish the advance/retard in the ignition. With all the advances in electronics, do any of the small engines in our world have a variable ignition timing built in to them for easier starting and lower fuel consumption. Seems it should be a no-brainer. Anything in the aftermarket?:anyone:

Lawn boy uses a 2 stage coil on the older F engines.

 

[motoman]

ILENG, thanks, the increase could not be much, 1-2HP?