# Timing adjustment on gasoline generator engine



## conaga (May 2, 2021)

Hi all,
I have a question about the ignition timing on gasoline generator engines.
From what I understand, in vehicle engines the timing is usually controlled by a distributor (old) or by electronic means.
My question is, what controls the ignition timing of a small single-cylinder engine for a generator in the few kW range?
Is this also electronic or still by distributor ?

Thanks,
C


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## Browse Deweb (Jan 16, 2021)

Usually, small engines with a single cylinder have spark timing that is tied to the crankshaft or flywheel position associated with cylinder top dead center (TDC) via timing marks. There may be small adjustments available based on electrical or mechanical changes to these positions (sensors, set screws, etc.). Multiple cylinder engines will have more complicated timing systems to ensure all of the cylinders are working together and firing as each one reaches it's TDC position.


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## ToolLover (Jan 13, 2020)

Iowagold has another take on timing of small engines as best I remember.
It goes like this: The spark plug gap has a direct effect on timing.
Maybe Paul will explain this spark plug setting and how the gap effects timing and to what degree.
His explanation was simple to understand and made sense.


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## iowagold (Jan 22, 2020)

conaga said:


> Hi all,
> I have a question about the ignition timing on gasoline generator engines.
> From what I understand, in vehicle engines the timing is usually controlled by a distributor (old) or by electronic means.
> My question is, what controls the ignition timing of a small single-cylinder engine for a generator in the few kW range?
> ...


so conaga are you having a time issue???
or are you wanting to change time for fuel?

first things first what brand and exact model of engine?
exactly how much time do you need and what direction? advance (for fuels like natural gas) or retarded?
some engines are super easy to mod time..
others you need a machine shop if you need more than 2-4 deg...

pm me for one on one help.


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## conaga (May 2, 2021)

Hey guys,

thanks for answering my post. 

There's a video on Youtube which shows an interesting way of finding the ignition timing on small engines,
but it looks quite involving : 




@iowagold thanks, I have sent you a pm

Cheers,

C


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## conaga (May 2, 2021)

Hi all,

I've managed to borrow a gen-set that I can play with.
It looks like this one has an external flywheel with a
classical magneto ignition circuit, almost exactly like this :










The only difference seems to be that on this engine, the breaker
arm contact is connected in series with the condenser.

Below are some pictures to clarify :

















I understand how the magneto ignition from the diagram works but
I'm not sure about this particular configuration.

What kind of trigger is the contact point in this case?
Does it connect/disconnect to ground as the shaft rotates?

I have tried measuring the continuity of the contact point to ground with a
multimeter and rotating the flywheel but I'm unsure about my readings.
I might try it later today or tomorrow with a different multimeter.

EDIT: I have measured the contact point wire continuity to ground with
another multimeter and it gives a changing resistance, which makes me
think that there is an active component in there (capacitor?). Also when
I measure the continuity of the component which is now marked as
capacitor in my pictures, it gives a ~600 ohm resistance when measured
with positive on the black lead (which goes to point contact) and 
open-loop when measured with positive on red lead.

What am I missing? Maybe someone with more insight can help me clarify this

cheers

C


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## drmerdp (Apr 10, 2018)

The magneto has a primary and a secondary winding. The “switch is internal to the magneto, The flywheels magnet passes by the coil, at the peak of the magnet passing by the two poles an internal switch closes the contact in the primary winding, sending the current through the secondary winding which produces the high voltage capable of a high energy spark that Can jump the gap in the spark plug and hot enough to ignite the fuel air mixture.

To answer your earlier question of ignition timing, a offset woodfuff key can be used to advance or retard ignition timing. Honda GX engines producedafter a certain year has a built in timing advance at low RPMs to improve starting.

The item You have listed as “capacitor“ is a component of the low oil shutoff. Its described as an oil alert sensor. I’m not entirely sure of its purpose considering the actual float switch is in the engine block.


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## iowagold (Jan 22, 2020)

you could make a custom mounting plate for the coil..
make it out of thin stainless steel..
and make it a 2 plate slip design...
then you could get 20 deg or more fixed time movement...

I still think you would be better off with full efi system and then just use a crank shaft sensor..
then you could map the fuel air spark (lambda)
and it will adjust according to speed and load better.

or use a spin turn remote adjust cable to dial in the advance!
they used to have manual advance on the old cars like the model T and model A ford trucks and cars.


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## Ground Fault (Jun 9, 2020)

O-ring the cylinder and head, dial another six degrees of advance into it, burn 104 octane and you'll get another 500 watts out of it...just don't increase the compression. High compression trims off peak rpms.

In a shifter kart. DO NOT LISTEN TO THE MAN BEHIND THE CURTAIN!!!


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## Olaseni7777 (6 mo ago)

iowagold said:


> so conaga are you having a time issue???
> or are you wanting to change time for fuel?
> 
> first things first what brand and exact model of engine?
> ...


Hello great Engr. 
Please I want to retard Gx160 for hydrogen gas as source


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## pipe (Jun 27, 2021)

Olaseni7777 said:


> .. to retard Gx160 for hydrogen gas as source


On pure hydrogen in Nigeria ?

Maybe this will give you some ideas (hint: not cheap conversion)


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## Olaseni7777 (6 mo ago)

pipe said:


> On pure hydrogen in Nigeria ?
> 
> Maybe this will give you some ideas (hint: not cheap conversion)


Yes because of pure hydrogen gas


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## Columbotrek (11 mo ago)

conaga said:


> Hi all,
> I have a question about the ignition timing on gasoline generator engines.
> From what I understand, in vehicle engines the timing is usually controlled by a distributor (old) or by electronic means.
> My question is, what controls the ignition timing of a small single-cylinder engine for a generator in the few kW range?
> ...


Easy to do. Go-kart racers do it standard practice. Videos on youtube shows how its done. This is a rough recap of the process. Remove flywheel from the crankshaft taper. Remove the key. It will not be used. Make markings on the end of the crank taper to extend an index from the keyway slot. That part is critical. Take a little time to clean up the tapers on both the crank and flywheel. Use a little valve lapping compound and lap the two tapers together. Clean off the lapping compound and install the flywheel. Without the key you are free to place the flywheel at and timing you wish. Just use the key slot on the fly wheel and the marks on the shaft taper as the stock position which from the flywheel timing can be easily retarded or advanced and then tightened down. The two tapers bind the position and will not slip. Think a drill press spindle. Just two tapers and they do not slip either.


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