Gravely Puzzeled???

[exendogirl]

Gravely C8 walk-behind with electric start has no spark, while cranking, but will bark after releasing starter button, and the engine slows. This makes no sense at all to me. Maybe somebody out there has had the same thing happen to them. Any input would be appreciated.

 

[DaveBN]

You don't have enough power to the coil when the starter is engaged. Possibly a bad or weak battery or a poor connection somewhere.
Dave.

 

[TomIn]

You don't have enough power to the coil when the starter is engaged. Possibly a bad or weak battery or a poor connection somewhere.
Dave.

Over the years there have been a variety of names associated with Gravely two wheel tractors. To me, C8 refers to a Gravely engine tractor that uses a magneto and has no external coil. The battery is used only to power the starter and not the ignition.

I have several electric start Gravely engine two wheel tractors, but haven't attempted to use them for over 20 years. As I recall, the start switch (button) was foot operated and the kill switch was generally mounted on the end of one of the handle bars. It's been 50 years since Gravely used its own engines, and is quite possible that someone has changed the wiring sometime along the line. Have you owned the tractor long enough for it to actually run like expect? Are you trying to start the tractor by pushing a button with your foot or by pushing what might actually be a kill switch on the handle bar?

Do you have manuals for your Gravely? If not, there are several places where manuals can be downloaded for free. One example is

GravelyManuals.com - OldGravelys.Info: Gravely Manuals & Parts Lists: Walk-Behind Tractors

 

[DaveBN]

Well now I'm puzzled. I thought C 8 was Kohler powered with external coil. If not then disregard my previous post. If you have a Gravely engine with a magneto then I suspect something is wrong with the magneto. Please post again so we can help you.
Dave

 

[TomIn]

Well now I'm puzzled. I thought C 8 was Kohler powered with external coil. If not then disregard my previous post. If you have a Gravely engine with a magneto then I suspect something is wrong with the magneto. Please post again so we can help you.
Dave

I'm a geezer who did not get involved with Gravely tractors until 1990's.

As I tried to explain, the names (and usage of various names) is somewhat of a mystery. Through the early 1960's two wheel Gravely tractors were designed as models L, LI, or LS. It appears that when the HP was increased to 6.6 (or 7.6) Gravely began to call them Convertible tractors. At about the same time Gravely introduced tractors using Kohler engines. These were called Commercial tractors.

Everyone has their opinion, but C8 is commonly used to describe a Gravely engine Convertible tractor with an 8 speed (4 forward and 4 reverse) transmission. The Commercial tractors used mostly 10 and 12 HP Kohler engines although a few 8HP engines were used in the series. When the Gravely engines were discontinued, Gravely switched to numbers (eg 500) for model designations.

As far as I know, all the electric start Kohler engine two wheel tractors used a key ignition to start and stop the engine. The Gravely engine electric start models generally had a foot operated push switch to operate the starter although I have seen some where the owner preferred a hand operated key, button, or switch of some other sorts and replaced the foot operated switch with a solenoid and hand operated "switch" of his liking on the handlebars. The Gravely engine tractors had a kill switch on the side of the magneto OR this grounding circuit was extended to the end of the handlebar where a kill "button" was used.

Anything is possible. This might include a person trying to use an electric start Gravely engine tractor for the first time and thinking that the kill switch button was something that needed to be depressed for the engine to start.

 

[DaveBN]

Thank you tomin. Until recently I didn't know Gravely made so many different models. It's way more confusing than I had thought.
Dave

 

[exendogirl]

Gravely C8 walk-behind with electric start has no spark, while cranking, but will bark after releasing starter button, and the engine slows. This makes no sense at all to me. Maybe somebody out there has had the same thing happen to them. Any input would be appreciated.

Let me clarify. The Gravely is a 7.6 hp Gravely engine with an 8 speed transmission. The ignition system is a magneto. There is no kill switch on the handlebars, just the button on the side of the magneto. No Kohler engine. No coil. The engine seems to spin quickly enough. When the starter switch is released, and the engine winds down, then I get a bark out of it. Its got me stumped!

 

[timcasbolt]

Is the flywheel key in good shape?

 

[DaveBN]

You may have a sticky valve or weak or broken valve spring. That would cause the valve or valves to not operate fast enough at full cranking speed. Have you actually checked for spark while running the starter? I like the flywheel key idea also.
Dave

 

[Farmalldude45]

You may have a sticky valve or weak or broken valve spring. That would cause the valve or valves to not operate fast enough at full cranking speed. Have you actually checked for spark while running the starter? I like the flywheel key idea also.
Dave

Flywheel has nothing to do with mag on a Gravely. Mag is driven off end of exhaust cam. Does the engine continue to run after you get the "bark"? If yes, I suspect you have impulse issues. I think it may be possible that your impulse coupling is disengaging at cranking speeds and then engaging as speed drops off. Do you hear the impulse clicking while cranking? If not examine, impulse for problems. I dont know what could cause early disengagement of impulse, but maybe the problem will be obvious. Maybe weak, broken, or missing spring?

 

[exendogirl]

The engine seem to want to run after the "bark" but dies off. Trying to engage the starter forces the same results, a "bark when the engine slows down. I don't recall hearing the impulse clicking when the engine is cranking. As strange as it seems, the impulse seems to be working backwards. I guess I'm taking the magneto off for a closer look. Don't know that muck about them, but as they say "Its broke now." I'll download a magneto manual before I take it apart.

 

[Farmalldude45]

The engine seem to want to run after the "bark" but dies off. Trying to engage the starter forces the same results, a "bark when the engine slows down. I don't recall hearing the impulse clicking when the engine is cranking. As strange as it seems, the impulse seems to be working backwards. I guess I'm taking the magneto off for a closer look. Don't know that muck about them, but as they say "Its broke now." I'll download a magneto manual before I take it apart.

I dont see where you indicate if this is a new problem or occurred after work has been done to the engine. I'm wondering if the mag has been replaced and the replacement is the wrong rotation. Have you verified timing? It's been a long time ago, but I seem to recall that setting timing was a bit tricky.

 

[Farmalldude45]

I dont see where you indicate if this is a new problem or occurred after work has been done to the engine. I'm wondering if the mag has been replaced and the replacement is the wrong rotation. Have you verified timing? It's been a long time ago, but I seem to recall that setting timing was a bit tricky.

I might remind you that it has been reported that 80% of ignition problems are carburetor related and vice versa. To narrow the problem, remove air cleaner hose and give it a shot of starting fluid while cranking. If it starts and runs briefly, you have a carburetor problem.

 

[Farmalldude45]

I might remind you that it has been reported that 80% of ignition problems are carburetor related and vice versa. To narrow the problem, remove air cleaner hose and give it a shot of starting fluid while cranking. If it starts and runs briefly, you have a carburetor problem.

As a final note, check the point gap. I've had points that were almost completely closed do strange things to engine performance.