Satoh 650G won't catch while trying to start

[GoodManners]

Here's a fun one.

Satoh 650G ran fine. Sat parked for a day and when I went to start it it wouldn't catch. When it did catch it would run for about 2 seconds and then stall, and run backwards for about 1-2 seconds pushing out the carb.

Never seen that before.

I have spark - ignition system is all new. I have air. I have gas - checked the pump and she's working, plus clear fuel line to carb is full.

Soooo it has to be timing? How does timing change from just sitting. Can an ignition module go bad in these tractors?

An internet search really doesn't come up with much. Interested in what folks think.

 

[Williy]

Not familiar with your carb but on some small
gas engines the bowl attached to the carb can get some dirt and blocks the fuel input have you tried to clean
the carb with carb cleaner??

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satoh-S650g.com is the starting point for information on the Satoh S 650 G "Bison" Gasoline Tractor with a centralized collection of manuals, part numbers, specifications, information, and helpful links to forums, service centers, online stores, and parts sources.

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willy

 

[Roadworthy]

It does sound like timing. Timing should not change from sitting but as the tractor is run the fiber piece in the distributor that activates the points does wear over time. This will alter the timing as the dwell changes. Check your point gap.

 

[rScotty]

Here's a fun one.

Satoh 650G ran fine. Sat parked for a day and when I went to start it it wouldn't catch. When it did catch it would run for about 2 seconds and then stall, and run backwards for about 1-2 seconds pushing out the carb.

Never seen that before.

I have spark - ignition system is all new. I have air. I have gas - checked the pump and she's working, plus clear fuel line to carb is full.

Soooo it has to be timing? How does timing change from just sitting. Can an ignition module go bad in these tractors?

An internet search really doesn't come up with much. Interested in what folks think.

A Satoh from the 1970s? Isn't that a distributor and coil ignition? If so, there is no ignition module.
I believe the clue is found where you say, "ignition system is all new".
Go back and recheck the firing order. Your descripton sounds like what happens when the spak plug wires are connected in the wrong sequence. Common thing to have happen.

Firing order is probably 1342.
You need to find out which tower on the distributor is #1, and then which direction the distributor rotor turns, and then which spark plug cylinder that Mazda/Satoh used as #1. The distributor towers are in sequence 1234 in the direction of rotor rotation. But the spark plugs they are connected to go in the firing sequence1342.

And when you check that, also check which cylinder on your engine is considered #1. Did they count 1234 from the front to the back of the engine? Most engine manufacturers did, but not all.
rScotty

 

[GoodManners]

This thing has been running fine for the last 3 months.
All the changes and upgrades were made months ago - including the ignition which is now a solid state ignition - no points.

 

[rScotty]

This thing has been running fine for the last 3 months.
All the changes and upgrades were made months ago - including the ignition which is now a solid state ignition - no points.

Responders rarely know the whole story. So I guess you are saying it is not a new ignition, but a used one that is known to work. That's either some new info or I missed it originally. Have you also checked compression, cam timing, and done a basic carb float job? My guess is you have also done those.

So unless someone changed the spark plug wires & firing order - worth checking - then it is difficult to troubleshoot a solid state ignition. You could replace it, I guess. That't the standard "fix". Although if doing that, you might consider replacing it with the OEM distributor/coil system.

The old distributor and coil systems were simple, reliable, inexpensive, and easy to troubleshoot.
I always recommended to my customers that they keep them intact for that reason. Can't help with solid state.

rScotty

 

[Williy]

You could get a spark plug tester from HF this
will tell you if you have spark. Check to make
sure all wires have a good connection. A loose
wire can give you fits

willy

 

[GoodManners]

So it turned out that it was the spark plugs - I changed them out and the tractor started right up and runs fine. Old plugs were carboned up (they are only 6 months old).

 

[Williy]

Clean them then when tractor no start put old plugs
in and then clean the ones that were in tractor

willy