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bigdog46

Briggs 16 hp starting problem

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bigdog46
I have a Simplicity tractor with a 16 hp Briggs 326431 engine that has a starter generator on it. There are times when I attempt to start it that it refuses to turn over when it is going into the compression stroke. The battery is at full charge and the generator charges properly when the engine is running. If I take a wrench and turn the crankshaft a small amount to get thru the compression stroke, often it will go ahead and start. Do you think the starter is weak or something else may be causing the problem? I pulled the head and cleaned all the carbon off piston, valves & head. Thanks in advance for your help.

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joshuaareed
My 3012 does that also, so I just turn the starter generator pulley by hand a quarter turn and she takes right off. I can actually turn the pulley from the seat on mine. Sorry I didn't answer your question.

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Dark
the gen/starter is not a per-magnet motor so when you turn the key you also have to fill the field windings, This said check the size of the battery cable to the gen/starter heavier the better the field wire should be of good gauge like 8 or 9 AG last look at the CCA of the battery some batteries have as low as 180 CCA (Cold Cranking Amps) Cold Cranking Amps is a rating used in the battery industry to define a battery's ability to start an engine in cold temperatures. The rating is the number of amps a new, fully charged battery can deliver at 0° Farenheit for 30 seconds, while maintaining a voltage of at least 7.2 volts, for a 12 volt battery. The higher the CCA rating, the greater the starting power of the battery will be. I would suggest 300 CCA or better.

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D-17_Dave
As said above, check the cables for weak connections. IF the belt isn't slipping and the battery is able to supply enough amps, load the system by trying to start the engine. If ANY of the connections get warm or hot then your loosing electrical flow at that connection and it should be replaced. If no connection can be found hot, try hooking some jumper cables to the tractor battery and if it spins good then your battery is too small to handle the load needed to spin the engine.

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goatfarmer
My brother in law had a MTD with a Briggs vertical on it, and it would do the same thing. What was happening is the carb was leaking a small amount of gas into the cylinder, and hydrolocking the engine. Putting a fuel shutoff in the line took care of it. just a thought.....:p

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bigdog46
Al, if the valve to tappet clearance is too wide, how do I decrease it? I pulled the breather cover expecting to see adjustable tappets but there were none. Do I have to have the ends of valves built up by welding or purchase new valves? Thanks. Gary.

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Glen112
On 9/24/09, Mark (Dark)said:
quote:
the gen/starter is not a per-magnet motor so when you turn the key you also have to fill the field windings, This said check the size of the battery cable to the gen/starter heavier the better the field wire should be of good gauge like 8 or 9 AG
I have a similar problem with my 725 with cranking. I have been re-building this tractor from pieces/part and replaced all wiring from scratch. I know I have some fairly light gage wire to the "G" and "F" connections on the regulator. When I first read the above quote, I thought it was the answer to my problems. It really made made sense, but after thinking more about it, I have some questions, mainly for Mark. First, I need to confirm that this is the same S/G setup as I have on my tractors (725, Big Ten, and B-112). If it is, I don't understand the need for the heavier field wire to get more cranking power out of the starter. If I am not mistaken, you can crank the engine without any connection to the field terminal. That tells me that the S/G does not rely on "filling the field windings" to operate as a starter. It was my impression that as a starter, the only thing you really need is a ground and 12v to the starter terminal. I thought that all the other connections to the S/G and the voltage regulator were on the "generator" side to regulate a charging system for the battery. Another question on these S/G units, are the brushes replaceable, and if so, where can they purchased? Answers to the above questions would certainly be appreciated. Thanks, Glen

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