# [SOLVED] MTD yard machines won't start



## Don Adams (Jan 31, 2012)

My engine is a 16.5hp B&S OHV, model # 313707-0162E5. I got this riding mower from a friend who had let it sit under a tree for a year. In the course of rehabbing it I pulled the blades for sharpening. The jack shaft nuts on the blade were frozen solid so I removed them by taking off both the blade pulley nuts. I also replaced the spark plug with a new RC12YC, a new gravity fuel filter and and new air filter. I adjusted the valves. After assembly It ran well and mowed evenly. I ran it for about a about an hour total when I had a melt down. I didn't torque down one of the pulley nuts enough and one of the blade and shaft assemblies fell to ground while I was in motion. I must have dragged the blade about 4'. After I had retrieved the blade and shaft assembly from under the deck I restarted the engine and made it back to the garage. It quit three times on the way. Now it won't start at all. Testing is negative for spark. Given this set of circumstances shouldn't I be thinking that some kind of mechanical damage has occurred. In particular a damaged fly wheel key that would affect the timing. Your thoughts would be appreciated.


----------



## SABL (Jul 4, 2008)

*Re: MTD yard machines won't start*

The flywheel key is generally the first thing to check.....especially if the engine comes to a dead stop (or sudden jolt), such as what often happens when the blade strikes something. Did either blade strike the mower housing?? 

Another thought is that the blade may have struck one of the interlock devices (or wire/s associated to the interlock system).


----------



## jrrdw (Jun 26, 2010)

*Re: MTD yard machines won't start*

Without knowing ALL the particulars I'm going to suggest that either there is a condinsation bubble forming or formed in the carb bowl or your devolping a safety switch issue due to it sitting then being used...Mouse chewed on the wires...


----------



## Basementgeek (Feb 7, 2005)

*Re: MTD yard machines won't start*

Hi and welcome to TSF

Even with a bad key/key way you still should have spark. You engine does not have points.

Disconnect the ground wire from the coil and see if you have spark. It will be a small guage wire from the coil.

BG


----------



## jrrdw (Jun 26, 2010)

*Re: MTD yard machines won't start*

Is there spark? You said you checked but didn't clarify if there was...Nice catch Basementgeek.


----------



## Basementgeek (Feb 7, 2005)

*Re: MTD yard machines won't start*

I took this to mean there wasn't spark



> Testing is negative for spark


BG


----------



## jrrdw (Jun 26, 2010)

*Re: MTD yard machines won't start*

Yea, I missed that 1st time around so I asked.


----------



## Don Adams (Jan 31, 2012)

*Re: MTD yard machines won't start*



Basementgeek said:


> Hi and welcome to TSF
> 
> Even with a bad key/key way you still should have spark. You engine does not have points.
> 
> ...


OK I disconnected the ground (kill switch?) wire from the coil and walla I had spark. Connected spark plug wire to plug and it runs in this configuration but wont shut off with the ignition key. Reconnected ground wire to coil to stop engine. OK besides a bad flywheel key what else could be wrong? Thanks.


----------



## Basementgeek (Feb 7, 2005)

*Re: MTD yard machines won't start*

It is NOT the keyway if it runs OK.

Dumb question here maybe, you were sitting on the seat when you tried to start when it had no spark (before you disconnected the ground wire)?

You will probably have one or more "kill" switches that are wired to ground including the ignition switch.  You are going to have to check these. 
When grounded out one or more kill switches, it grounds the coil and shuts down the engine.

Generally there is a kill switch on the seat, but there could be more. I have even seen them on the gear selector linkage.

BG


----------



## Don Adams (Jan 31, 2012)

*Re: MTD yard machines won't start*

Thanks Basementgeek for providing me with the key to solving this problem. You are right. it is something simple. I did try to start it sitting on the seat and got no spark with the ground wire attached to the coil. MTD tech info for this riding mower says if the engine will crank then the safety switches are OK on the tractor. I got the BS tech manual yesterday and and it appears that the 313700 series of engines is not equipped with a stop switch. Problem must be with the ignition switch or simply a pinched wire. Pulling out my multimeter today and will do some continuity checks. Thanks again!!!


----------



## Don Adams (Jan 31, 2012)

*Re: MTD yard machines won't start*

EUREKA!!!!!! I found that the coil ground wire had been jammed between the starter and the engine. When I removed the starter I found that 2" of the wire were flat as a pancake shorting the coil to ground. Spliced in a new length of wire and reassembled. Now the ignition switch starts, runs and stops the engine as it should. Lesson learned. Check the simple stuff first. The event with the blade pulley nut was just co-incidental.Thanks to all for your input.


----------



## Basementgeek (Feb 7, 2005)

*Re: MTD yard machines won't start*

Glad we were able to help you. Thanks for letting us know.

I will mark this post as solved.

BG


----------

