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Riding Mower won't start and smokes


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06-02-05, 04:38 PM   #1  
robg
Riding Mower won't start and smokes after backfire

I have a one year old MTD Riding Mower with an 18 hp B/S engine. After putting in fresh gas, I was mowing some heavy grass for the first time this year and everything seemed normal for the starting and mowing. After about an hour when the grass got higher I shifted down and the engine backfired and a puff of smoke came out the front of my exhaust.

I haven't been able to start it since. I changed the spark plug and cleaned the wire clip. The starter kicks it over and there is some smoke coming out of my exhaust. I assume this is the gas that hasn't been burned off. I checked the carburetor bowl and it had gas in it. I read through dozens of posts and found some similar issues but none that had the solution that worked for me. The blades are attached but not engaged.

I removed the cowling to access the carb and the spark plug. It seems to me that I have more than enough fresh gas (hence the smoke). Yet I am not getting the gas to ignite. Any troubleshooting suggestions for a two left handed engineer trying to fix his mower? Would appreciate the help.


Last edited by robg; 06-02-05 at 05:11 PM. Reason: added info to title
 
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06-02-05, 05:10 PM   #2  
robg,

Welcome. What is the model number of your engine? From what you describe it sounds like a timing issue however, your model number would shed more light on the fix.....? Does it seem to turn over any different than normal?

Dave

 
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06-02-05, 05:25 PM   #3  
robg
Hey Dave,

Thanks for your quick response. BTW I love this forum!

The model number is 31P7770293E1 040220ZD01498

(Listed as an Intek 18.5HP)

The start does indeed feel different. It used to start with the throttle on low and then I could increase the speed of the engine as it warmed. Now it feels like there is a quiet almost dead spot at low throttle. It seems to want to start at high throttle but never catches at all.

Thanks again for your help and the fine welcome, Dave.


Last edited by robg; 06-02-05 at 05:58 PM.
 
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06-02-05, 06:04 PM   #4  
robg,

Being this is an over head valve engine there maybe a valve issue however, perform the easy test first. Make sure you have spark on the spark plug...?

Dave

 
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06-02-05, 06:16 PM   #5  
robg
Forgive a newbie but I don't want to get zapped. I should remove the plug and connect the wire and observe a spark at the gap while my wife is starting the engine? Do I need to hold the wire with insulated pliers and approach the engine block to provide a return path for the current?

Boy she is going to love this!

 
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06-02-05, 06:32 PM   #6  
robg,

I understand your concerns! There is a tool for this however, in a pinch, you can pull the wire from the plug. With insulated pliers; holding the wire,with wire cap pulled back, slowly advance the tip to the tip of the spark plug while turning the engine over. As you approach the plug you should see the blue spark ark from the tip of the wire to you plug. This is with the spark plug mounted in the engine. If you DO NOT touch your mower during this procedure you will be perfectly safe. If you do not get a spark. Try a new plug and repeat the procedure. Let us know?

Dave

 
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06-02-05, 06:38 PM   #7  
robg
I have spark at the gap, Dave! I just provided a return path by laying the hooked up spark plug on the metal case of the OHV. (My wife is laughing at me. LOL) I reinstalled the spark plug.

I used your method and could not see a spark. The insulating cover was obstructing the view. As I inserted the wire there was some smoke coming out and then one big backfire, sounded like a gun shot.

I reviewed my manuals and noticed there is a two year warranty on the engine. Thinking about contacting a warranty dealer.


Last edited by robg; 06-02-05 at 07:34 PM.
 
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06-03-05, 12:41 AM   #8  
That's what I was about to suggest...it's under warranty. Sounds to me like it could be a coil or a valve problem. Possibly a pinched kill wire.


"Who is John Galt?" - Ayn Rand (Atlas Shrugged)

God bless!

 
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06-30-05, 02:35 PM   #9  
robg
Turned out to be a blown head gasket. It was repaired under warranty OK. Thanks for the help, folks! I sure do appreciate it. And I bookmarked the site and I am learning a lot from reading other threads and posts. Thanks again.

 
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07-01-05, 12:00 AM   #10  
Great! Thanks for the update, and glad you got it fixed.


"Who is John Galt?" - Ayn Rand (Atlas Shrugged)

God bless!

 
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