Small Engines (Lawn Mowers, etc.)/snow blower light


QUESTION: Hello I have a craftsman LH318sa-156554g model snowblower with a tecumseh engine on it. Its headlight was really dim i mean not even enough to see a thing. So i added a LED utility light using the same wires to the machine mounted on the side and it worked well. The next day i went to use it the LED light was burned out. Thinking it was the light i returned it and got the same light as a replacement. Same deal used it for an hour, then took a break and went out to clear more snow, the light never came back on. So i took the light apart from the rubber housing and on the back of the lights little transformer i believe was black and melted some of the plastic housing that contained it. I was wondering why this is happening as at least the oem light still worked but was dim. I checked the VAC coming out and it was about 6.30 and the DC was about 1.3, Am i missing something here or do i need to add a voltage rectifier to it? Or maybe a voltage regulator? Im kind of lost on this as there is no one who can help me... thank you

ANSWER: Using the service manual via the URL below, can you identify your charging system?

You may need to clean some black engine paint to identify the wire color...just lightly scrape or use some scotch brite to remove the paint.

This URL maybe helpful as well:

Start on page 32 and use the manual to correctly identify your charging system.

Let me know if you have an AC or an AC/DC charging system and which type (amp) you have.

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QUESTION: Thank you Eric for the help! I have the 18 watt AC lighting adaptor. There is only 1 yellow plug coming out of the engine that the OEM light plugged into. I am not sure of the amps on this as I don't know how to use my multimeter to check this. I just lost on this as electrical systems are kinda foreign to me. So I hope that helps...if not I'll keep digging. Thanks again

Is your alternator the 18 Watt A.C. Lighting alternator part number 611111?  I believe it is.

There are formulas to calculate amps if you know volts, watts, and power factor.  Not knowing the true power factor creates some error in the formula but if the power is  18 watts and the volts is 10 volts AC you will get about 1.8 amps with a power factor of 1.

Roughly you can say 2-3 amps are available.

I suspect someone installed a car light...see this all the time...the SB alternator just can't power the car light to make is bright.  You need a mower or OEM light.

As for the LED, I'm guessing it it looking for at least 12 volts DC or something diffent if it is not intended to be used in an auto application.  The lower voltage of the SB maybe causing the LED unit to over heat causing them to fail.  I'd get a mower or AC bulb and see if that fixes your problem.


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Eric A. Jones


Lawnmower Repair . Certified Master Service Technician from B&S. Have 23 years experience on B&S, Lawn Chief, Weed Eater, Echo, Peerless, Wheel Horse, Snapper, Atlas, MTD, McCulloch, Homelite and many other numerous brands. Specialize in electrical repair.


Born and raised in the midwest. Started tinkering with engines when I was about 14 on my Suzuki RM-80. I began lawn mower repair at a small hardware store. I knew absolutely nothing. I read lots of repair manuals and met an older fellow who taught me many lessons. I continued working on small engines through high school and paid my way through college working on mowers at the same hardware store. Decided to get away from the midwest and mower repair so I joined the Air Force. I repaired air traffic control electronic equipment and ended up in Hawaii where I got a part time job at Small Engine Clinic. I gained a lot of experience from the Small Engine Clinic and had a blast repairing small engines. I then took the Briggs and Stratton Master Service Technician test and earned my MST. I then traveled to Wisconsin where I attended the factory update training seminar and received formal training. Continued working on mowers part time as I completed 20 years of military. Retired from the military on a Friday and continued in the lawn and garden industry the next Monday.

MAS Aerospace Operations BA Mathematics AAS Electronic Communications AAS Electronic Technology

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