Small Engine

Small Engine Troubleshooting Problems? Ask a Mechanic Now.

Ask an Expert,
Get an Answer ASAP!

My 17.5 Kohler OHV engine on a Craftsman riding lawn mower…

Customer Question
My 17.5 Kohler OHV engine...
My 17.5 Kohler OHV engine on a Craftsman riding lawn mower turns over but will not start and either backfires when cranking or back fires when I cease trying to start.

The aircleaner looks fine but the spark plug looks suspect and when I pull out the spark plug it is oily/gas tainted.

Any suggestions?
Submitted: 8 years ago.Category: Small Engine
Show More
Show Less
Ask Your Own Small Engine Question
Answered in 8 minutes by:
6/25/2010
Technician: Rick, Factory Authorized Trainer replied 8 years ago
Rick
Rick, Factory Authorized Trainer
Category: Small Engine
Satisfied Customers: 8,063
Experience: Outdoor Power Equipment technical trainer since 1990, covering eight states.
Verified
Did the blades hit anything or was there a sudden engine stop prior to this happening?
Ask Your Own Small Engine Question
Customer reply replied 8 years ago
No lawn mower was used last week, parked in garage, and attempted to use today.
Technician: Rick, Factory Authorized Trainer replied 8 years ago
Next step is to please check the oil level. Is it overfilled by any chance, and does it smell like gasoline?
Ask Your Own Small Engine Question
Customer reply replied 8 years ago

Oil does not smell like gas, but my son did add "some" oil recently and the oil is a bit beyond full. Machine is due for an oil change.

Technician: Rick, Factory Authorized Trainer replied 8 years ago

If it's overfilled, and it doesn't take much, it could simply be pushing the oil through the breather and back through the carb resulting in your oil-fouled plug. That would be a good place to start then see how it behaves at that point. Oil i the carb will also affect metering which can result in backfiring, although it could also be a timing or valve issue.

 

Let's pick this conversation up again after the oil situation is address and see what the next logical step, if necessary, is.

 

 

Ask Your Own Small Engine Question
Customer reply replied 8 years ago

Rick I'm not sure if my previous response was sent...have been gone for the weekend.

 

The engine was slightly overfilled with oil. I drained oil replaced oil and filter. Engine still backfires...coud this be a timing issue and if so how difficult to reset timing on this engine.

 

Thanks,

Kendon

Technician: Rick, Factory Authorized Trainer replied 8 years ago

Backfiring is often a sheared flywheel key. Engines of recent manufacture will all have solid state ignition systems, so the air gap between the flywheel and the coil, plus the position of the flywheel determined by the key is what controls timing as long as everything inside the engine is in good shape and correctly assembled.

 

I would check the flywheel key at this point as the most likely problem.

 

Can you let me know the numbers off the engine? I can better assist once I know exactly what engine this is.

 

graphic

Ask Your Own Small Engine Question
Customer reply replied 8 years ago

engine #'s starting at the top of the plate:

4khxs.4902gb

490cc

cv490s

27532

serial # XXXXX /p>

oem- 190816

 

Thanks

Technician: Rick, Factory Authorized Trainer replied 8 years ago

Thank you for that.

 

I would check the flywheel key as a starting point. I'm linking to a shop manual below for reference. You can see how to do this on page 9.9. You don't need to fully disassemble everything, just remove the bolt and washer so you can see if the key is lined up exactly square between the flywheel and crankshaft slots. f it's not, the engine will be out of time.

 

http://bit.ly/aMjHxH

 

Let me know...

Ask Your Own Small Engine Question
Was this answer helpful?

How JustAnswer works

step-image
Describe your issueThe assistant will guide you
step-image
Chat 1:1 with a technicianLicensed Experts are available 24/7
step-image
100% satisfaction guaranteeGet all the answers you need
Ask Curtis B. Your Own Question
Curtis B.
Curtis B.
Curtis B., Technician
Category: Small Engine
Satisfied Customers: 15,342
15,342 Satisfied Customers
Experience: have worked on and around most engine models for 35 yrs./Polaris ATV expert

Curtis B. is online now

A new question is answered every 9 seconds

How JustAnswer works:

  • Ask an ExpertExperts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional AnswerVia email, text message, or notification as you wait on our site. Ask follow up questions if you need to.
  • 100% Satisfaction GuaranteeRate the answer you receive.

JustAnswer in the News:

Ask-a-doc Web sites: If you've got a quick question, you can try to get an answer from sites that say they have various specialists on hand to give quick answers... Justanswer.com.
JustAnswer.com...has seen a spike since October in legal questions from readers about layoffs, unemployment and severance.
Web sites like justanswer.com/legal
...leave nothing to chance.
Traffic on JustAnswer rose 14 percent...and had nearly 400,000 page views in 30 days...inquiries related to stress, high blood pressure, drinking and heart pain jumped 33 percent.
Tory Johnson, GMA Workplace Contributor, discusses work-from-home jobs, such as JustAnswer in which verified Experts answer people’s questions.
I will tell you that...the things you have to go through to be an Expert are quite rigorous.

What Customers are Saying:

You did one super job of explaining to me everything there is to know about this fridge. I'm looking forward to asking you questions in the future.

JimmyBagley, IA

Wonderful service, prompt, efficient, and accurate. Couldn't have asked for more. I cannot thank you enough for your help.

Mary C.Freshfield, Liverpool, UK

This expert is wonderful. They truly know what they are talking about, and they actually care about you. They really helped put my nerves at ease. Thank you so much!!!!

AlexLos Angeles, CA

Thank you for all your help. It is nice to know that this service is here for people like myself, who need answers fast and are not sure who to consult.

GPHesperia, CA

I couldn't be more satisfied! This is the site I will always come to when I need a second opinion.

JustinKernersville, NC

Just let me say that this encounter has been entirely professional and most helpful. I liked that I could ask additional questions and get answered in a very short turn around.

EstherWoodstock, NY

Thank you so much for taking your time and knowledge to support my concerns. Not only did you answer my questions, you even took it a step further with replying with more pertinent information I needed to know.

RobinElkton, Maryland

< Previous | Next >

Meet the Experts:

Curtis B.

Curtis B.

Technician

15,342 satisfied customers

have worked on and around most engine models for 35 yrs./Polaris ATV expert

Rick

Rick

Factory Authorized Trainer

8,063 satisfied customers

Outdoor Power Equipment technical trainer since 1990, covering eight states.

Jon K.

Jon K.

Small Engine Diagnostic Expert

2,995 satisfied customers

Gold certified Stihl tech, Service Manager for a rental/repair shop.Certified in most small engines

James W

James W

Small Engine Troubleshooting Expert

2,986 satisfied customers

7 years as Mechanic & Parts Manager for Brother who has Owned Lawn & Garden Repair shop for 35 years

Vince O.

Vince O.

Small Engine Technician

2,927 satisfied customers

Over 30 years experience repairing lawn and garden equipment. Chainsaws, mowers,blowers and trimmers

Wayne

Wayne

Engine Rebuilder

2,041 satisfied customers

many years on egine rebuilding, lawn mower,roto tiller,Truck,and small engines

RUSS

RUSS

SERVICE TECHNICIAN

1,723 satisfied customers

28 YEAR SERVICE TECHNICIAN

< Previous | Next >

Related Small Engine Questions
I have a craftsman Lt2000 Riding Mower. Kohler pr0 17 hp ohv
I have a craftsman Lt2000 Riding Mower. Kohler pr0 17 hp ohv model #CV490S. turns over ocasially backfires won't start. (suspected gas in oil, Changed oil, filter, spark plug) … read more
Curtis B.
Curtis B.
Technician
Associate Degree
15,342 satisfied customers
My riding lawn mower turns but will not start. checked and
my riding lawn mower turns but will not start. checked and can see spark. tried spraying gas into intake. It was running fine, I stopped for water and when I came back it will not start. not even try.… read more
Curtis B.
Curtis B.
Technician
Associate Degree
15,342 satisfied customers
My Kohler 17.5 hp CV490s engine on my Craftsman riding mower
My Kohler 17.5 hp CV490s engine on my Craftsman riding mower won't start. It had leaking fuel issue to start with. When I cranked the engine, it did not start but had a loud exploding noise (like a gu… read more
ranwell1
ranwell1
CEO
High School or GED
5,039 satisfied customers
I have a craftsman 6500 riding mower with a 27 hp Kohler motor that was running but surgin
I have a craftsman 6500 riding mower with a 27 hp Kohler motor that was running but surging. After I took it apart and cleaned up the aircleaner it will not start...the starter bendix rod is fully ext… read more
Curtis B.
Curtis B.
Technician
Associate Degree
15,342 satisfied customers
Yesterday my craftsman mower just died while I was driving
Yesterday my craftsman mower just died while I was driving slowly around the yard. It has a kohler cv14s 14hp engine. I have since put in a new spark plug, air filter, fuel filter and changed the oil … read more
Briggs-Fan
Briggs-Fan
1,278 satisfied customers
I have a kohler craftsman riding lawn mower. replaced fuel
I have a kohler craftsman riding lawn mower. replaced fuel filter,air filter, spark plus, cleaned carburater and it still wont start....was backfireing when it ran last.… read more
wheelhrs
wheelhrs
Vocational, Technical or Trade Scho
424 satisfied customers
I have a craftsman riding mower single cylinder with a 17 HP
I have a craftsman riding mower single cylinder with a 17 HP Kohler engine. Ran fine the last time it was used about 3 weeks ago. Went to start it and all it does is backfire. Have checked the flywhee… read more
Chris Huber
Chris Huber
President
Vocational, Technical or Trade Scho
501 satisfied customers
I have a 17.5 Kohler engine on my craftsman riding mower. I
I have a 17.5 Kohler engine on my craftsman riding mower. I love it. the engine starts well and runs for about 15 minutes then starts to backfire and I have to shut the mower deck off and turn down th… read more
Curtis B.
Curtis B.
Technician
Associate Degree
15,342 satisfied customers
I have a Craftsman 42 inch lawn mower with a 14 hp Kohler engine.
I have a Craftsman 42 inch lawn mower with a 14 hp Kohler engine. ModelNNN-NN-NNNN Engine backfires but will not start. Checked safety switch under seat, gas & air filters, key on flywheel shaft - all… read more
Rick
Rick
Factory Authorized Trainer
8,063 satisfied customers
I own used Craftsman Lawn Tractor ModelNNN-NN-NNNN 17.5 HP
I own used Craftsman Lawn Tractor ModelNNN-NN-NNNN 17.5 HP 42" Mower Electric Start Auto Transmission ran fine all last season over winter battery drained fianlly died seems charing system faulty just… read more
J.R.
J.R.
Vocational, Technical or Trade Scho
7,173 satisfied customers
I have a 17.5 hp craftsman riding lawn mower, i am having a
I have a 17.5 hp craftsman riding lawn mower, i am having a issue with it cutting off after 30 mins of mowing. i recently changed the oil, spark plug, air filter, fuel filter, but am still having the … read more
Rick
Rick
Factory Authorized Trainer
8,063 satisfied customers
I have a 18 hp electric start 42 mower Craftsman automatic
I have a 18 hp electric start 42" mower Craftsman automatic lawn tractor (modelNNN-NN-NNNN. It was running rough and backfired. I did a service on it - oil, oil filter, air filter, gas filter and spar… read more
Curtis B.
Curtis B.
Technician
Associate Degree
15,342 satisfied customers
i bought a used troy buit pony 42 cut riding lawn mower last
i bought a used troy buit pony 42" cut riding lawn mower last fall. I has a 17.5 HP Briggs and Stratton engine. When I bought and picked it last fall it ran fine after cold start and flooded i think c… read more
Rick
Rick
Factory Authorized Trainer
8,063 satisfied customers
My lawn mower was working fine when i put it in the storage
My lawn mower was working fine when i put it in the storage shed at the end of last summer, this year when i raised the seat up there was a rats nestover the coil so i put a new coil and spark plug an… read more
RUSS
RUSS
SERVICE TECHNICIAN
Vocational, Technical or Trade Scho
1,723 satisfied customers
I have a Kohler Pro 17.5 HP OHV in a Craftsman Tractor will
I have a Kohler Pro 17.5 HP OHV in a Craftsman Tractor will not start. I get spark and fuel, valves working, fuses are good, getting some back fire.… read more
J.R.
J.R.
Vocational, Technical or Trade Scho
7,173 satisfied customers
I have Kohler Command 16.5 OHV Model #CV16S in a Craftsman
I have Kohler Command 16.5 OHV Model #CV16S in a Craftsman riding mower. I cannot get any fire to the plug. Tried a new coil and still no fire. Would appreciate any suggestions. Thank you.… read more
Rick
Rick
Factory Authorized Trainer
8,063 satisfied customers
My lawn tractor, a craftsman 17.5 hp Kohler engine, begins
My lawn tractor, a craftsman 17.5 hp Kohler engine, begins to sputter and cut out (eventually off) whenever the gas tank reaches about one-half empty. I have to fill the tank to get the engine started… read more
Delsley Jr
Delsley Jr
Handyman & JustAnswer Expert
IT Certificate
552 satisfied customers
I have a craftsman riding lawn mower and it will run fine for
I have a craftsman riding lawn mower and it will run fine for a few minutes then stall like it is out of gas. If I wait I can restart it, but it won't stay running long. I put in new gas, the gas filt… read more
J.R.
J.R.
Vocational, Technical or Trade Scho
7,173 satisfied customers
Disclaimer: Information in questions, answers, and other posts on this site ("Posts") comes from individual users, not JustAnswer; JustAnswer is not responsible for Posts. Posts are for general information, are not intended to substitute for informed professional advice (medical, legal, veterinary, financial, etc.), or to establish a professional-client relationship. The site and services are provided "as is" with no warranty or representations by JustAnswer regarding the qualifications of Experts. To see what credentials have been verified by a third-party service, please click on the "Verified" symbol in some Experts' profiles. JustAnswer is not intended or designed for EMERGENCY questions which should be directed immediately by telephone or in-person to qualified professionals.

Disclaimer: Information in questions, answers, and other posts on this site ("Posts") comes from individual users, not JustAnswer; JustAnswer is not responsible for Posts. Posts are for general information, are not intended to substitute for informed professional advice (medical, legal, veterinary, financial, etc.), or to establish a professional-client relationship. The site and services are provided "as is" with no warranty or representations by JustAnswer regarding the qualifications of Experts. To see what credentials have been verified by a third-party service, please click on the "Verified" symbol in some Experts' profiles. JustAnswer is not intended or designed for EMERGENCY questions which should be directed immediately by telephone or in-person to qualified professionals.

Show MoreShow Less

Ask Your Question

x