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Donald
Donald, Small Engine Technician
Category: Small Engine
Satisfied Customers: 1800
Experience:  I have 25+ years of experience repairing 2 & 4 cycle engines
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Have a 19.5 hp" Deere" OHV &S Model # 31P6 770144 83

Customer Question

Have a 19.5 hp "John Deere" OHV B&S Model # ***** 770144 83 replacement engine in a Craftsman lawn tractor 3000. At end of season (Nov.) in midst of "stop and start" job engine tried to turn over but couldn't restart. Big-engine Cat mechanic son-in-law did valve job and checked battery, fuel line etc. but is flummoxed. Why would it just stop running smoothly after several years and regular maintenance?
Submitted: 10 months ago.
Category: Small Engine
Expert:  Donald replied 10 months ago.

Hello, and thank you for choosing Just Answer. My name is***** will be happy to assist you. Will your engine start up and run briefly, if you spray a small burst of carburetor cleaner, directly into your carburetor?

Customer: replied 10 months ago.
No
Expert:  Donald replied 10 months ago.

This will leads me to believe that our problem could be ignition related. Have you checked for spark?

Customer: replied 10 months ago.
I believe my son-in-law did
Customer: replied 10 months ago.
He's not here. Can you give some "mechanic"-level suggestions to pass on to him?
Customer: replied 10 months ago.
Hello anyone there?
Expert:  Donald replied 10 months ago.

Keep in mind that an engine needs three things in order to start up and run. Fuel, Spark, and Compression. If your engine will not start, after you spray carburetor cleaner into your carburetor, then this leaves Spark and Compression to question.

Expert:  Donald replied 10 months ago.

Have your son to confirm spark first. Do you know what valve settings he used?

Customer: replied 10 months ago.
I'm sure he used the ones in the manualm - he's a pro. .004
Customer: replied 10 months ago.
that's "manual"
Expert:  Donald replied 10 months ago.

Ok. Have you tried a new spark plug?

Customer: replied 10 months ago.
He checked that
Expert:  Donald replied 10 months ago.

Ok. Did he say if he noticed spark to your spark plug, when he was checking it?

Expert:  Donald replied 10 months ago.

These are only troubleshooting questions.

Customer: replied 10 months ago.
Don't know
Expert:  Donald replied 10 months ago.

I would for you to get your son to confirm two things for me. Then you and I will have a good starting point, to continue from.

Customer: replied 10 months ago.
Ok. Shoot.
Expert:  Donald replied 10 months ago.

Ask him about the spark, and ask him if he allowed his piston to go 1/4" past Top Dead Center, before adjusting your valves.

Customer: replied 10 months ago.
Will do and get back to you. Prefer this way. How do I get back?
Expert:  Donald replied 10 months ago.

Thanks! You will get a link in your email, that links you directly back to me.

Customer: replied 10 months ago.
Roger - over and out.
Expert:  Donald replied 10 months ago.

10-4 ...

Customer: replied 9 months ago.
Had a bit of a hiccup here with other events as priorities. Son-in-law can confirm spark but wants to check his valve adjustment in case he was further around than 1/4. Back to you in two days.
Expert:  Donald replied 9 months ago.

This will be fine. Thanks for letting me know.

Customer: replied 9 months ago.
Hello Donald. Finally son-in-law (Christian) has re-done valve job and I just had the battery checked at Sears. Battery is good. When we try to start without spark plug engine turns over easily. With spark plug not even once around and battery is drained. Where to we go from here?
Expert:  Donald replied 9 months ago.

Thanks for letting me know.

Expert:  Donald replied 9 months ago.

If your battery is good, and you are 100% sure your valves are properly adjusted, then this leaves two very good possibilities. Either your starter is bad, or the compression release mechanism on your cam gear has failed.

Customer: replied 9 months ago.
Christian not here to ask tech q's. Any way to tell whether its starter or compression release?
Customer: replied 9 months ago.
Just talked w/ C, he asked if there is a way to test the compression release mechanism?
Expert:  Donald replied 9 months ago.

You will need to either swap starters with another mower, that you know is working properly, or get someone to test your starter for you. If your starter is good, then it is very likely that your cam gear will need to be replaced.

Customer: replied 9 months ago.
Is that $$$ and difficult?
Expert:  Donald replied 9 months ago.

A new cam gear can cost of to $100.00

You will need to remove your engine from your mower in order to do it. It is not too difficult.

Expert:  Donald replied 9 months ago.

I attached a link to two videos that will give you an idea of what has to be done, when replacing your cam gear.

Customer: replied 9 months ago.
Thanks.. I will get back to you in a day.
Expert:  Donald replied 9 months ago.

You are very welcome! I am not aware of a way to accurately check your compression release. Usually if your starter and battery is good, and your valves are properly adjusted, you can rest assured that your compression release is bad, if our problem still exists.

Customer: replied 8 months ago.
Finally back to you Donald. Small engine repair person informs me that I have a broken shaft and should replace the short block. He's looking but no luck yet. Can I find an inexpensive one online? Or should I get a new engine/tractor unit?
Expert:  Donald replied 8 months ago.

Is your mechanic referring to your crankshaft, or cam shaft?