18.5 hp sit down starting mystery

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  #1  
Old 08-29-09, 08:20 AM
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18.5 hp sit down starting mystery

I have a Craftsman mower(18.5hp.#917.275810) It starts well 80% of the time. The other 20% is the mystery. When I turn the key, the starter engages but will not turn the engine. It sounds like its against compression and won't turn. I replaced the battery and still with the same results. The problem is the same whether I have just used it and I'm trying to start it up again or if its been sitting in the garage for a week. It sounds like either retarded or advanced too much. Since I don't know where even begin to look, I am asking for advice on how to check the timing or set the valves on this kind of vehicle. Thanks, Joe A
 
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Old 08-29-09, 11:22 AM
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It's probably the compression release on it isn't working right because of a valve adjustment issue.

If you look at the recent posts here in this section there is one on "Troybilt mower won't start" (7-31-09). 31yeartech put a diagram in those postings on how to do the valve adjustments on a Briggs. You just have to make sure the clearances are for your engine. Those settings should be in your owners manual.
 
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Old 08-29-09, 01:48 PM
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Thanks marbobj,

The procedure/specs in the "Troybuilt" thread is for a twin cylinder, Joe needs the single cylinder specs below and as you mentioned that should solve his starting issues.







Good Luck
 
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Old 08-29-09, 02:30 PM
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18.5 hp Craftsman

Thanks to marbobj and to 31YTech, I will try your advice. Since the clearance is different, how do I tell which is the intake and which is the exhaust valve? Thanks, Joe A
 
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Old 08-29-09, 03:06 PM
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Exhaust is the top, Intake is bottom.....
 
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Old 08-29-09, 06:15 PM
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Looks promising. I'll give it a try tomorrow. Thanks for everything. Joe A
 
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Old 08-30-09, 09:16 AM
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i had what sounds like the same problem you have (mine is a snapper thouh-kohler eng).
clean the ground strap mount,inspect cables.& starter solonoid cable connections.
'I' do not think you have a valve clearance problem.
 
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Old 08-30-09, 11:50 PM
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For the sake of keeping it simple, I will state that valve clearances are a very common reason for your problem, in fact, it is recommended maintenance in your owner's manual. Bad connections can cause similar problems and that could be the case here, but in my experience, valve clearance problems are far more common than bad connections.
 
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Old 09-01-09, 12:42 PM
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i have the same problem with my john deere.
if i spin the flywheel (move slowly)with my hand while i hit the key it works.

with a new battery it does not do this.
or with a clean lead wire at the switch (one time it was badly corroded)

so i would suggest looking at the switch connections and the grounds... try to look at the simplest solution first before you start messing with valves.
 
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Old 09-01-09, 01:00 PM
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Originally Posted by cheese View Post
For the sake of keeping it simple, I will state that valve clearances are a very common reason for your problem, in fact, it is recommended maintenance in your owner's manual. Bad connections can cause similar problems and that could be the case here, but in my experience, valve clearance problems are far more common than bad connections.
Now cheese there ya go spreadin all them years of experience around like they was free

No wonder we barely gettin by doin this for a livin


:bad poster:
 
  #11  
Old 09-01-09, 04:12 PM
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To all a thank you. I tried the valve adjustment a couple of times and it seems to be working very nicely. When all this started months ago it was very sporadic. I would start it a dozen times with no problems and then out of the blue it would start acting up. And even taking the battery off the charger made no difference. Sometimes it would start and sometimes not. I noticed that when it didn't want to start, the starter engaged but it did a slight crank and stop. I was leaning toward a dead spot on the flywheel but the starter would have been freewheeling. Crossing my fingers. Thanks JoeA
 
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Old 09-01-09, 07:10 PM
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Originally Posted by printer-man View Post
i have the same problem with my john deere.
if i spin the flywheel (move slowly)with my hand while i hit the key it works.

with a new battery it does not do this.
or with a clean lead wire at the switch (one time it was badly corroded)

so i would suggest looking at the switch connections and the grounds... try to look at the simplest solution first before you start messing with valves.
The thing is, the valves REQUIRE adjustment periodically. It is part of the regular maintenance of the engine. Failure to do this will cause engine problems. So...."messing with the valves" is required... whether it's the easiest thing to do or not, and as mentioned, it is the cause of similar problems most of the time.
 
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Old 09-02-09, 05:51 AM
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fantastic!!!! i`m glad it works, and I learned something.

that`s the last thing i would have thought of, as i have never had to do this on any engine we`ve had. (we`ve had a lot of `em)

that`s why this forum is great, no matter who you are, you can learn from other people`s posts.

I will remember this for trouble shooting in the future.
 
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Old 09-03-09, 01:01 AM
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Great! Glad we could help and thanks for the update!
 
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