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2010 craftsman 21hp wont crank more than 1 rev.

#1

E

EVT123

My 2010 craftsman with a 21 hp briggs will only crank 1 revolution then stop, I can manually turn it past that point then it will crank 1 more rev. starting system checks out, I adjusted the valves - no improvement. I have been told it could be an internal compression release on the cam - does this sound accurate and or common? if so is it worth repairing?
Thanks


#2

gfp55

gfp55

EVT123 said:
My 2010 craftsman with a 21 hp briggs will only crank 1 revolution then stop, I can manually turn it past that point then it will crank 1 more rev. starting system checks out, I adjusted the valves - no improvement. I have been told it could be an internal compression release on the cam - does this sound accurate and or common? if so is it worth repairing?
Thanks
Click to expand...
Yes that is accurate and it is a common problem and I think it is worth repairing.


#3

E

EVT123

Thanks for your input - I will investigate the cost further.


#4

R

Rivets

Check your oil level, if it is right on the line, pull the plug and see if it will spin over properly. If it is over filled smell the dipstick. If it smells like gas, your float needle in the carb and the crankcase is now filled with a fuel/oil mixture. You will have to drain the oil and have the carb rebuilt.


#5

primerbulb120

primerbulb120

I have had this same problem on a Cub Cadet LT1050, and it turned out that the battery was actually too small. This may not be your problem, but check the battery and connections to make sure they are large enough and in good condition.

PS: If you own a boat with a trolling motor, try disconnecting the existing battery and hooking the mower up to your trolling motor battery.


#6

E

EVT123

thanks , I will check that.


#7

H

hrdman2luv

EVT123 said:
My 2010 craftsman with a 21 hp briggs will only crank 1 revolution then stop, I can manually turn it past that point then it will crank 1 more rev. starting system checks out, I adjusted the valves - no improvement. I have been told it could be an internal compression release on the cam - does this sound accurate and or common? if so is it worth repairing?
Thanks
Click to expand...

Does it turn over normally with the spark plug out of it?


#8

E

EVT123

Yes it will turn over without the plug in it.


#9

pugaltitude

pugaltitude

If you checked valve clearances then it does sound like a decomp problem but better check easy things 1st.

Do Rivets check 1st as its quick and easy.

What engine? Assume model 31 briggs single cyl.
What did you set valve clearances too?
How did you do it?
You have to have piston 1/4 inch past tdc on power stroke.
Servicing Engine Valves | Mower & Small Engine Repair | Briggs & Stratton FAQ

Use this link and some you tube videos.
Also check electrical connections and make sure battery is good.


#10

H

hrdman2luv

EVT123 said:
Yes it will turn over without the plug in it.
Click to expand...

Then I'd re-adjust the valves. Maybe you didn't turn the crank to the right position.


#11

T

trunkbuster

I'm having the same trouble with my 31 series engine, it won't crank past compression. I've adjusted the valves to the recommended clearance while the piston was at 1/4 past TDC and also at TDC so I believe it's the compression release. The battery is good, I've tried two. It spins over just fine with the plug out and the oil level is ok. There is no gas in the oil. I couldn't find any posts on how to correct this problem. Does anyone have any experience correcting this issue?


#12

H

hrdman2luv

trunkbuster said:
I'm having the same trouble with my 31 series engine, it won't crank past compression. I've adjusted the valves to the recommended clearance while the piston was at 1/4 past TDC and also at TDC so I believe it's the compression release. The battery is good, I've tried two. It spins over just fine with the plug out and the oil level is ok. There is no gas in the oil. I couldn't find any posts on how to correct this problem. Does anyone have any experience correcting this issue?
Click to expand...

It almost has to be the valves or the starter. Those are the only two ways (that I can think of) that would restrict the engine from turning over with the spark plugs still in. When one is out, there's no compression, and the starter turns the the flywheel freely.
I'd double check the valves/ Make sure you have the "top dead center" correct.

Your starter could be weak. But I'd bet it's the valves.


#13

I

ILENGINE

When you are turning the engine over by hand and watching the valves open and close, do you see one of the valves bump off just before TDC.


#14

M

mechanic mark

Post model xxxxxx, type xxxx, trim xx from engine. How did you adjust valves, procedure?


#15

H

hrdman2luv

ILENGINE said:
When you are turning the engine over by hand and watching the valves open and close, do you see one of the valves bump off just before TDC.
Click to expand...

I just stick a screw driver into the spark plug hole, and gently turn the flywheel around a few times to make sure the valve I'm adjusting is where it's supposed to be, and the piston is all the way up...
Then after I've done that to both valves, I recheck them to make sure I didn't make a mistake.


#16

S

SeniorCitizen

The compression relief cam bump can be checked with one of the least expensive tools on earth you already paid for and have. It's that feeler gauge set you set the valves with. If the cam bumps the valve as it should the 0.001 or 0.002 feeler gauge will tighten just before TDC. If the cam is shot the clearance you set ( 0.004 - 0.006 etc. ) will still be there through the compression stroke. Or you can go expensive and check the cam bump with a dial indicator.


#17

M

mechanic mark

hrdman2luv said:
I just stick a screw driver into the spark plug hole, and gently turn the flywheel around a few times to make sure the valve I'm adjusting is where it's supposed to be, and the piston is all the way up...
Then after I've done that to both valves, I recheck them to make sure I didn't make a mistake.
Click to expand...
Post craftsman model number from under seat. Did you adjust intake & exhaust valves before rotating engine?


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