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fuel problem


twainman's Avatar
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02-02-02, 07:35 AM   #1  
twainman
fuel problem

while motor is running steady fuel drip out of throat of carb i have replaced neddle valve and seat float checks out fine along with level would like to check for blocked air intake but do not know where it is located in carb?

 
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Fisher's Avatar
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02-02-02, 07:55 AM   #2  
Fisher
How did you replace the seat? Is the fuel tank located
above the engine, or does it have a fuel pump to it? Does
it leak while the engine is running or not running, or both?
It is possible you damaged the seat while replacing it, as they
have a special tool for that .
Fish

 
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02-02-02, 06:53 PM   #3  
Hello: twainman

Kindly use the REPLY button each time you want to post any additional information or ask a new question on this topic.

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02-03-02, 06:44 AM   #4  
twainman
fuel problem

i hooked up gas tank above existing tank and conected directly to carb.no gas leak while motor not running same problem while running.

 
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02-03-02, 07:33 AM   #5  
Fisher
You said you had put new rings in. Why? Compression?
Could it be a leaky intake valve sending compression back
through the intake causing fuel to be blown out? That
would be my next guess.
Fish

 
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02-04-02, 05:29 AM   #6  
twainman
fuel problem

i have checked out motor and found problem to be blow back through the intake valve.i think this is it because during power stroke intake valve does not completey close until piston is at top of cylinder.is there any way to adjust valves?

 
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02-04-02, 07:34 AM   #7  
Fisher
You need to find Top dead center between the compression
stroke and the power stroke to check your valve clearances, it
sounds like you are looking at TDC between the exhaust stroke
and the intake, or else your timing it off. Since you have had the engine torn down for a ring job, the possibility of having the
valve or ignition timing off is possible, as shearing a key from
insufficient torque on the flywheel nut is common, and having
the cam/crank gears off a tooth is possible too. But I was thinking
a leaky valve might be the culprit, which would require special
tools to repair correctly. Also the valve stems must be ground to adjust on these engines.
Fish

 
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02-09-02, 08:20 AM   #8  
twainman
fuel problem

i have checked key on fly wheel and thats ok have not gone back in crank case to check timing marks because i did not remove crank or cam shaft when i replaced rings.motor was bought new so was first time apart.i did find intake valve to be burned and grooved.i have replaced with new valve and set clearance to .005 while piston is at top dead center between compression and power stroke.before i finish putting rest of motor together i wanted to ask if it is normal when piston is coming up on compression stroke and intake valve apears to be closed for there still to be a .006 gap between intake valve and seat.does not seem right?

 
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02-09-02, 09:25 AM   #9  
Fisher
Do you mean a .006 gap between the stem{tip} of the
valve and the tappet? The seat is where the beveled lip
of the valve seals, it is a hardened ring inserted in the
block. If you have a gap there, then your problems are
major, it indicates a severely warped block, and seat
replacement may not even be possible. However it
would have been best to have the seat recut when the
new valve was installed, which takes special tools.
Let us know.
Fish

 
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02-09-02, 10:49 AM   #10  
twainman
fuel problem

.oo6 gap is between seat on block and valve. would have reworked seat in block but appears to have no signs of wear or damange.valve does not completly seat until piston is at top of compression stroke.also checked valve seat to block with spring off of valve and seat of valve to top of block is tight .001 will not go and clearance between valve tip and tappet at top dead center is .005

 
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02-09-02, 12:15 PM   #11  
Fisher
When you rotate the fly wheel, it comes to Top center twice.
If you are reading the end gap on the stroke between
when the ex valve and intake are opening and closing,
you need to rotate the engine 1 more revolution to take your
valve stem/tappet clearance measurements.
Fish

 
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02-09-02, 02:47 PM   #12  
twainman
fuel problem

rotated stroke to next top dead center now both valves are open ex is open .008 between valve and seat in block and intake is open .030+.i am complety baffeled.

 
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02-09-02, 04:00 PM   #13  
Fisher
OK. Then if you rotate it back 1 full revolution and you still
have a gap between the valve face and seat, the the
warpage is excessive, probably past the point of repair.
The last time I dealt with an engine that was this bas, only the
exaust valve seat was replaceable, as Briggs did not have
a replacement for the intake. A machine shop may be able to help
you, but probably at high cost, then the option of a shortblock
becomes more realistic.
Fish

 
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02-09-02, 05:14 PM   #14  
twainman
fuel problem

fortunately i am a machinist and can probably repair problem but i don't know where the warpage is or what needs to be realinged?

 
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02-09-02, 05:43 PM   #15  
Fisher
The seat should be perpendicular to the valve guide, so the
valve face seals on the seat's bevel.

 
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02-10-02, 06:57 AM   #16  
twainman
fuel problem

i did not check properly valve seat and gap last night while motor is turning backwards.valve gap and seat are correct while turning backwards.seem's like flat spot on cam at top dead center while running foward.looks like if i set valve stem gap to tappet to .015 instead of .005 it compensate for flat spot,but how bad will this effect motors performance.

 
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02-10-02, 07:13 AM   #17  
Fisher
Post your engine's model numbers again so I can see if it
is the compression release you are describing.
Fish

 
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02-10-02, 07:57 AM   #18  
twainman
fuel problem

model#226437 type 0045 01

 
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02-10-02, 07:41 PM   #19  
mikejmerritt
Valve Lash Info.....

Check lash at TDC after the intake valve closes. Specs call for intake- .005-.007, exaust-.009-.011. I set them at .006 and .010. They'll settle in around .007 & .011. If you run it at .015 it'll beat the lifter and/or valve stem to pieces shortly. The gaps you are finding at TDC on the other stroke are the notorious small engine easy spin compression release to make the engine easier to pull and is normal.

 
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02-10-02, 07:41 PM   #20  
mikejmerritt
Valve Lash Info.....

Check lash at TDC after the intake valve closes. Specs call for intake- .005-.007, exaust-.009-.011. I set them at .006 and .010. They'll settle in around .007 & .011. If you run it at .015 it'll beat the lifter and/or valve stem to pieces shortly. The gaps you are finding at TDC on the other stroke are the notorious small engine easy spin compression release to make the engine easier to pull and is normal....Mike

 
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02-11-02, 09:25 AM   #21  
twainman
fuel problem

set valve stem gap to .006 finished putting motor back together.motor runs great,no more gas drip.Thank you to everyone at doit yourself.com for your input and patience.Sincerly twainman

 
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