wcjcnc: The last few OHV engines I've done still wouldn't crank when I adjusted the
valves to the proper specs. If I adjust them down to just right at zero
lash they crank and run great. If I adjust them to just .004/.006 they
still have too much compression and won't crank. Why is that?
vinnie vinnie: Thanks dude thought it was like that but now I know
mowerman32000: remember because when the engine is not running the compression release
valve is in the open position, you will have to drop the pistion 1/4" past
top dead center or adjusting the intake will be off as much as 0.005
thousands off from where they need to be.
mowerman32000: the ohv briggs intake valves are on the bottom and the exhaust is on top of
smokeing after you worked on the head could be valve cover gasket leaking
which is common if you don't replace the valve cover gasket and leaks on to
the muffler, or if it is coming out of the muffler then it could be leaking
from valve guides blown head gasket or leaking past the rings which means a
rebuild in the future. I/C means it is industrial and commercial built with
a cast iron sleeve in the cylinder.
mowerman32000: the intake valve on single cylinders is located on the bottom and use the
alumin rod the exhaust uses a steel rod
mowerman32000: Bent push rods are a good sign of very poor maintance on the owner, this
means that at one point the valve starts to hang up and isn't as free as it
should be. this could cause bigger problems such as the valve could get
stuck in the compressed position and hit the top of the piston or could
cause seize to the valve guide and push it out of the way resulting in
pushrod failure also. look around the area of the valve spring and check
for any discolored like it got hot this means it may have bigger problems.
mowerman32000: sounded like you have a valve problem fuel spray out of carb when you shut
it done is a sign of valve isues and may have a blown head gasket on the
mowerman32000: Briggs ohv engines have a decompression valve on the intake side this
allows it to drop a small precent of the compression by opening the intake
valve sooner on the compression stroke so the starter can spin the flywheel
up to speed.
mowerman32000: I noticed the oil is black, not good briggs uses a pressed powder matel to
make the cam gear and lobes on the cam, and dirty oil acts like sand paper
and grinds down the lobes causeing it to mess the timing up on the valves
this will make the pushrods after adjusting them to either move later or
not at all.
emmams5: What gaps did you set the tappets at (in mm if possible)?
Bubba Gump: Awesome video. I have save my customers alot of money by doing this simple
adjustment when it is needed
Tom Ferguson: This is a followup to prev comments. I used a dowel to find TDC and a
piecet about 1 inch long broke off in the engine. I needed to adPlease help.
Barry Hargett: Thank You. This Video helped out a whole lot.
ibdalovely1: i would adjust the valves if its a ohv and check the starter it might be
dead you can jump the starter to see if it is it could also be the solenoid
i can post up a vid if you need of how to jump the starter if you need it
ecodirtrider: I want to tell you thanks. I would not have found my broken intake pushrod
ibdalovely1: if you made it to tight it could have done one of a couple things could
have bent the push rod just pull the push rod out and lay it on something
flat if its not bent theirs other problems
ibdalovely1: yes when you adjust them correct with the plug out by hand turn over the
engine and look at the exhaust valve it should move out slightly like 1-2
mm and back in then out to fully open the valve the lobe can wear down and
not open fully causing it to not allow it to crank fast enough or not at
all causing the no start or hard start
ibdalovely1: ok so thats good but probbaly bad at the same time if for some random
reason the cam lobe has wore off it usually takes a lot to do that though
there could be a giant chunk of carbon holding the valve wide open or it
could have dropped the valve the spring should be attached the the valve if
its not thats a whole other issue i would do a compression check if its way
down or not at all i would pull the head the gaskets are around $15-20
worst case you might need some internal engine parts
rich rohan: Thanks for your time.
ibdalovely1: no problem
ibdalovely1: thanks ooh you get it fixed
ibdalovely1: i dont give the sizes on purpose due to differences in engines its my
channel and for the moment this video that i talk to much in has 49132
views and counting thanks for the view though
Tom Ferguson: Thanks for the immediate response. I did what you recommended and the rod
is straight and no other visible signs of wear. Any other suggestions would
be appreciated. Thanks.
nj1639: Excellent! Been through a bunch of vids trying to sort this out and you hit
it right on with the process and the why. Thanks!
ecodirtrider: yes it fired right up
EATZDUST: hey great vid ,I have a yardwork 17 hp briggs motor don't know its an ohv
as its at the cottage 3hrs away ,it does the same thing as yours did but
only maybe a 2 to 3 inch revolution when turning the key to engage the
starter oh ya checked to make sure it wasent the battery ,now motor doesn't
turn at all .does this sound like valve adjustment is needed? don't know if
they have ever been adjusted as I got this tractor when I bought the
cottage ,ran fine 2 wks ago
Steve Lawrie: Excellent vid! Thanks very much for your help. May I tell you that I have
just fixed my lawnmower B&S 12.5 hp OVS engine IN REAL TIME with your video
on the desktop! It now runs really well. This was really important for me
because I am handing over my house and garden to my new buyers in weeks
time and the grass is getting far too long. Once again, I can't thank you
enough for your time and effort in creating your video. Steve, Toulouse,
66mustangdriver1: man i used to build car engines, went to school for it. so used to
hydraulic lifters i didnt realize this. had a husqvarna mower for years
with a 15hp kholer engine, and it had started to get a little finicky to
start but ran great. well my blade clutch locked up so i bought another
mower today for $125. i planned to use it and some parts off mine. well we
got it home and i couldnt start it, same issue. this motor was briggs and
neglected. real dirty. well you just saved me a lot of trouble man
Tom Ferguson: I had what was a compression problem with similar issue as you showed in
your video. I adjusted the valves and it started fine and I ran it in the
garge for a few minutes. The next day I had the same stuborn problem. I
opened it up and tried it again but now the lower rocker arm is not moving
as I rotate the flywheel. I cranked It for a few seconds ant upper valve
was fine, but the lower arm did not move. Any advise? Please help . Thank
robb swearingen: Maybe you should give the tolerances. Not everyone have the resources to
find the valve clearances. You talk too much also...
stanley johnson: sir. good video. But not one time did you tell the feeler gauge setting.
let the people know everthing plz.
ibdalovely1: i did that on purpose because on some mowers are different and you should
go by the manufactures specs but .004 thousands is what i used on both sides
Freeman Townsend: I have adjusted valves twice no luck could there be a lobe broken inside
Tom Ferguson: Thank you. The lower valve which is not moving has the aluminum push rod.
Is it the exhaust or the intake ? I will try the adjustment again and let
you know. Thanks for the help.
ibdalovely1: thanks its a really easy process come look at my other channel im doing
just how tos in it
Ross Johnstone: I have no compression coming from the right side of my B&G 16hp vtwin
motor... think the right side valve is shot.. any suggestions where to
ibdalovely1: thanks for my first comment from France glad it worked for ya
ibdalovely1: ive found that some times the extra bump on the cam for the compression
release gets wore down from use if you adjust the valves correctally and
turn over the motor slowly you should be able to see the valve move
slightly out then in just before it opens all the way if it dos not its
probbaly the cam that needs replaced
ibdalovely1: i havent dug to far into the internals on any motor but i would pull the
head on that side and check dose it run and have spark on that side could
be a stuck valve or if its a ohv a bent pushrod
januaryman169: Nice easy fix. Good job.
ibdalovely1: but at that point you can look around and get a whole mower for the cost of
a some of the parts or a engine ive had 4 of the ohv engines on mowers this
summer and havent payed more then 100 for the whole mower
heavymechanic2: I had a mower guy bust my chops for not setting the valves in my mower, its
seven years old. I explained to him that running premium synthetic oil
controls the heat and wear more effectively, there is no issues with
compression loss. I used to do a lot of L-Head valves that were tight, I
would add .001 to the intake and .002 to the exhaust and never touch them
again. This setting would boost cylinder pressure and allow for wear.
ibdalovely1: good stuff thanks
AViPhotography: Great vid, I had an idea it was easy. Just needed to see it done before I
stripped it down. Cheers.
rollinstone55: I have been all through EVERY step..multipal times still the same symtoms.
Turns out in must be the compression release valve. any tuitorals for this.
montwolfman: Thank you.
ibdalovely1: well you can try to fish it out but i would pull the head if i know
somethings in the head like that its probbaly wedged between the valve and
the head ive never used anything except a philips screw driver to find tdc
but when you have the valve cover off its not needed you just have to
adjust them when the other is fully open i didnot use anything to fine tdc
in the vid
ibdalovely1: sweet good stuff
How to adjust valves on a ohv briggs and stratton engine4.7
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