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B&S 16 HP hard turning over

#1

scott181

scott181

16 HP model 313707 hard to turn over. Starter pulled and spins fine under no load.
Removed spark plug and no difference. New battery, fully charged. Even with spark
plug removed can only turn engine by hand about 1/4 to half a turn. No belts connected
either. Drained oil and replaced, making sure not to over fill. Pulled valve cover, they were
wet, but no standing oil. Every now and then it will crank for a few spins and if choke
and throttle are correctly set it fires up, but very very seldom can I get it to turn over
with the starter more then 1/2 to quarter of a turn.
Any help or thoughts would be greatly appreciated.


#2

B

bertsmobile1

Sounds very much like you have overheated the engine and a valve guide has shifted causing coil bind on one of the springs.
Take the rocker cover off and look at the valves.
They should both be at equal heights and move the same amount when the engine s turned over.


#3

T

Tinkerer200

"and a valve guide has shifted causing coil bind on one of the springs."
??

The valve guide should extend 1/8" above the head casting. Much more than this may cause trouble. The valve spring keeper may be hitting a slipped valve guide.

I can send you a Service Manual for your engine IF you like. Address below, put in proper format and remind me engine model number and what you want. I have several fixes for slipped valve guides also.

Walt Conner
wconner5 at frontier dot com


#4

scott181

scott181

Here are a couple of pics I took after removing the rocker cover.
Does this help or do you need a different angle???

Attachments







#5

T

Tinkerer200

I can't tell anything for sure from your pictures, perhaps others can. Does not appear the valve guides are excessively high. I think you are going to have to do the investigating yourself.

Any possibility engine was run low on oil or other wise over heated and metal transfer on the crankshaft is causing difficulty rotating?

Walt Conner


#6

B

bertsmobile1

Watch the rockers move as you turn the engine.
Note exactly what is happening when the engine gets hard to turn.
there are several things that can cause the engine to bind.
if it happens every second revolution at the same place then it is valve or cam related.
if it happens in the same place every revolution then it is crank or fly wheel related.

If the latter then remove the flywheel and check for damage to the stator or debris stuck between the magnets.
If not then it is open heart surgury time.


#7

T

Tinkerer200

"Starter pulled and spins fine under no load."

"Even with spark removed can only turn engine by hand about 1/4 to half a turn"

" Every now and then it will crank for a few spins and if choke and throttle are correctly set it fires up,"

Some confusing statements here. Loose magnet under flywheel is a possibility BUT hard to fit it into these statements.

Walt Conner


#8

scott181

scott181

Sorry if it got confusing, I'll try to answer each one fully on it's own.

Tinkerer200 said:
"Starter pulled and spins fine under no load."
I removed the starter and connected it to the battery with jumper cables. It spins just
fine. No hesitation and a good high speed.

"Even with spark removed can only turn engine by hand about 1/4 to half a turn"
reinstalled starter, removed spark plug so as not to have any compression. can get a turn or so
out of it using starter. when it binds up can not manually rotate the engine.

" Every now and then it will crank for a few spins and if choke and throttle are correctly set it fires up,"
Before it got to this point it was acting like a low battery, spin a couple times kinda slow, but if all
was set correct it would fire up and run. Once running it drove ran fine, just don't shut it off until you
were completely done with the job.

Some confusing statements here. Loose magnet under flywheel is a possibility BUT hard to fit it into these statements.

Walt Conner
Click to expand...

I was asked earlier if it had over heated or ran low on oil. No to both of those questions. Oil was always checked
before starting, and being a riding mower it is only used for a double city lot, not a big acreage type area. I'm starting
to think that open heart surgery will be my only option. Thank you to all for suggestions and comments.


#9

scott181

scott181

bertsmobile1 said:
Watch the rockers move as you turn the engine.
Note exactly what is happening when the engine gets hard to turn.
there are several things that can cause the engine to bind.
if it happens every second revolution at the same place then it is valve or cam related.
if it happens in the same place every revolution then it is crank or fly wheel related.

If the latter then remove the flywheel and check for damage to the stator or debris stuck between the magnets.
If not then it is open heart surgury time.
Click to expand...


It is happening about every revolution. Valves seem to operate fine. I'm gonna
pull the flywheel and take a look. I can actually hear some rubbing type noises
when I turn it by hand around the flywheel. Not a grinding or loud rubbing
noise, but it is there.


#10

scott181

scott181

Here is the update and the problem found. Took the flywheel off, talk about a
pain in the ***. Here is what I found........... Thank you to everyone for all
of your help and suggestions, and I hope this thread will help someone in
the future if they have a similar problem.

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#11

B

bertsmobile1

Flywheels & stators are a lot easier to fix than con rods. counter weight & cams.
Briggs code their stators by changing the plug shape & colour as well as the wires so take you old ones to a breaker to get a replacement.
You can reglue the magnets in but it is not worth the time & effort, thousands of good 2nd hand ones out there.


#12

Boudreaux In Eunice La.

Boudreaux In Eunice La.

Bert is also a carpenter cause he hit that nail on the head for sure..............

Wowee how the heck did that stator get to be like that.......... ??? I think I have a flywheel in stock for your engine and a stator also.......

Let me know the color of the wires......... Mon Ami ~!~!


#13

scott181

scott181

Boudreaux In Eunice La. said:
Bert is also a carpenter cause he hit that nail on the head for sure..............

Wowee how the heck did that stator get to be like that.......... ??? I think I have a flywheel in stock for your engine and a stator also.......

Let me know the color of the wires......... Mon Ami ~!~!
Click to expand...


The stator was cracked on both sides opposite each other, but still tight. I'm thinking
after it cracked it vibrated enough to stick out just enough for the magnets to catch
it and rip it forward. Would also explain all the magnets bunched together on one
side. I'm going to see if I can get them used local here, but just in case what kind
of price for the stator shipped to NY. The wires are red and black, and I can get a
picture of the plug if you need that.


#14

B

bertsmobile1

Need the plug style & colour.
If you google Briggs alternator replacement you should get a link to the guide as a PDF it is all over the place.
Usually what happens is a bit of gravel gets in then it gets stuck between two magnets and that sets the bomb off.
The other biggie is a DIYer dropping one of the tiny guard screws that fell down some where & vanished


#15

scott181

scott181

I got lucky and found the parts local. plugged right in and bolted right up.
Spins just great now. Having another issue with it now. Doesn't want to
start. Looks like good spark, and with a shot of gas in the carb, it tries
to start. Actually while cranking it sounds like it is running at real low low
speed. Have to have the choke out 3/4's of the way, and full throttle. If
you slow the throttle down it doesn't even try, or pull the choke out fully
it doesn't try. Push the choke back in and no. Normally if there is carb
problems, or that pesky needle in the anti backfire, or whatever that is
called, you can get it to fire up and run for a couple seconds with a shot
of gas or starting fluid shot into the carb. Not so this time. When I say it
sounds like running at real low speed it is firing, with exhaust coming out
and getting hot to the touch. I can't imagine any kind of timing issue as it
isn't backfiring or anything like that. Just acts like it is starved for fuel. To
answer the obvious, which I've made these mistakes before, there is gas
in the tank, and I loosened the clamp for the gas line to the carb long
enough to get fuel to drip, so there is gas to the carb. I don't have alot
invested in this thing, so I may just end up scrapping it and getting a
used one to get me by. Once again though I do want to thank everyone
for the suggestions, comments, and help. It's good to have a thread that
isn't full of arguing, name calling, and just plain bashing. This is what this
forum is all about.


#16

B

bertsmobile1

scott181 said:
I got lucky and found the parts local. plugged right in and bolted right up.
Spins just great now. Having another issue with it now. Doesn't want to start. Looks like good spark, and with a shot of gas in the carb, it tries
to start. Actually while cranking it sounds like it is running at real low low speed. Have to have the choke out 3/4's of the way, and full throttle. If
you slow the throttle down it doesn't even try, or pull the choke out fully it doesn't try. Push the choke back in and no. Normally if there is carb
problems, or that pesky needle in the anti backfire, or whatever that is called, you can get it to fire up and run for a couple seconds with a shot
of gas or starting fluid shot into the carb. Not so this time. When I say it sounds like running at real low speed it is firing, with exhaust coming out
and getting hot to the touch. I can't imagine any kind of timing issue as it isn't backfiring or anything like that. Just acts like it is starved for fuel. To
answer the obvious, which I've made these mistakes before, there is gas in the tank, and I loosened the clamp for the gas line to the carb long
enough to get fuel to drip, so there is gas to the carb. I don't have a lot invested in this thing, so I may just end up scrapping it and getting a
used one to get me by. Once again though I do want to thank everyone for the suggestions, comments, and help. It's good to have a thread that
isn't full of arguing, name calling, and just plain bashing. This is what this forum is all about.
Click to expand...

Being that you have just replaced the flywheel chances are the timing key has sheared.
When fitting a second hand flywheel you need to check the taper very carefully as oft there will be a burr on the top or bottome of the hole which prevents the taper from locking when you tighten down the bolt.
Some times I have to grease the under side of the bolt & washer to sop them turning the flywheel as I tighten up.


#17

T

Tinkerer200

"Being that you have just replaced the flywheel chances are the timing key has sheared."

OR the key simply slipped out of place as you sat the flywheel in place. You can check this by removing the screen, adapter, nut and washer and looking down the key way with a flashlight to see it the key ways of both flywheel and crankshaft line up. Torque flywheel to 100 ft. lbs. both surfaces clean and dry.

Walt Conner


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