briggs and stratton 17 hp mower gets stuck on compression

**keystart** · 12:59 PM

my briggs 17hp rider mower flywheel gets stuck on the compression stroke even after ive adjusted the valves to .004 and.006 and i dont know what to do next

**31YTech** · 06-20-12, 03:19 PM #2

Hello keystart,

When you adjusted the valves, Did you position the piston 1/4" down past top dead center compression stroke ?

**keystart** · 06-20-12, 04:48 PM #3

yes and i tested the starter with the spark plug out

**31YTech** · 06-20-12, 05:11 PM #4

Post the model-type AND code numbers off your valve cover please.....

**keystart** · 06-20-12, 06:57 PM #5

model number is 31c7070154 type is e1 and i will find the code tomorrow morning

**cheese** · 06-20-12, 07:39 PM #6

Did this happen all of a sudden or slowly, over time?

**keystart** · 06-20-12, 08:11 PM #7

its been happening for years but i just now got fed up with it

**keystart** · 06-20-12, 08:14 PM #8

it was the first time use out of winter years ago

**cheese** · 06-20-12, 08:23 PM #9

Try adjusting the valves even closer to zero clearance. I think your compression release is worn out or broken. If this is the case, a closer adjustment is about the only thing that may get it going without opening the engine, and is only a temporary band-aid. While you rotate the engine clockwise from the top with the valve cover off, watch the intake valve for a little tiny movement just before the top of the compression stroke. If there is none, it's the compression release, which requires engine removal to repair.

**keystart** · 06-20-12, 08:24 PM #10

if the engine needed taken apart what would need fixed???

**cheese** · 06-20-12, 08:28 PM #11

It would need a cam/lifter kit/set. They run about $90 for the set, plus a crankcase cover gasket for re-assembly. 9 times out of 10, a proper valve adjustment is all that is needed. Are you 100% certain that they are adjusted properly?

**keystart** · 06-20-12, 08:31 PM #12

ill try again tomorrow to see what i can do

**38racing** · 06-20-12, 08:34 PM #13

I just had a friend's intek with that problem and valves were right on spec. Turned out to be a bad main battery ground at the chassis. Not at home so can provide link but I found a very good MTD article on testing for voltage drops that cause slow cranking.
found the article here:
http://service.mtdproducts.com/Train...electrical.pdf

**keystart** · 06-21-12, 08:26 AM #14

for the earlier question the code is 030430ZA

**keystart** · 03:06 PM

i tightend the intake valve sooo far that it had no compression and it diddnt start it just spun freeley

**38racing** · 06-21-12, 03:54 PM #16

may I suggest that you adjust the intake valve back to .003-.005 and with plug out turn the engine by hand in the correct direction and watch the intake valve. As it closes watch for a little hop.

**keystart** · 06-21-12, 06:32 PM #17

i see the hop but when i tightened the intake all the way down to nothing it wouldnt start it just spinns like it is going to but never does

**cheese** · 06-21-12, 07:56 PM #18

If you see the hop, then the compression release is working. You have either valve adjustment problems, starter/voltage/battery problems, or fluid in the cylinder.

**keystart** · 06-22-12, 03:46 PM #19

thanks i tightened the exaust a little and eased off the intake and it started right up the intake valve is way tighter than .003 so do i still need a new cam or is it good???

**cheese** · 06-22-12, 08:52 PM #20

I think your cam is good, you just have some problems getting them adjusted properly. What is the clearance? As long as it is more than zero, it shouldn't hurt anything.

**keystart** · 06-22-12, 09:14 PM #21

i think its less than 1 or 0 but it runs well so willit be ok?

**cheese** · 06-22-12, 09:54 PM #22

If it's that tight, you risk burning the valve.

**keystart** · 06-23-12, 10:09 AM #23

is that a yes then??? or will it need a new valve

**cheese** · 06-23-12, 11:40 AM #24

I can't tell you if it will be ok or not. You're taking a risk with it that tight, and you may or may not burn the valve.

**keystart** · 06-23-12, 05:58 PM #25

ok thankyou ill wait and see how it does ill be getting a new camshaft soon so it should be ok till then

**keystart** · 06-24-12, 05:36 PM #26

what do you mean by "burning the valve"

**cheese** · 06-24-12, 05:41 PM #27

Combustion gasses go past the valve, burning away pieces of the metal until it ruins it and loses compression.

**keystart** · 06-24-12, 05:48 PM #28

o ok will it be ok to leave it how it is for a few weeks until i get a camshaft?

**cheese** · 06-24-12, 05:58 PM #29

There's no way I can know that. Maybe, maybe not. I'm not even convinced you need a cam...

**keystart** · 06-24-12, 06:00 PM #30

then why would i need to adjust it that tight for the compression to release properly

**38racing** · 06-24-12, 07:59 PM #31

did you ever investigate the possibility of a voltage drop problem as per my jun 20 post with the MTD link?

**keystart** · 06-24-12, 08:27 PM #32

i have looked for voltage problems by hooking up a multimeter to my battery and it showed no drop i finally looked at your link because my cpu wasnt cooperating and it told me that i need to hook the multimeter up to the starter is this correct?

**keystart** · 06-24-12, 08:32 PM #33

r u supposed to get any voltage readings at the soulinoid?

**keystart** · 06-24-12, 08:43 PM #34

new prooblem has just arose when it starts it bellows white smoke for about a minute or so dont know if its anything to be concerned about

**cheese** · 06-25-12, 01:24 AM #35

Yes, that is probably directly related to your problem. Fluid in the cylinder. Smell the oil for a gassy smell.

**keystart** · 06-25-12, 07:05 AM #36

yes in fact it does have a sort of irregular gasey smell what does this mean?

**keystart** · 06-25-12, 09:59 AM #37

while testing voltage i found these: two plugs that cant plug into another and one compleatley severed wire

the wires are yellow with red plugs

**cheese** · 06-25-12, 11:16 AM #38

The gassy smell means that your carb is leaking fuel into the cylinder when it's not running. The gas seeps past the rings and gets in the oil, thinning the oil. Then the oil works it's way into the cylinder and it raises the compression too high for the starter to turn the engine (fluid in the cylinder I mentioned earlier). The carb needs repair and the oil changed.

**keystart** · 06-25-12, 12:09 PM #39

where is the carb located?

**keystart** · 06-25-12, 12:48 PM #40

i inspected the carb neetle but it seems ok what next?

briggs and stratton 17 hp mower gets stuck on compression

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