14.5 ohv briggs(adjusted valves, binding(?) before compression. Help!)

[danleeson]

She was hard to start, adjusted the valves, ran ok, then same prob, take the plug out and she would turn over fine, although did seem to hesitate before tdc. Ran ok but was losing oil, traced it to carb from blowby(?) Any help would be appreciated.



Seems to point to cam shaft compression release, Ill tear it down this weekend. (Unless someone thinks it may be something else.)

 

[ILENGINE]

Reconfirm the valve clearance are in speck. If that checks out then most likely the compression release in messing up.

 

[danleeson]

Intake is within specs, so is exhaust. Checked roughly 1/4 inch or so past tdc.

 

[ILENGINE]

While you have the valve cover off, remove the spark plug and then turn the engine over by hand and watch the valves. If the ACR is working you should see it bump one of the valves off its seat right before TDC compression.

You will have to reset the valves after replacing the camshaft if that is what is wrong.

 

[danleeson]

There was no perceivable release on either valve. Ordering a new cam shaft, might reseat the valves and general clean up while
I"m in there. Thank you for your time.

 

[SeniorCitizen]

Rather than attempting to eyeball the release bump, as the piston approaches TDC on the compression stroke a 0.001" - 2 or 0.003" feeler gauge should get tight at the bump spot and release feeler gauge shortly after.

 

[DaveTN]

I've had problems with various OHV engines due to ACR (Compression Release)
mechanisms not working well or not at all. I've heard IL ENGINE remark about
having a multitude of problems over the years with B&S doing that same thing.
Kohler isn't far behind imo! I've also heard of twin B&S wearing down cam lobes,
especially the one closest to the Cam Gear. I believe it was poor quality metal
being used. I miss the old valve-in-block engines of the old days.

 

[ILENGINE]

Dave, I will make a point to adjust the valves a couple times to make sure they are where they are suppose to be, and turn it over by hand a few times to make sure the compression release is working. I will then start the engine and run it for a few minutes, and do a few restarts. If it acts up the camshaft gets replaced. I have seen some work when cold, but wouldn't work when warm. I have also found the flyweight in the bottom of the sump more than once.

The lobes on the camshafts are made of sintered metal or compressed powdered metal. some of them have a hardening issue.

I don't see a lot of the courage camshaft issue, but most of my customers with kohlers have the command engines. A have a few with the new 7000 series but no problems so far with those. The thing with Kohler is they recommend if you change on gear, you should replace all the gears, which would require replacing the governor, camshaft, oil pump, and crankshaft. There goes the price of a new engine.

 

[bertsmobile1]

Once again. it is the magic pudding syndrome.
No use bitching about it.
A real steel cam for a single cylinder motorcycle costs anything up to a grand.
I pay $60 / lobe just to get them ground.
And we expect "technology advances" to allow us to buy complete engines for that price. Then bitch if there is a delivery fee.
There is a rason why commercial & horizontal shaft engines cost 2 to 3 times a vertical shaft mower engine.
If "joe public" was willing to pay for quality we would still be getting quality.
But joe public is greedy ,selfish & mean and wants every thing and they want it for free.