Auto Compression Release Questions

Rales · #1 06-04-2012, 02:08 PM

My 169 is having some issues starting and I have determined that the Auto Compression Release is not functioning. I pulled the Cam cover and everything appears to be there including the spring. I however tried to move the Auto Compression Release parts but I was unable to get the tab to come out. Each peice has side to side motion but I am unable to spread the parts to enable the ACR. Nothing looks jamed. I believe the spring ok but maybe its not hooked onto the correct parts. If I understand the ACR process the spring should be spreading the peices apart when the engine is off. Right now the spring is hooked to outside of the peices, should it be hooked to the inside instead?

Any ideas or help is greatly appreciated.

Thanks
Dave

David a Calkins · #2 06-04-2012, 07:40 PM

if it were me i would pull the head ,and roll the engine over ,and see where the exhaust is at ,it will be not open if the c/r is now working .the c/r stay open from .030 to .043 ,till the engine is at 6 00 rpm ,and there is a tap on the cam .so you can adjust this if its to low or to high .but with out seeing the spring its hard to tell

Rales · #3 06-04-2012, 08:10 PM

I looked at it again and it appears the spring and weights are working. However I noticed two areas that concern me. First the Tab that pushes on the lifter for the ACR is not parrallel to the cam but rather angled down. I am curious if this has bent and thus not giving the release it should. I have a spare 10 and 12 hp engine laying around so I will pull the came cover and take a look at them if someone else doenst reply. The second is that when the exhaust lobe is away from the lifter there is some considerable play in the lifter.

I plan to check my valve lash tomorrow and see if maybe thats just way out of spec. Once it starts it runs fine with plenty of power.

David, thanks for the information, i was going to pull the head but on the 16hp the spark plug is directly over the exhaust valve, I pulled the spark plug and took a long wooden Kabob stick and put it down the spark plug hole and rested it on the exhaust valve. I only seeing it moving the full stroke, and does not lift the little bit for the ACR. This has led me to believe that somewhere something is wrong that is not allowing the ACR to release the pressure.

Diz Jr. · #4 06-04-2012, 08:52 PM

I would definitely check the valve lash first.
My 169 was the same way when i got it. I had to bend the tab just a smidge to get it to lift. You have to be careful, the manual i was looking at says you can't bend the tab or it will break. I figured it wasn't working anyway so i tried it and it worked. Just my

David a Calkins · #5 06-05-2012, 06:24 PM

be fore you check for exhaust .017 -.019 roll the engine back words ,to set exhaust ,because the c/r will come up and give you a bad reading .you should be hearing it tick alot if you have to muck clearance .David

Rales · #6 06-07-2012, 10:33 AM

David, thanks for the information, one thing I do not hear is the compression release clicking at all. Could that be a weak CR Spring? Also the engine does not sound loud so I assume the valves are within spec but I have not gotten around to verifying yet. Hopefully today.

David a Calkins · #7 06-07-2012, 03:54 PM

if you dont hear the clicking ,thats good ,clicking is because ,the spring is bad ,letting the weights fall to easy ,the weights should stay in place till the engine hits 600 rpm ,what did you come up with ,when you checked the exhaust valve clearance

Rales · #8 06-07-2012, 10:11 PM

I was able to check the valves today, exhaust was .024 and intake was .014. I got them adjusted to the correct exhaust .017 and intake .008. I was able to get the starter to turn over the motor with ease now so the ACR is actually working, the valves were just too sloppy.

Thanks for the help guys, its greatly appreciated. Now I just have to order the gaskets for the breather, carb, and cam cover. I guess I should also fix my sloppy throttle.