The Old man got a 2 Stroke Lawn mower from his friend.
It is a Victa Pace Model PAS201G.
It has no Decompressor installed. There is no hole for a Decompressor at all.
The Lawnmower seems to have been taken to a repair shop that said it is not repairable. (Compression???)
The first thing I noticed was it has the white carby cover on 90 degrees from horizontal. Easy fix anyway.
It had its pull cord mechanism pulled off, so I could see the Piston rod. The whole area was pretty clean, so it doesn't seem to have sucked in any dirt.
I decided to put it together and see what its compression was.
Since it has no decompressor there was no need to plug the hole with a Spark Plug.
After pulling the Cord 5 times, the Gauge reaches 60 PSI.
It isn't 80-100 PSI but better than 35 PSI I get from the old motor.
My question is do I proceed overhauling the Carby and installing the Float Lever and testing.
I know Maxwestern mentioned no lower than 50 PSI.
Or do I wait to find another lawn mower with a better compression.
Most Compression testers aren't accurate ,50 psi is the lowest I'd use with my comp tester as I know the real reading will be at least 65 psi and have used mowers like this for 10 years and haven't had a problem.
here is a video showing how far out different comp testers can be.
I'd go and fix the carby and use the engine with the higher comp.
You can run a mower on 65 psi ,below is a LawnBoy motor spec that has minimum 65 psi cold.
If the Schrader valve isn't at the spark plug end on the compression tester the flexible hose just adds to the compression chamber volume ,thus giving a lower reading.
Harry, If you are going to start this motor make sure it has a blade carrier on it because without it it will give you a severe kickback, hurting your fingers
Harry, If you are going to start this motor make sure it has a blade carrier on it because without it it will give you a severe kickback, hurting your fingers
Hi NormK,
Thanks for the advice. The aim is to fix it on the current base and then when I am sure it is working remove the motor and install it on the other base.
Just a reply about the Video on the different comp testers ,I can't believe how much of a difference he got with the 2 readings,I suspect the o ring was leaking on the cheaper red box tester as he said he only tightens them finger tight so it could have come loose or compression leaked past the o ring as I've had the o rings leak compression before on testers unless I tighten the plug hole fitting with a socket so it's tight.
When I tighten the tester tight in the threaded hole the O ring eventually fails and needs to be replaced but now I have just installed a spark plug washer on my comp tester threaded connector.and that should last for ever.
The longer the flexible hose the more your reading will be down from the correct reading if the Schrader valve isn't at the spark plug end on the compression tester with small engines.
I checked a Victa 2 stroke 160 cc motor ,the short comp tester has the Schrader valve at the end that goes into the head of the motor and the longer tester has the Schrader valve up the other end near the gauge.
I get a reading that is 20 psi different with the two comp testers (longer tester is 60 psi ,short tester is 80 psi)
I usually like a small motor to be on at least 50 psi with the longer tester so that may be 70psi for a cold reading and is the lowest I will use a mower ,I find the mowers can still last 10 years but can stall a little easier in long grass,they will start straight away after stalling hot but find any lower comp reading and they can be a pain to start hot after stalling in longer grass , most people prefer at least 85 psi as a lowest compression reading.
The short tester may be a little low reading also because you are still making the combustion chamber bigger with this tester than if you had a spark plug installed.
My Chinese made Compression Tester does have a Schrader Valve at the bottom of the hose, but as usual it does seem to leak when you are blow in the hose. So you get what you pay for.
Sunday Update,
After getting 60 PSI cold , I cleaned the motor and installed the Float Lever, pulled apart the carby and checked it all and put it all together. After endeavoring to get the throttle cable to work properly. It seems to work now. You can go half way, it finds a bump and when you push a little bit more it clanks and goes to full throttle.
So
After priming a few times and pulling the cord a few times it started. It smoked around the exhaust and settled after a while. I run it for a little bit and turned it off.
After having it off for a few minutes, I decided to start it again. Unfortunately this time it did not start. I pulled out the Spark Plug and tried to check Compression. Well would you believe it compression when hot is 45 PSI. 5-10 minutes later it reads 55 PSI. 5 -10 minutes after that it got back to 60 PSI.
Unfortunately this motor seems to also have a Compression issue too.
I did adjust the Poppet Valve back to A, I found it about halfway between A and C. Would this affect the restart when hot. ( Poppet has 4 A C)
Any advice
I'll need to keep looking for a Hard Rubbish 2 Stroke Motor.
Yes I've had the same problem when the motors are below 70 psi cold with an accurate comp tester (sounds like your tester is accurate with the Schrader Valve at the bottom of the hose,) They are hard to start hot when the compression is down..
If the tester is slowly loosing pressure after a test you may be able to replace the Schrader Valve to fix it.(it should screw in)
The carby poppet should be set to C but this setting won't effect starting it's more a long term setting so it's not too rich or too lean.
The two choices would be, one look for another (engine / mower ) or two just put some new piston rings into this motor that is on 60 psi cold.
If you replace the rings you will need to make a tool to get the conrod / piston out. (just cut an old socket up)
Yes Norm it would be better, but I didn't mention one because if you are only repairing one engine and a hone is about $20. plus new rings and a head gasket ,it could be a better option to buy a used mower .
Harry mentioned the motor looked clean with the starter off and if the bore looks good, I've fitted rings without a hone and they bed in after a while.
I think you can get away without a hone if the wear is minimal; often, simply replacing the rings with proper break-in procedures is sufficient for most situations.
I never Hone a Briggs with alloy bore.
If the bore looks ok sometimes I don't like to hone the bore as the piston is already close to it's maximum bore clearance so I don't want to give it any more clearance from a hone.
When I do use a hone I put 1200 wet and dry around the stones so the very minimum is removed.
When I was cleaning everything and installing it back together I noticed the vacuum control button fitted on the motor housing, that has a hose connected to it and the Carby Cap has no hole on it. The other faulty motor definitely has a hole on it and thought it was strange.
Is this the reason why it seems to clank to Full throttle as there is no air pressure at the top of the Diaphragm. I tried starting it on cold position and it wouldn't start, i pushed the throttle forward just before it clanks to full throttle and tried again, It tried to start and once I push it over the clank to full throttle it started.
Throttle Cable is smooth, no kinks in it. I have tried it without the Red Spring and Carby Cap and it does not jam at all. It seems only when the Spring & Cap are on.
The carby diaphragm cap should have a vacuum line connector on it .
With the throttle cable sticking or jamming ,I usually just bend the cable to stop that ,see pic below in the red circle, that is what the end of the cable that goes into the carby looks like after it's bent to stop it sticking.
I have not bent the throttle cable as mentioned by Max.
I still have the original vacuum control button without a hole that is fitted on the motor housing and is connected to the Diaphragm Carby Cap vacuum line connector still on.
I tried starting it on cold position and it wouldn't start, i pushed the throttle forward just before it clanks to full throttle and tried again, It tried to start and once I push it over the clank to full throttle and pulled the cord it started.
So it seems to like to start in the run position only.
Does having a Vacuum Control Button without a hole effect the way it starts.
Secondly
Also I ran the lawn mower for 1/2 hour and tested its RPM and Compression. RPM was 3660 RPM and Compression was about 60 PSI.
I tried to restart the Lawn Mower on Run and it started after the Second Pull.
This time I ran it for another 20 minutes and its RPM was about 3820 RPM and Compression was about 55 PSI.
Again I started the Lawn Mower on Run and it started after the Second Pull.
This time I ran it for another 30 Minutes and its RPM was about 3660 RPM and compression was about 53 PSI.
At the moment my lawns are very dry and its a dust bowl. (The lawn mower is covered with dust).
So having a Vacuum Control Button without a hole affect the way it starts, and does the above RPM and Compression readings , still warrant a Piston Ring Replacement. I am happy to do it , if it will help compression & starting. Also to replace the Vacuum Control Button with one with a hole.
