MF135 Petrol Engine problems

[OzMF135]

I bought an old 1967 MF135 at the beginning of this year (2016)
It is a 4 cyl petrol engine.
Whilst it is very well worn, it ran quite well for 7 or 8 months.
It had oil and filters changed. New plugs, points, condenser, distributor cap & leads, rotor arm.
I have fitted a new ROP, new exhaust muffler.
For no apparent reason, the engine has developed a heavy backfire.
So I thought it required the timing rechecked etc.
so, here is where my problems begin......
Looking for the flywheel access hole to locate the TDC marks etc.... There is no inspection hole.
I'm advised that it should be on the left side of the tractor engine (when viewed sat on it)
Just below the starter motor on the bell housing.... !!!
There is nothing there.
Any help please ?

Also, I took off the zenith 28G carburettor and have checked it over and cleared all jets out and renewed the gaskets etc....
But underneath the carb body there is a hole into the bottom of the throttle chamber from atmosphere.
Obviously this is sucking extra air into the throttle chamber as well as from the air cleaner etc....

Can anyone help with their thoughts please...

 

[Jerry/MT]

View attachment 489877
I bought an old 1967 MF135 at the beginning of this year (2016)
It is a 4 cyl petrol engine.
Whilst it is very well worn, it ran quite well for 7 or 8 months.
It had oil and filters changed. New plugs, points, condenser, distributor cap & leads, rotor arm.
I have fitted a new ROP, new exhaust muffler.
For no apparent reason, the engine has developed a heavy backfire.
So I thought it required the timing rechecked etc.
so, here is where my problems begin......
Looking for the flywheel access hole to locate the TDC marks etc.... There is no inspection hole.
I'm advised that it should be on the left side of the tractor engine (when viewed sat on it)
Just below the starter motor on the bell housing.... !!!
There is nothing there.
Any help please ?

Also, I took off the zenith 28G carburettor and have checked it over and cleared all jets out and renewed the gaskets etc....
But underneath the carb body there is a hole into the bottom of the throttle chamber from atmosphere.
Obviously this is sucking extra air into the throttle chamber as well as from the air cleaner etc....
View attachment 489878View attachment 489879
Can anyone help with their thoughts please...

Back firing can be caused by retarded timing ( either via improper initial timing, by worn distributor shaft bushings, failure of the centrifugal advance to function properly, etc) or by excessively lean fuel/air ratios ( leaking air downstream of the carb metering section via a leaky carb to manifold gasket, leaking head to manifold gasket, rusted or burned intake manifold, or misadjusted or clogged fuel metering jet).

What engine does your tractor have? Since you state it is a four cylinder, I presume it's a Continental Z series. What was the result of your timing check? Did you check the centrifugal advance mechanism ? The flywheel timing mark viewing port on the Continentals is below the starter assembly on the engine aft flange that the transmission bell housing bolts to.


"...underneath the carb body there is a hole into the bottom of the throttle chamber...." I believe the hole you are referring to is in the carb inlet where the choke is located and thus does not directly effect the carb fuel metering. It can however be a source of dirt. In some carbs, it is generally plugged with a piece of sintered metal and serves as a drain when the carb is "flooded " by over choking. I'm not familiar with the Zenith carbs so this is a guess on my part.

 

[OzMF135]

Hi Jerry/MT
I'm led to believe the engine is a continental. 4cyl petrol. What differentiates the 2 continental engines. How do I establish which model mine is ?
Timing marks appear to be non existent.
What workshop manual is best to acquire ?

 

[Jerry/MT]

Hi Jerry/MT
I'm led to believe the engine is a continental. 4cyl petrol. What differentiates the 2 continental engines. How do I establish which model mine is ?
Timing marks appear to be non existent.
What workshop manual is best to acquire ?

The two Continentals I am familiar with are the Z120 used on the Ferguson TO- and TE-20 (TE- uses Lucas electrics, TO- uses Delco electrics) the Z129 that's used on the Ferguson TO-30. I believe there is a Z134 used on the Ferguson TO-35 and I believe there is a Z145 used on the Ferguson 40.

Your engine should have a data plate on the left hand side in the middle (fore and aft) and right below the head to block split line. It maybe covered by paint and grime and that's the surest way to tell. If I were to guess, I'd guess it was a Z134. Differences include displacement ( the number after the Z is the nominal displacement in cubic inches) oil filter placement,compression ratios, valve sizes, system installations, etc.
The data a plate is your best way to know what you have.

Look on ebay for a OEM shop manual for your tractor. There will be a section on the engines in your MF135 in that manual. It's a good investment if your are going to work on your 135. You can also find one on Yesterday's Tractors web site. Make sure they are the OEM shop manuals and not the IT shop manuals. The IT are not detailed enough and do not cover all the tractor systems.

 

[OzMF135]

Thank you M8
I will look ��

 

[Jerry/MT]

Thank you M8
I will look ��

Here's another piece of info. Apparently through its production life there were a bunch of gas engines for the MF135, both Perkins 3 cylinders and Continental 4 cylinders.

TractorData.com Massey Ferguson 135 tractor engine information

 

[The kid]

Also check your plug wires to make sure one has not failed or corroded. Hello Jerry. It's been a while.

 

[OzMF135]

Thanks for that.
Plug wires etc are all good.

 

[Jerry/MT]

Also check your plug wires to make sure one has not failed or corroded. Hello Jerry. It's been a while.

yeah Kid. I've been pretty busy with other stuff this fall. Good to hear from you.

 

[The kid]

There should be a hole to view the timing mark on the flywheel on the lower left side behind your left foot when seated. It least that where it was on my Z145. You could always use the old school method to find TDC with number one cylinder when it reaches the top.