trying to start old MF35

robreynolds

New User
I went to an auction and bought a MF 35 with a
Continental Z134 engine. The carburetor had a lot
of water damage, so I installed a new one. I put
on a new cap, rotor, distributor dust cover, and
spark plug wires. It has Champion D16 spark
plugs, which are correct according to a cross
reference I found online. A guy at the auction
said that he remembers seeing this tractor run
about 5 years ago, which is when the old man
parked it.

Currently I have a lawnmower gas tank connected
directly to the carburetor just to make sure. I
verified that the firing order is correct and
starts on the correct cylinder. There is a nice
white spark on each spark plug. It cranks but
won't start. I took the intake hose off the
carburetor and stuck my hand in front of it, and
sure enough it is drawing air strongly. Then I
squirted a shot of gasoline directly into each
cylinder through the spark plug hole, and it still
doesn't start.

These tractors are as simple as a bowling ball. I
don't know why it hasn't fired up yet. It
occurred to me that maybe I had the battery
connected backwards, so I unscrewed a plug and
stuck my finger in the hole while holding the
spark plug against the block. Sure enough, it
creates pressure and makes a spark at the top of
the stroke, which verified that it is in fact a
negative ground system, so I've been doing it
right.

But obviously something is still wrong. What's
the next thing you would check?
 
1.Are you sure it is timed right? Easy to get 180 off. Spin slowly while someone hits the starter button, see if it backfires, hits, whatever...
2.All year round, I choke all my Continentals every time they haven't run in the past hour or so.
3. Not just gas, but squirt a little oil in the plug holes, to get compression up.
4. And if that don't work, go buy a can of starting fluid. But I am not suppose to say that on here...
 
battery being hooked to neg. or pos. ground has absolutly nothing to do with it starting.
also you said making spark at top of stroke verifies it is in fact neg. ground. that is totally not so either.
better check for spark at top dead center on the compression stroke. to make sure its timed correctly.
also is the gas getting into the carb? you may have a plugged fuel line or filter.
 
Well if you have fat white spark and you are sure it's getting fuel then it's got to be either timing (valve or ignition or both) or compression although even with low compression you should get some signs of life.

Have you done a compression test? If you get absolutely no compression it could be the valve timing although if it was running when it was parked then nothing should have changed there.........IF it was running.........IF......I've learned that you can't always trust what people say. I much prefer to do my own detective work if you know what I mean.
Check, check and check the timing again, a carelessly placed distributor could cause you a lot of grief.

Oh, and here's something that caught me one time. When looking at the firing order (1,3,4,2) remember that the distributor turns counter clockwise.
 
I have the same tractor and just put in new timing gears. Had the same problem getting it started. When # 1 is on compression the rotter should point at the # 1 cylinder. I also had to put in Champion D 21 plugs.
 
When all else fails, pull start it in 2 High or 3 High. I suspect an overlooked gremlin though.
 
To be clear regarding the battery polarity, I don't know if this starter has field coils or permanent magnets. If the latter, reversed polarity would make the starter spin backwards. Upon further reflection, it would also cause the gear not to engage the flywheel, so that's a moot point. So I know that I have it connected correctly whether it makes a difference or not. At any rate, the engine is making compression, the firing order is 1-3-4-2, the distributor is going counter clockwise, the wires are on the correct plugs, and there is no filter in the fuel line. That's sort of a moot point as well, considering the gasoline that was placed directly into the cylinders. Anyway, it's a brand new carburetor, new fuel line, and a clean 1-quart tank I pulled off a lawnmower.

Here's something I noticed today. I primed the #1 cylinder and replaced the spark plug, then I cranked the engine. It went around maybe 1 revolution and then the starter disengaged from the flywheel and spun by itself. Maybe it got just a little pop out of one cylinder and threw the gear out because it's worn. I thought I smelled just a tiny bit of exhaust.

When my wife and kids get home from their road trip this weekend I'm going to have them help me pull this tractor with the other tractor and see if it will start.
 
I fail to see what pulling to start it will accomplish if it won't start with the starter, other than saving stress on the starter and battey. If it's that difficult to start but will start by pulling it, then it will always be that difficult to start and will need some work.
 
I read somewhere that people used to enjoy reading but the internet is turning us into skimmers who read only the first sentence or two, glance at the middle, and then read the last sentence or two. I'm starting to believe it.

Valves: check
Compression: check
Fuel: check
Firing order: check
Timing: check
Spark: check

Possible clue: Engine spins, then starter disengages, while the slight smell of exhaust (not gasoline) is present.

Next step: Attempt starting by towing to eliminate the factor of possibly worn out or gummy starter parts.

I'm not trying to be unpleasant, but really, this has been a very disjointed conversation. I appreciate your help, and when I get the tractor started I'll let you guys know what happened.
 
Well if all those things check out then it runs!
Clearly that is not the case so at least one of those things is the culprit.
I'm not trying to be a smart a$$ but when all of those things seem to be ok, I start checking things over again, trying different possibilities.
From what you described in your original post you have already done all of the things all of us might do when troubleshooting an engine. I don't think anyone is only reading part of your post, I think when the obvious things don't work then we suggest things that have helped us or others in the past.
 
Simple, pulling will spin the engine much faster than the starter ever would. I have done this many times before and got one running when the starter wouldn't do the job. Agreed that there will probably be another issue with the starter/battery that will need to be addressed but at least you may be able to diagnose what it needs.
 
You're probably right. It probably does run.
Come to think of it, it would probably run
(poorly) even if I had the wires going clockwise,
because 2 of them would be correct, and it would
probably at least fire even if there were up to 3
stuck valves or if the distributor were rotated
several degrees.

I suppose I just had to go through it step by step
and think about it, and now that I have, I recall
that right from the beginning the starter got
kicked out from time to time when I was cranking
the engine. That's the direction I'll go in next,
but it will have to wait until Sunday when my
family comes home. Until then I'm not going to
fool with it any more.
 
And how was the condition of your choke cable? Was it closing at the carb as tight as a rich man"s purse strings? Did it slip out of your fingers as you cranked and cranked for several seconds? Cause if you are already triple checkingthe timing and wires etc, and it kinda fires, but doesn"t smell like gas.... a good choking will get it to smell like gas... or... you aren"t getting gas....
 
Have you checked the initial timing? If you have spark and fuel and the firing order is correct, timing is all that"s left, assuming the engine is in reasonable mechanical condition.
 

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