1944 ZTU Runs... But Hunts

Ken Christopherson

Well-known Member
Hello all! Well, got the FMJ magneto installed on the '44 ZTU today (picked it up from Rudy Calin at rebuiltmags). After figuring out which
way was which on the throttle lever (back is idle, forward is increased RPM), I did get it started. Seems to hunt pretty significantly, and
am unsure as to whether or not this would be a governor issue or carb issue... I figured I would come here to pick your brains. I also
cleaned and rebuilt the carburetor while I was waiting for a magneto.

Guess I am not sure where to start - had to stop working on it today, but I figured I would check valve tappet clearances next time I am at
it just to make sure they are within spec.

Any help is greatly appreciated (and a video is currently being uploaded on YouTube showing the tractor running).
 
(quoted from post at 18:28:10 03/06/18) Video below:
1944 MM ZTU First Run

Neat video. Rudy does nice work my 37 starts in two lifts of the crank when cold and one when warm after his work, carb work and valve adjustments. Try not to crank on the down stroke like in your video if she kicks for some reason it wouldn’t be good. For the lope I would check out the governor for excessive play and slop. These old Z’s are fun to mess around with watching your first start up was cool.
 
I'll have to check it out. I know very little about the MM systems. I have been a Case/JD/Farmall guy my whole life, but wanted to do
something different. This is definitely new to me!

I am also going to replace the plug wires. I should have done that anyhow, but now definitely will.
 
(quoted from post at 19:30:35 03/06/18) I'll have to check it out. I know very little about the MM systems. I have been a Case/JD/Farmall guy my whole life, but wanted to do
something different. This is definitely new to me!

I am also going to replace the plug wires. I should have done that anyhow, but now definitely will.

For sure. When Rudy did my mag I had him build a wire set.
 
your only running on 2 cyl's. firing order is 1342 so you might have wires in opposite rotation on mag. should have oiled down the valve guides too lots of rust in there. even oil the cyl's too before start up is a good thing to do when engine has sat for years. get it running properly before getting concerned about governor.
 
I think I cranked it plenty to get the oil moving through the engine... I must have cranked for a half hour before it started! I will double check the wires - but I am pretty sure I need to replace them. They may very well be original. Also, I think the hunting issue may be the idle circuit in the carburetor having an issue. After doing a little research, this seems a typical problem (governor hunting) when the idle circuit is plugged up.

Thanks!
 
its pretty much standard procedure to remove plugs and squirt oil in cyl's before startup on a sitting engine, also allows for more compression for starting. cranking will not lube cyl's. you can remove plug wires from plugs one at a time and check the spark while running. spark should be jumping 1/2 " gap and be blue and snapping. plus once it is warm from running , i would check compression to eliminate valve problems .
 
i meant to say that point gap and timing must be set first to spec's. the carburator is adjusted last. you will not get a carb adjusted properly on an engine not firing correctly on all four cyl's.
 
Also when you check your carb to gov link. have the throttle in the just off of idle position, Not with gov spring pressure like you did in the video. Lift the gov arm lightly with one finger all the way and feel that there is no hard spots, when it gets to the top it should drop freely. Any resistance will cause the gov to hunt.You may have to loosen the carb bolts rotate csrb one way or the other to find the right spot. Also if the rod is too long or too short can cause hunting. In that case the rod has to be bent to correct, and that can be fun to shape to get free travel after you start bending and still maintain the correct length. When the carb shaft is wide open and the gov arm is all the way up the rod should just fit the holes. Better to be a tad on the long rather on the short. Note also if you insert one end and then the other, the swing of the arc will change the movement of the other arm. IS THIS ALL CLEAR AS MUD???
MMDEL
 
You know that idle screw is really an air bleed, right? you unscrew to LEAN the fuel mix. Try screwing it in 1/2 turn or so.

Also, there sometimes is an internal play problem with the governor. MM offered bakelite shims for the shaft end play. End play on the shaft that runs on the cam gear and also play in the pins in the flyweights can cause problems. Also sometimes the bushing is worn on the shaft with the throttle link arm. And I have also seen a badly worn pocket where the flyweight ball pushes against it.
 
Thank you for all of the info! I probably should have lubed the cylinders prior to starting. When the camera was off, I also cranked the engine over for a a number of seconds without any plugs in it at a quicker pace to ensure it was cranking smoothly without any binding anywhere.

Magneto is freshly rebuilt, and has a VERY hot blue spark (thanks to Rudy Calin). Points on that are set correctly. Plug gap is set to .025". I am going to replace the spark plug wires (the ones I have are old, brittle, and likely to be original)... And triple-check my wire orientation. Wouldn't be the first time I have gotten the wires out of order!

I suspect the hunting issue is a problem with the idle circuit in the carb. Hopefully I can iron that out with a simple run through again.
 
T.R.K. and MMDEL,

Thanks for all the info. As I say, MM tractors are new to me - so it wouldn't be out of the realm of possibilities for me to have something
out of wack. I am going to start with new plug wires (these ones are original and very brittle), and then triple check the firing order I
have them set up in. Wouldn't be the first time I had something backwards.

I am guessing the hunting issue may be a idle circuit problem in the carburetor. Hopefully it is something that simple and less related to
governor issues. I definitely appreciate all the help, and will keep you all updated with (of course) more video, and that may be this
weekend or early next week. Work has me too busy for me to play around any more this week...

Stay tuned, and thank you!
 
Well,

Today I was able to get over and do a little work on the ZTU. Found out the issue regarding hunting was a stuck exhaust valve on #3 cylinder... Seems that we have it mostly freed up, but I think that there must be a little rust/carbon on the stem of the valve that is holding it open. Going to pull the head and take a look at the valves from the other side. Also noticed the oilers are not properly working so will have to give those some attention as well.

On a side note, I started my electrolysis process today on the fuel tank, but will have to probably do it a second time. Found a tiny puncture on the front wall of the tank that will need to be welded up and fixed. Not a big deal, been there done that.

Going to make some new spark plug wires, and go from there. Probably won't pull the head off until we get into our new house at the end of the month. Want to keep it running at least OK to get it on and off a trailer until then. Working on another video for that process.
a260907.jpg

a260908.jpg
 
Just checked out some of your Video’s Ken. Great stuff!
For carbon and sticky valves when you have the head off the best cleaner I have found is marine engine tuner. Johnson/Evinrude calls it engine tuner and Mercury Marine calls it powertune. It foams up and cuts thru all of the baked on gunk. Also makes a great carb soak for cleaning. Comes in spray can or gallons.
 
Good information, here... And THANKS! I am glad you enjoy it. I am definitely no professional, but learn as I go. Everything I know I have
picked up from people on this forum, members of some Facebook sites, and a few local guys here and there.

As a young kid I always wanted to see tractors on TV, and I guess this is my way of putting it out there for others to enjoy. I love getting
into a new project, and learning about a new brand. My soon to be wife, though... She is beginning to think I have 'enough'... I think we are
on a different page! :-D
 
(quoted from post at 20:08:02 03/11/18) Good information, here... And THANKS! I am glad you enjoy it. I am definitely no professional, but learn as I go. Everything I know I have
picked up from people on this forum, members of some Facebook sites, and a few local guys here and there.

As a young kid I always wanted to see tractors on TV, and I guess this is my way of putting it out there for others to enjoy. I love getting
into a new project, and learning about a new brand. My soon to be wife, though... She is beginning to think I have 'enough'... I think we are
on a different page! :-D

Right on my wife and I are 39 years old and have been married for 17 years. Her parents and mine are farmers so she gets it. But it can be hard to justify to here why I “need” another play toy.
 
I gotchya there. I am coming up on 32, she is 30. We don't farm, but you would think with 6 tractors we probably should! Oh well, we move to
our new home the end of the month with a couple acres... So that will help justify it a little. :)
 
I'm currently working on a video explaining the electrolysis process. Essentially, you mix 1/3 to 1/2 cup of washing soda (NOT baking soda)
to 5 gallons of water. Fill the tank with the solution, and then you have to run current through the water. Easy way to do this is to take
your negative cable from the battery source (either 12 volt battery or battery charger), and clamp it to the tank itself. Then, take your
positive lead and connect it to the electrode that is insulated from the tank itself, and inserted through the filler neck into the water
inside the tank. The Washing Soda then draws the rust off the tank, and to the electrode. I have had mine soaking about 7-8 hours now...
About to go drain it to take a look.

The pin hole I am going to weld up tomorrow, and then I will run another round of electrolysis tomorrow afternoon to ensure the entire tank
is rust-free.

My biggest issue is how to get the loose rust flakes out of the tank. Some I can hear are trapped on the far-side of the baffle inside the
tank. I guess I will just keep flushing it out the best I can. I also picked up a screen to solder onto the top of the sediment bowl to try
to prevent particles from getting inside the lines.
 
(quoted from post at 20:44:01 03/11/18) I'm currently working on a video explaining the electrolysis process. Essentially, you mix 1/3 to 1/2 cup of washing soda (NOT baking soda)
to 5 gallons of water. Fill the tank with the solution, and then you have to run current through the water. Easy way to do this is to take
your negative cable from the battery source (either 12 volt battery or battery charger), and clamp it to the tank itself. Then, take your
positive lead and connect it to the electrode that is insulated from the tank itself, and inserted through the filler neck into the water
inside the tank. The Washing Soda then draws the rust off the tank, and to the electrode. I have had mine soaking about 7-8 hours now...
About to go drain it to take a look.

The pin hole I am going to weld up tomorrow, and then I will run another round of electrolysis tomorrow afternoon to ensure the entire tank
is rust-free.


My biggest issue is how to get the loose rust flakes out of the tank. Some I can hear are trapped on the far-side of the baffle inside the
tank. I guess I will just keep flushing it out the best I can. I also picked up a screen to solder onto the top of the sediment bowl to try
to prevent particles from getting inside the lines.


Interested to see the end result. On my 37 ZTU I flushed a few times and coated with red kote. So far rust free. Also put a screen in the sediment bowl pickup threaded in the tank just in cases.
 
Well, after draining and flushing again... I will have to do some tank repair. Stopped counting at about 18 pinholes in the tank. Uff da. Not
sure if I want to weld them all or just go simple and easy and start spreading JB Weld all over everything.
 
(quoted from post at 22:43:41 03/11/18) Well, after draining and flushing again... I will have to do some tank repair. Stopped counting at about 18 pinholes in the tank. Uff da. Not
sure if I want to weld them all or just go simple and easy and start spreading JB Weld all over everything.
was in the same boat a few years ago. Ground paint off the outside so job weld would hold and redkote on the inside. Sealed up good.
 
(quoted from post at 20:42:19 03/11/18) You are very welcome, sir! I am about 30 minutes NW of Minneapolis, MN.
I am running out of Norwich Ontario. Had a Moline dealer here in Burgessville for years. Bros has an RTS he uses in the bush steady.
Red
 
You through me off course when you said the tractor was hunting. If you have a valve sticking open it would be a definite timed miss.

MMDEL
 
Right now it seems I have three issues:

#3 exhaust valve is sticking open....
Valve oiler is plugged in about 4-5 of the 8 locations
fuel tank is littered with pinholes on the front half...

Slowly but surely we will get there!
 
With the motor running, just take a pair of pliers, grab hold of those nails and rotate them back and forth till the oil starts to drip. You don't want the oil to run. You may have to move the nail up and down. After you get oil drip, you may have to bend the nail to aim it on the end of the valve stem.
MMDEL
 
I forgot to mention, you may be able to go though the spark plug hole with a thin punch and tap the valve back. Squirt some juice on it from both sides for a day or two first. If the valve isn't in the all the way open position. Drive it open just a tad with a hammer and a drift to break it lose. Then juice again let it sit and try to move some more. When going through the spark plug hole you will be at an angle, try to get as close to the center as much as possible so as not to bend the valve. Also sometimes you can grip the end of the stem with a vise grip and rotate the valve to loosen. When doing this mark the position of the valve on the retainer so when finished you can leave valve in the exact place where it was running because the mating valve and seat is where it will seal the best. You will have to remove that set of rockers to do this.
MMDEL
 
Thanks for the info! I will definitely try this next time I get over to work on it. Right now the project is to get the tank sealed up.
 

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