Oil & Fuel MF 230 Carburetor Questions

   / MF 230 Carburetor Questions #1  

Sbalak

Member
Joined
Oct 31, 2012
Messages
43
Location
Lunenburg, MA
Tractor
2018 Kioti DK4710SE Cab
I'm pretty sure my tractor is running rich, because I recently replaced some fouled plugs and I also have trouble keeping her running without some choke. I was going to pull the carb and try to clean it out, but I thought I'd start with trying to adjust the mixture. I've looked at it and the partsbook and I can't find a mixture screw. I clearly see the idle set, but the tractor idles nicely at 750rpm with a little choke. Am I missing something? Thanks for your help. Scott
 
   / MF 230 Carburetor Questions #2  
I'm pretty sure my tractor is running rich, because I recently replaced some fouled plugs and I also have trouble keeping her running without some choke. I was going to pull the carb and try to clean it out, but I thought I'd start with trying to adjust the mixture. I've looked at it and the partsbook and I can't find a mixture screw. I clearly see the idle set, but the tractor idles nicely at 750rpm with a little choke. Am I missing something? Thanks for your help. Scott

What does the fouling on the plugs look like? If it wet and oly looking, that's not cuase by an eriched mixture. it's caused by loss o f oil control. Dry, sooty, fluffy deposits are caused by enriched mixtures. Requiring the choke to run generally means too lean a mixture or an air leak downstream of the carbs metering system.

What does your spark look like? It should be FAT AND BLUISH WHITE, the color of lightning. Do you have the right heat range on the plugs, the correct gap, and do you have the correct firing order and intial timing?
 
   / MF 230 Carburetor Questions
  • Thread Starter
#3  
I've got new plugs (AL386) in now with the correct 0.25 gap. Hmmmmm, not good....The old plugs (all 4) were oily & wet, not dry & fluffy. I guess that means I've got an oil leak. I ran the tractor for ~20 minutes this past weekend so the new plugs do have some time on them. I can pull them and see if they also now have oil on them as well. I'm pretty sure the fire order is correct, because she starts right away and runs pretty smooth (with choke). I'll take another look at distributor cap tonight, but I don't think it has a timing adjust (rotate) as it feels pretty fixed. After my post, I did notice that #4 cylinder spark plug wire could be replaced. That'll be next on the list.

When you say downstream, are you thinking head gasket or valve? The oil pressure gauge shows good pressure while running. I purchased the tractor in the summer and I would say that my need for choke is directly correlating with cold temps. I'm wondering if I've got seals that are shrinking in the cold.
 
   / MF 230 Carburetor Questions
  • Thread Starter
#4  
Now I feel like a complete moron...the correct firing order is 1,3,4,2 and mine is setup for 1,2,4,3. I'm amazed it even starts. :) It's tucked in the garage pretty tight so I'll pull it out this weekend, try it out, and I'll post an update. Thanks for the advice! Scott
 
   / MF 230 Carburetor Questions #5  
I've got new plugs (AL386) in now with the correct 0.25 gap. Hmmmmm, not good....The old plugs (all 4) were oily & wet, not dry & fluffy. I guess that means I've got an oil leak. I ran the tractor for ~20 minutes this past weekend so the new plugs do have some time on them. I can pull them and see if they also now have oil on them as well. I'm pretty sure the fire order is correct, because she starts right away and runs pretty smooth (with choke). I'll take another look at distributor cap tonight, but I don't think it has a timing adjust (rotate) as it feels pretty fixed. After my post, I did notice that #4 cylinder spark plug wire could be replaced. That'll be next on the list.

When you say downstream, are you thinking head gasket or valve? The oil pressure gauge shows good pressure while running. I purchased the tractor in the summer and I would say that my need for choke is directly correlating with cold temps. I'm wondering if I've got seals that are shrinking in the cold.

I hope you mean 0.025" spark plug gap!

Downstream means from the throttle plate to the cylinder head. Air leaks can occur at the throttle shaft , the carb to manifold interface, cracks or rust spots in the manifold or at the manifold to cylinder head gasket. To retime the distributor, you best have a timing light. Then you have to loosen the distributor with the engine running and you check the timing with the timing light and adjust by rotating the distributor appropriately. You should also check the advance mechanism for functioning.
 
   / MF 230 Carburetor Questions
  • Thread Starter
#6  
I tried the 1,3,4,2 and she wouldn't start at all. Looking at it 1,3,4,2 is that same as 1,2,4,3 if you go counter-clockwise! :) So I set it back and she's running just like before. Yep, the gap is 0.025 not .25. I finally got my hands on a used timing light (harder to find these days) and I was able to set my timing. I've got her set at 6 degrees on idle and I get to the high twenties on full throttle. I think you're supposed to get to 36, but I was pretty happy with the advance. I took a couple pics just in case somebody else needed to do this on their continental. I'm still needing the choke, so now that I've eliminated timing I'll start looking into cleaning the carb.

There's plug just under the starter right where the engine meets the transmission. Pop off the cover and you can see the degree scale. Mine had a nice white mark at 6 degrees.

Inductive pickup on #1
2013-02-10_16-25-41_554.jpg

Looking down the tractor towards the timing hole
2013-02-10_16-26-08_137.jpg

Timing light close to read the scale
2013-02-10_16-28-59_387.jpg
 
   / MF 230 Carburetor Questions #7  
I believe you'll find the distributor turns CCW and if the firing order is 1-3-4-2( generally the numbers are cast into the block), make sure you have that correct. it looks to me like you have 1-4-3-2 currently. You said you set the timing at 6 degrees. Was that BTDC or ATDC? It should be BTDC.

What's the thing that looks like it's attached to the distributor in the first photo? It looks like a connection for a vacuum advance. If it is you need to either connect that to it's vacuum source or plug the engine end of that or it will lean out your mixture.
 
   / MF 230 Carburetor Questions
  • Thread Starter
#8  
It's 6 BTDC. The add-on piece to the distributor is the mechanical tachometer drive. The gear in that unit failed, so I've replaced the mechanical tach with an electronic version that triggers off the coil pulse. I looked for a vacuum hose for the timing advance and couldn't find one so I'm guessing it's a mechanical advance. I don't exactly know how it works, but I know that it's working based on the timing advance I see on full throttle.
 
   / MF 230 Carburetor Questions #9  
I tried the 1,3,4,2 and she wouldn't start at all. Looking at it 1,3,4,2 is that same as 1,2,4,3 if you go counter-clockwise!

The correct firing order for the Continental Z-145 engine is 1-3-4-2 and the distributor rotates counter clockwise. It's important to note that the number one cylinder is at the front of the engine, where the cylinders front to back (not firing order) are 1-2-3-4.

I looked for a vacuum hose for the timing advance and couldn't find one so I'm guessing it's a mechanical advance. I don't exactly know how it works, but I know that it's working based on the timing advance I see on full throttle.

The distributor does use a mechanical advance mechanism, where fly-out weights are attached to small springs known as curve or advance springs. The weights and springs are located beneath the bottom plate that the points and condenser attach to. Problems with the springs can result in timing advance issues, especially if the springs are weak or broken. If new timing advance springs are needed, they can often be purchased at auto parts stores as part of what is called a distributor curve kit which comes with many different springs for different performance characteristics.

The following diagram shows the shaft and internal components of the distributor used on the earlier versions of the Continental Z-145 engine, such as the one on the Massey 135 tractor I'm currently restoring. It's a little different than the distributor on yours, but it should give you a general idea of how it all works. The fly-out weights are part number 19 and the advance springs are part number 20.

xlaxb7.jpg
 
   / MF 230 Carburetor Questions #10  
It's 6 BTDC. The add-on piece to the distributor is the mechanical tachometer drive. The gear in that unit failed, so I've replaced the mechanical tach with an electronic version that triggers off the coil pulse. I looked for a vacuum hose for the timing advance and couldn't find one so I'm guessing it's a mechanical advance. I don't exactly know how it works, but I know that it's working based on the timing advance I see on full throttle.

What about the firing order? The picture looks like you may have it incorrect.
 
 
Top