Kohler Mag 18 - 1872 Tractor

[mpatterson]

Having issues with both my Mag 18 & 20 dumping fuel into engine. Have since put Mag 20 on back burner since the governor gear went on it, so a tear down is in order for it! Good Grief!

So I ended up replacing the fuel pump on the Mag 18 with the regular mechanical one - brand new from Cub Cadet dealer. I ran it for maybe 4 hours total while blowing snow with it last year and I checked the oil the next day because I could smell gas in the garage - dip stick was nice and shiny and smelled of gas. Not a drop of oil on it since there was so much gas dumped into engine. Drained it and had twice as much fluid come out than should have. SO... what is my issue? Is it the carb that is the cause of my frustrations that its allowing the gas to dump back into the engine? I notice today that when I removed the carb with idea of stripping it down and doing a rebuild, there was engine oil in the base of the air filter housing. Guessing its been spit up into it? I started to look a little more at stuff and the small plates over the vales revealed some dirty crap - at least I think its dirty - guessing its not normal? My biggest concern is there a gasket or seal gone in the engine that I don't know about that is needing replacing? I'm no engine mechanic, so apologize for stupid questions. Will complete rebuild of the carb possibly solve my problems?
I recently bought an ultrasonic machine for cleaning small stuff. It worked wonders on my carb off my ATV this fall. Knock on wood the Simple Green solution solved my issues I had with it and its a daily runner again. So figured it would likely do some good to put the carb off the Mag 18 into the solution for a cycle or two?!
Attached a couple pictures of what the valves look like. Not really sure what the white crusty build up is or the reason the one side is "burnt" in the corner? I am not the original owner of this tractor, it came from PA and not sure where from before that?
Any info/suggestions would be greatly appreciated.

 

[memorgan]

problem i have had before is a bad float or needle and seat
the float can look like its just fine, but over years of use, it can have such a small leak or crack that you never see it,
one way i have found to see if the float is taking on fuel is to remove it from the carb, dry it off quickly and set it on a dry surface or paper towel,
if its full, you should end up with a wet spot..
also, make sure your fuel bowel is clean

 

[mgonitzke]

If that has a Walbro carb, get a KT-17 series I adjustable carb, or a K-series #26 carb, switch the throttle and choke shafts from the Walbro into it as necessary, and toss the rest of the Walbro. Carb kit for that is expensive, and as I recall, the seat is not replaceable, only the needle. Either that, the float has a hole in it (today's gas eats the plastic floats eventually) or the float level is set wrong, in order of decreasing likelihood.

White crusty stuff is not in focus in that picture so it's hard to tell what it is. I haven't observed anything like that before. Maybe it's just the picture, but there doesn't appear to be much oil getting to the valves on that side. The other side, the black buildup is from oil coking onto the exhaust valve stem. That's a worn exhaust valve/guide (and seal if equipped). Some oil in the air intake from the breather is normal. Excessive amount is not normal. I wouldn't get too excited about it unless the oil consumption is excessive.

 

[mpatterson]

Ok added a couple other pictures to see what white stuff is. So why is that side not getting enough oil to lubricate it? Something that is repairable? What about the worn valve/guide - that something that should be addressed before installing motor again or likely ok for a while longer depending on how many hours I put on it?
I might have a carb off a KT series 1 still - WOW! If I do I should go buy a lottery ticket, saving something and actually needing it in the future!
I have not used the tractor enough to know how much oil it uses. If I'm lucky I've put about 10 hours maybe 15 if lucky since I bought it a couple years ago. Haven't had it running problem free long enough to know.

 

[mpatterson]

If that has a Walbro carb, get a KT-17 series I adjustable carb, or a K-series #26 carb, switch the throttle and choke shafts from the Walbro into it as necessary, and toss the rest of the Walbro. Carb kit for that is expensive, and as I recall, the seat is not replaceable, only the needle. Either that, the float has a hole in it (today's gas eats the plastic floats eventually) or the float level is set wrong, in order of decreasing likelihood.

White crusty stuff is not in focus in that picture so it's hard to tell what it is. I haven't observed anything like that before. Maybe it's just the picture, but there doesn't appear to be much oil getting to the valves on that side. The other side, the black buildup is from oil coking onto the exhaust valve stem. That's a worn exhaust valve/guide (and seal if equipped). Some oil in the air intake from the breather is normal. Excessive amount is not normal. I wouldn't get too excited about it unless the oil consumption is excessive.

Pictures of the carb that is currently on it. I have to dig the KT17 out of a snow bank to get under the tarp to see what's left of it. Was of course the one that was left outside under a tarp when filling up the shed with parts tractors, thanks to the local wasps moving in! Little SOB's!
This is the valve on the side that has the white crap "growing" in the corner.
Also in one of the pictures above, you can see the crap stuck in the hole between the two valves, that is what I'm guessing is the oil lube hole and that's why Matt said it looks like its been starving for oil????

 

[mpatterson]

So I picked up a rebuild kit for the Walboro carb just in case the other day - can return it if needed. Also brought home a complete carb assembly, off shore replacement that Cub dealer stocks now. Supposed to be an exact match to the Walboro's but its adjustable. Upon closer inspection as Matt had mentioned above, the carb I had on wasn't adjustable (like I thought, or at least not fully adjustable).

Soooooo.... I installed it this morning. Had to switch out the choke lever though with the old one. That way the end where the choke cable attaches would be facing up instead of down. Figured this would make the install a bit easier! We'll see if this will work in the end or not - hopefully it will.

Sucked all the white crap out of valve chambers and made sure they were nice and clean. Since it is minus stupid here in Ontario - I can't pressure wash the frame down to get rid of all the oil and grease built up, or clean the outside of engine off properly. I picked up some brake clean to spray it down and wash up as best as I could. Small brush and rags are going to have to be my friend for a bit along with a putty knife. Hopefully I can finish cleaning it up good enough so I can put the Mag back in this week. Supposed to warm up again for a couple days, so that will be nice!

 

[mpatterson]

So I finished installing the new carb assembly yesterday on the Mag 18 and got engine back into tractor after doing a clean up of the frame and just about every part in front of the steering column. What a mess! PO obviously had a hose blow or something, everything was caked on with oil and dirt. You can actually see through the screen on the bottom of frame now!
Fired it up yesterday with shock in my face I'd have to admit. It cranked over about 4 times and it ran. It ran good too! I adjusted the carb according to manual for the Walboro adjustments - hoping it was close. I ran it for just about an hour and it seemed to work good. I can rev it up and idle it down with no problems. Figured I'd test it out and leave the fuel turn ON for the night to see if it would flood everything.
Went out this morning.... NOPE! All was good. Choked it and it cranked a couple times and fired right up! Went for a tour around the yard a few times and all works well. I think the bearing is starting to go on the clutch as its a bit loud when its NOT engaged. So will have to look into that one before installing the grill again. So far I am impressed with the aftermarket carb assembly. Nice to see for once. Now I can return the carb kit and float I bought to fix the old carb.
If this keeps working well, I'll have to actually finish my other cab door and install it. Be nice to get the tractor all back to looking normal and not half torn apart in the garage.

 

[rfunk]

I feel for you with the temperatures! Manitoba has been a bit chilly this winter too - and I've had to pull apart the K321 on my 149. Three quarters of a quart (or more) per tank of fuel is a bit crazy. My shop is poorly insulated, and only heat is a 4800W construction heater. Takes 2-3 hours to get to+3C//37F.

 

[rchamberlain]

So I finished installing the new carb assembly yesterday on the Mag 18 and got engine back into tractor after doing a clean up of the frame and just about every part in front of the steering column. What a mess! PO obviously had a hose blow or something, everything was caked on with oil and dirt. You can actually see through the screen on the bottom of frame now!
Fired it up yesterday with shock in my face I'd have to admit. It cranked over about 4 times and it ran. It ran good too! I adjusted the carb according to manual for the Walboro adjustments - hoping it was close. I ran it for just about an hour and it seemed to work good. I can rev it up and idle it down with no problems. Figured I'd test it out and leave the fuel turn ON for the night to see if it would flood everything.
Went out this morning.... NOPE! All was good. Choked it and it cranked a couple times and fired right up! Went for a tour around the yard a few times and all works well. I think the bearing is starting to go on the clutch as its a bit loud when its NOT engaged. So will have to look into that one before installing the grill again. So far I am impressed with the aftermarket carb assembly. Nice to see for once. Now I can return the carb kit and float I bought to fix the old carb.
If this keeps working well, I'll have to actually finish my other cab door and install it. Be nice to get the tractor all back to looking normal and not half torn apart in the garage.

Mike, your problem sounds like a similar thing I have going on with my 1811. I have more investigation to do, because I pushed it aside and got another mower, but fuel dumping had me scratching my head. I am not a mechanic but can figure things out with a little help. I am outside Kingston, any chance you are near? Where did you get the necessary parts to do your repair? Thanks for any help, Rob.

 

[mpatterson]

I feel for you with the temperatures! Manitoba has been a bit chilly this winter too - and I've had to pull apart the K321 on my 149. Three quarters of a quart (or more) per tank of fuel is a bit crazy. My shop is poorly insulated, and only heat is a 4800W construction heater. Takes 2-3 hours to get to+3C//37F.

Yeah the older I get the more I hate winter. I was running a propane heater in garage, but after 4 or 5 hours ya start to get a bit spacey! And that's with a few "air gaps" around doors. Just bought a 5000W heater a few weeks ago. It's nice, hard wired in 220V. I am thinking the propane would be needed to start to warm up on really cold days still?

We are in warm spell now, snow melting off roof and well making a total mess as usual. My garage sits lower than driveway by about an inch. Every spring or thaw in winter - I get a lake inside. PIA! So by end of week I will be able to skate in garage when it freezes again. Always have to keep floor picked up in case of flood. Don't need to chip a wrench out next day!

I do not know how you put up with winter in Manitoba! You guys always get hammered out there!

Sucks about your 149, did you find the source of problem yet?

 

[mpatterson]

Mike, your problem sounds like a similar thing I have going on with my 1811. I have more investigation to do, because I pushed it aside and got another mower, but fuel dumping had me scratching my head. I am not a mechanic but can figure things out with a little help. I am outside Kingston, any chance you are near? Where did you get the necessary parts to do your repair? Thanks for any help, Rob.

Hey Rob
You aren't too far from me, 1.5 hours or so. G.C. Hudson in Brockville is where I get my parts. Used to be IH dealership years ago, now just a Cub dealer. They are a big rental company for contractors too. Owner, Steve has an amazing collection of old stuff. His museum he has there will make your head spin if you are ever fortunate enough to visit it.

Every Cub I own has done the same thing now. I have come to conclusion that the carbs and or fuel pumps are finally showing age and need replacing or rebuild. A year or so ago, I started putting a bit of Sea Foam in my gas.....I think I cleaned off all the built up varnish in the engines and that's where my problems started. Seems like ever since I used that stuff, problems have become the norm. So the question of does sea foam work? Yep! It cleans a lot of stuff up in my opinion. Just need to be prepared to finish the job afterwards and clean everything else or know your worn out parts will show their ugly face!

Matt mentioned above about the junk Walboro carb - an really starting to agree with him. They may have worked ok when new, but as they get older I think they start to show their true, poorly designed features???

The after market carb I bought seems to be good so far - only kicker was I needed to use parts off my old carb to make it work on the Mag 18. The choke and throttle shafts were not right on new carb, so had to switch them out. Works ok as long as your old carb is the same.

I was going to switch to electronic fuel pump that Kirk's sells, but held off in Hope's the carb was source of problem and could still use mechanical pump. So far all is good on it!

 

[jbland]

all the cub's that I have owed, I have install very inexpensive electric fuel pumps on them and bypass the mechanical one

 

[rchamberlain]

Thanks Mike. I forgot about Hudson's. Had deck belts delivered from them when I got this Cub. Will have to go there when it warms up and dries up since I have to do any work outside.

 

[rfunk]

. . .
Sucks about your 149, did you find the source of problem yet?

Got the K321A apart. Glazed cylinder where the rings travel, PTO side seal so hard it crumbled. (painted, so probably original) Edge of piston chewed up adjacent to valve side of cylinder. Intake valve very wobbly in guide. Better news, NO scoring on cylinder, connecting rod journal, no lip worn into cylinder. Piston marked "STD", so hasn't been rebuilt before. Going to get it measured to see what I need, then Charlie's getting an order . . .