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ulav8r
12-11-2010, 06:43 PM
Need to get help with adjustments to a carb on a MF135. It is a '73 or '74 gas with a Zenith #013338 carb. Was bush hogging earlier this fall and could just keep pto at 540-560 rpms, engine maxed out at 2000 rpms. Things got worse and inspection found the sediment bowl screen covered in rust and the bowl about 1/2 full of sediment. The filter at the carb was also full of rust. Managed to break of the brass elbow the filter was screwed into, so had to remove the carb to get the broken part out. Got a carb rebuild kit to get replacement gaskets. Cleaned the carb thouroughly, and replaced the float shaft and the brass seat and needle that is operated by the float. Left the other jets and components alone. Just got it back on and started. The engine revs to over 2500 rpms and the throttle will not slow it down. I re-checked the linkage and it is hooked up properly. The throttle butterfly was not removed while torn down, so it should be OK. The choke linkage also works as it should. I tried closing down the screw(needle valve) just below the throttle shaft and that had no effect.

I have a little experience working with engines, but need guidance.

This is my Dad's tractor but he is in a rest home with Alzhiemers and was not any better at mechanic-ing than me. I have the operator's manual but it is no help.

Thanks in advance for any help you can give.

Gravy
12-11-2010, 06:52 PM
90% odds the throttle butterfly is stuck partly open. Disconnect the linkage and see if the butterfly shaft lever moves freely and closes firmly against the idle stop. You may have to remove the carb to look at the butterfly. It should close to within maybe 1/16" at the widest part of the gap.

JanvanSaane
12-11-2010, 07:20 PM
I am not sure on your MF but could the spring that pulls the lever back on the govenor have slipped off? Vaguely remember my 8N having a spring that pulled the lever back on the govenor that ran the throttle. Jan

ulav8r
12-11-2010, 07:36 PM
I'll check it tomorrow.

jdunmyer
12-11-2010, 08:34 PM
If you're going to continue working on that tractor, get an I&T shop manual for it. While not as comprehensive as an official factory service manual, they're usually good enough and inexpensive to boot. Places like Tractor Supply carry them (or used to!), or you can order here: http://www.tractorpartsinc.com/service_manual_itmf27_2937_prd1.htm Price is only $33.00.

The governor linkage has a spring that pulls the throttle open; the governor closes the throttle. Operate the throttle (speed control) lever from idle to WOT and observe the throttle on the carburator. It should be closed at "Idle", and go wide-open long before the speed lever is full-on. Do this with the engine Off!

Make sure you have your hand on the ignition switch when you try it, don't let the engine over-rev.

v860rich
12-11-2010, 09:47 PM
Look for a vacuum leak!!!

THANX RICH

People say I'm getting crankier as I get older. That's not it. I just find I enjoy annoying people a lot more now. Especially younger people!!!

kc5ezc
12-11-2010, 10:32 PM
ulav8r: I have the same tractor. 3 cylinder GAS Perkins with zenith carb. hav not checked the carb number. I have the full service manual from MF. If I can copy and send you a few pages by email let me know.

Peter S
12-11-2010, 10:33 PM
I too would be checking the linkages from the governor, and the way they connect to the carb. Normally the hand throttle does not connect to the carb at all. The hand throttle simply changes the governor's spring pressure.

So I would be looking to see what happens when you open the throttle lever wide (engine off), it should increase the force from the governor holding the throttle open. Is it possible to get the linkage, or the arm on the throttle shaft, mixed up (upside down?) so it it doing the opposite of this?

If the short arm on the butterfly shaft had been removed, I would check that first probably.

Note: I have not seen one of these tractors, just taking a guess based on other engines.

J. Randall
12-11-2010, 11:23 PM
I think the others are on the right track, sounds like you have something fouled up on the governor spring or linkage.
James

ulav8r
12-12-2010, 01:29 AM
Thanks all. Email sent to kc5ezc.

ulav8r
12-12-2010, 11:26 PM
Checked the governor linkage, seemed to be OK. By leaving the choke on, I ran it long enough to to get the bush hog hooked up and in the barn. I will get back to it later. I am three hours away so can't work on it every day.

Will probably tear the carb down again, should I use some kind of sealant on the gaskets?

Looked at changing the spark plugs and could only see one of them. Looks like the exhaust manifold or the gas tank will have to be removed to get to the rear three plugs. Will also have to find a 7/8 plug socket.

jdunmyer
12-13-2010, 09:43 AM
Disconnect the fuel line at the carb, then turn on the gas valve. Have a coffee can or something under the end of the line while you check to see that you have a good flow of fuel out of the line.

A.K. Boomer
12-13-2010, 10:02 AM
Mark the throttle at totally closed position and verify that its staying there whilst operating --- its real simple, you either have an improperly assembled governor and or linkage/springs OR you have a massive vacuum leak,

engines need two things to run past idle - more fuel AND air, so unless your using some kind of anaerobic fuel look for a place where its getting more air - I suspect your throttle plate is cracking open some as it would not take much at all -- I suspect this more than the other due to the plate compensating for fuel air mixture due to the airflow having to go past the carb venturi,
A vacuum leak elsewhere will most likely result in a mixture too lean to run @ that kind of RPM without falling on its face...

Need to add; You could reassemble the carb and governor linkage to the T - exactly the way you took it off and it could still be the problemo,,, carbs (esp. from that era) mounted on very loose fitting bolt holes that can totally change the governor's linkage function too them -- every time a carb is removed and put back on the governor should be re-calibrated...

J. Randall
12-13-2010, 10:04 AM
Carb gaskets don't need sealant if they are new from a kit, I have added a little between carb and manifold if reusing an old gasket. Since you rechecked and are sure that springs and linkages right, I would bet on a bad vacuum leak somwhere, either between the carb and manifold or elsewhere. Running with choke on is probably cutting down the extra intake air enough to limp it into the barn.
James

studentjim
12-13-2010, 10:49 AM
Sometimes the hole in the carb body where the shaft pivots gets worn oversize and this lets air enter the venturi and causes the engine to rev. I have had this to happen on older engines. This can be repaired by oversizing the shaft hole and installing a bushing. ....Jim

Black_Moons
12-13-2010, 02:35 PM
You mentioned your carb was FULL of junk, And you did not clean out the jets? That seems highly suspect to me. Cloged jet can cause all sorts of problems.. Such as being too lean and overreving/heating.

Spray the jet out with carb cleaner, Blow it out with shop air, and hit it ever so lightly with a gas torch 'cleaner' tip of the correct size. Do NOT enlarge the jet with the cleaner, Just clean it. (ie just a stroke or two)

Ever since I learned about engines, it seems most of my problems are a cloged jet every year or two.

shadtree
12-13-2010, 05:56 PM
Ck your float level and seat. If your float is stuck or needle is not seating you're flooding the engine with gas and causing the over-rev.

Peter S
12-13-2010, 06:14 PM
Will probably tear the carb down again, should I use some kind of sealant on the gaskets?

I would use a bit of grease on the old gaskets, not sealer.

Were all the jets removed and all passages blown out with air? If no compressed air available, I use a bit of say 1/4" plastic hose, apply to each hole, and blow through it.

A.K. Boomer
12-13-2010, 07:58 PM
Ck your float level and seat. If your float is stuck or needle is not seating you're flooding the engine with gas and causing the over-rev.



without air its exactly like you state "flooding the engine with gas" but this in no way causes an "over rev" --- it kills the engine and actually makes it hard to re-start...

Ohio Mike
12-13-2010, 08:24 PM
I just replaced a carb on an Allis WD-45. It was supposed to be set to factory but I had a similar issue in that it tried to run but just wouldn't. Adding choke helped which told me I wasn't getting fuel. I turned the idle way up which allowed it to start, once I got it started then I could back the idle down. That said my carb was a rebuilt by a professional so if you're not sure the carb is clean I'd start there.

ulav8r
12-13-2010, 09:25 PM
Thanks to all. I probably won't get back to it till after Christmas.

When I opened up the carb there was no signs of trash in it. There was soot on the removable venturi and part of the bore above it. The throttle seems to close completely and the governor linkage was only disconnected at the throttle shaft. The float was adjusted according to the dimension given on the rebuild kit documentation. I tried closing the throttle at the end of the shaft, it moved maybe a 1/16 of an inch and slowed down a little for a few seconds. With the choke on and the throttle lever at it's lowest limit, it ran at about 2100 rpms and was slightly rough.

kc5ezc
12-13-2010, 11:25 PM
ulav8r: I tried to send an email to the address shown in the msg sent to me, but it came back.
Sounds like you have a continental engine instead of a perkins. The perkins has only 3 cylinders. I have no info on the continental z-145 carb; unless it is the same as the perkins. Nothing in the service manual. I will send the throttle linkage and govenor setup if I can get a good email address.
you can call 580-332-1063 if you desire. I'm here unless I am gone!
I am usually around the place.
Sorry I couldn't be more help.

Jon Leary
12-14-2010, 12:02 AM
Sounds like you have the governor spring pulling the opposite direction that it should be.

Gently
12-15-2010, 06:47 PM
Thanks to all. I probably won't get back to it till after Christmas.

When I opened up the carb there was no signs of trash in it. There was soot on the removable venturi and part of the bore above it. The throttle seems to close completely and the governor linkage was only disconnected at the throttle shaft. The float was adjusted according to the dimension given on the rebuild kit documentation. I tried closing the throttle at the end of the shaft, it moved maybe a 1/16 of an inch and slowed down a little for a few seconds. With the choke on and the throttle lever at it's lowest limit, it ran at about 2100 rpms and was slightly rough.

Is it an original Carb to the tractor and not a Marvel replacement? If it is a zenith factory for the tractor then it is most likely your jets (a complete teardown and 3 or 4 day soak my help. It also should have a screen in the inlet on the Carb, check it to make sure it is not fouled up. On a cont. Z type engine check your INTAKE/EXHAUST bolts to make sure they are tourqued to specs, I have seen more than a few do what you describe because all or most of the manifold bolts are loose (lots of air little fuel=overrev) also check for cracks and holes in the manifold. FYI that type of tractor should only rev about 2400 no load more that that and the gov is set wrong and it will not have any "power" lots of revs but no power. I have a Z134 cont, but I have a Marvel schiber(?) carb. if you can post a picture it would help a lot.
My 2 cents worth!

ulav8r
12-15-2010, 10:08 PM
Original carb, ran fine last year for about 5 days worth of bush hogging. Ran for a day and half this year before the rust clogging the system was found. Loosened the clamps on the fuel filter and broke off the fitting the filter screwed into the carb. Then disconnected the throttle/governor linkage at the carb and the choke cable at the carb. Took off two nuts and dropped the carb off to get out the broken end of the fitting. Split the carb to be sure there were no parts of the fitting inside. Used carb cleaner to remove soot and flush out all passages. The governor spring and and connections were not touched. Then reassembled and installed, ran too fast.

When I get back to it, I will pull the carb again and re-check everything there. Then I will check the governor adjustment. The last time I tried it, I also noticed the the exhaust manifold gasket is leaking, so I will also replace that before it causes further damage.

Gently
12-15-2010, 11:34 PM
When you reassemble the gov. assembly make sure you take ALL of the slack out from the throttle arm, Best way to do this is lock the throttle lever all the way up, it should be almost verticle, then use non marring pliers (rubber coated, best way it to dip them in liquid electrical tape) and take ALL of the slack out of the Gov shaft and then tighten it down. Even a little bit of slack will cause the Gov to overrev.

If you have a Tractor supply store nearby you can get the gasket for the intake/exhaust manifold there, if the bolts are loose take the time to replace the STUDS and the bolts (I think they are 3/8x16 studs and 1/2x16 bolts, dont quote me its from memory) it will mkae you efforts well worthwhile!

It is either the gov adjustment or the Manifold...precluding theat the carb has been cleaned and put back togeather properly.

Hope this helps. I will se if I can find my manual for my massey 50 with the Z-134and carb settings for the Zenith. It will be after Christmas though, I will check back later, to see if you solved your problems.

J. Randall
12-16-2010, 09:48 PM
ulav8r, the more I think about your problem, I just have to ask one more question. Are the rod ends from the throttle and governor the same (the little spring loaded ends that snap onto a ball), if they are is there any possibility you switched positions?
James

ulav8r
12-16-2010, 11:03 PM
The throttle shaft has a plate on it. The rod from the govenor to the throttle shaft has a right angle bend that fits through a hole in the plate. A clip holds it in place. That one connection was the only part of the throttle linkage that was disconnected. There was no way to re-connect incorrectly without disconnecting more parts first.

Ohio Mike
12-17-2010, 04:38 PM
On the Allis there is governor spring in the governor body that can come loose if the throttle linkage it pushed beyond normal when unhooked. That will cause the throttle to run wide open when reconnected. Moving the throttle lever does nothing because it's no longer connected to the carb push rod.