# Tiller dies under load



## Bseaton

I have a Troy built rear tine tiller model 21c-65m1011. I think I purchased in 2008-2009. Used very little. Ran rough last year but was able to till whole garden. Left in elements since last year. Would not start this year. Carb was full of crud. Gas tank was trashed - rust, crud, etc. I replace gas tank, cleaned carb, cleaned fuel line and new fuel nipple / screen. Also, new spark plug. Starts first time every time and idles forever - although slight rough.

When I put in gear tines and tires rotate fine - no change in engine speed or performance. The instant I lower the tines in the soil the engine dies. I can see governor arm push throttle open as it immediately dies. I then bought carb rebuild kit and did. Same results. Then I bought whole new carb and new air filter. Same results. Appear there is no fuel diaphragm or fuel pump. Seems like gravity fed. Pulled valve cover and blew out breather tube, it was clean. There is a slight pinch in the breather tube from going around housing. So, everything upstream from the carb (including carb) is new except the fuel line but I can see through it and seems perfectly clean - no dry rot etc. spark plug was gapped according to manual.

Not sure what else to try. I did read some posts on gap on valves, I have not done anything there. A coworker suggested checking springs. 2 new springs - throttle and governor springs are in transit. The governor spring is completely rusted. The throttle perfectly clean. Thanks in advance for your help!


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## paulr44

Try this test: close the choke partially by increments (at full throttle, and put tines down into dirt). 1/4 at first, then 1/2 (if has those settings), else go right to 1/2 as most have that detent. If it performs better or as it should, you'd know more right away.

By the way, fuel lines should always be replaced (and filters) when replacing or rebuilding carbs. due to gum/crud. Water or dirt contamination can be flushed from lines, gum and crud usually leave crap behind you don't want re-contaminating your system.

FYI If the governor is responding by opening the throttle and it dies, that tells you a lot. A weak governor spring will either not bring it up to full RPM, or, it would allow excessive droop.

I deleted a diatribe, with the intent you check as above and get back to us.


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## Bseaton

Ok. I tried the Choke test and it dies immediately no matter where the choke is set. I also replaced both springs and no change. Acts exactly same way. Any additional thoughts? Thank you for your help.


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## paulr44

I looked at the IPL for your unit, and the engine. If 2008, the engine is an MTD model 170-T0.

What I'm thinking, in looking at the engine design, is that when you're tipping it down into the soil, the engine is being tilted and the oil switch is shutting it down.

Mind you, if the oil level is low first fill it up and then try it in the soil before the doing the following tests.

Try either putting an inline spark tester on it to see if you lose spark, or, disconnect the low oil switch on the front of the block.

A governor arm will always swing toward WOT as an engine shuts down from full throttle. That's just physics in action, the centrifugal weights lose their force against spring tension.


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## Bseaton

First let me say thanks for your help this far Paul! Here is what I have done today. I can't find the low oil switch, I will keep searching. 

I checked the oil level it was dead on the high mark. I then made sure the engine was level by putting a level on it... It was slightly tilted. Once it was level I checked the oil and it was just slightly below the high mark. I then tried to emulate the tilted engine not under a load. I started he engine then 2 of us lifted the front end of the tiller to approximately a 45 degree angel. It idled fine.

Then a third person lifted the backend tines off the ground and engaged the tines - all (wheels and tines) rotated fine and engine did not die. We could lift the front end very high, all ranges from level to very high and no issues. Still seems to be an under load issue? Just for fun added a smidge more oil to bring it to high mark (wonder if I have too much) and tried again in soil. Same results - it died immediately. I put an in line spark tester in place and tested - idle is great spark, then engage and exact same results - it dies immediately... The spark seems strong even as engine is in process of dying... What is weird is I can't tell if the intermittent (while dying) spark is the cause or the result of the engine shutting down - happens fast.

I noticed that the breather tube from the OHV cover to the carb housing is slightly compressed where it goes around a piece of plastic on the housing - not sure if that creating any lack of vacuum issue. One other observation is that when the tiller dies with the tines in the soil I can crank it again in the exact same position where it was when it died and it cranks and runs fine in that position. Also found engine model on block 170-T0A. 

Thank you again!!


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## 30yearTech

Based on your description I would suspect the issue is still carburetor related. I would double check the main jet and nozzle assembly. Sounds like fuel is feeding through the idle circuit, but restricted through the high speed circuit, which becomes active the moment you add a load to the engine by loading the tines in the ground.


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## Lea Kuykendall

Wow! Thanks for all the info! I have a Powermate tiller that i am having same issues with and I just fixed the issue with the suggestions about leveling and the engine going back at an angle under load. Thank you!


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## MartyMarty

Bseaton said:


> First let me say thanks for your help this far Paul! Here is what I have done today. I can't find the low oil switch, I will keep searching. I checked the oil level it was dead on the high mark. I then made sure the engine was level by putting a level on it .... It was slightly tilted .... Once it was level I checked the oil and it was just slightly below the high mark. I then tried to emulate the tilted engine not under a load. I started he engine then 2 of us lifted the front end of the tiller to approximately a 45 degree angel ... It idled fine ... Then a third person lifted the backend tines off the ground and engaged the tines - all (wheels and tines) rotated fine and engine did not die. We could lift the front end very high, all ranges from level to very high and no issues. Still seems to be an under load issue? Just for fun added a smig more oil to bring it to high mark (wonder if I have too much) and tried again in soil. Same results - it died immediately... I put an in line spark tester in place and tested - idle is great spark, then engage and exact same results - it dies immediately... The spark seems strong even as engine is in process of dieing ... What is weird is I can't tell if the intermittent (while dieing) spark is the cause or the result of the engine shutting down - happens fast ... I noticed that the breather tube from the OHV cover to the carb housing is slightly compressed where it goes around a piece of plastic on the housing - not sure if that creating any lack of vacuum issue .... One other observation is that when the tiller dies with the tines in the soil I can crank it again in the exact same position where it was when it died and it cranks and runs fine in that position ... Also found engine model on block 170-T0A. Thank you again!!


I have a Husqvarna CRT500, it is doing the exact same thing! I have not spent much time on it, other than confirm that the throttle/fuel system is working as expected. My next step is to look at the bearings. My thoughts are underload condition, that there is slop in the engine/transmission bearings which create additional an additional shaft load, and thus dogs-out the engine.


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## KemoWasabe

I have a 2008 Husky CRT650 Tiller and after changing the oil, I began having trouble (stalling when the tiller was not level). At 1st, I thought I must have over-filled the oil and drained some out but the problem persisted still. I have since rebuilt the carburetor and installed a new float, cleaned the tank and put int new lines thinking fuel might be contaminated and added some Sea Foam without any luck. However - I believe it has to do with an oil sensor. Where is this sensor located as I've heard it mentioned in other blogs and the owner's manual said that if oil is low, it will shut down? When it runs, it runs strong but let it tip to the left or right; it coughs and dies. Thanks - Kemo


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## paulr44

In the future, please start a new thread.
In order to answer your question, we'd at least need to know what brand engine is on it, preferably engine numbers as well.


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## Zap45

Sounds like I have the same tiller as Bseaton. His scenario is exactly as mine. Ran rough last 2 seasons ago with surging engine but still did the job. Did not use last season. This season it started up and tilled for two runs with choke full choke (I had added some Seafoam when it started and was running rough thinking that it might clear up) and it died. Cleaned the carb thoroughly, completely emptied and cleaned the tank, confirmed good gas flow to bowl, fresh gas, good spark plugs, and engine runs but only with full choke (I can tell that it's running should I say "weakly". Just like Bseaton stated, as soon as I put the tines to the soil it dies. This is not an engine stalling such as some kind of sensor. It's stalling because it's running "weakly" from the start. By the way I have repeated the carb cleaning 5 times thinking that I might have missed something. Bseaton has gone a step further by replacing the carb completely. I was getting to ready to order a carb replacement but stumbled upon this forum. I have had this exact same scenario before and a very cheap carb replacement solved that problem immediately to my surprise. I have yet to do a OHV adjustment. My mechanical experience brings me to the carb. I don't believe (or know) if a oil sensor would cause a engine to run rough, weak, or surging, or the need to have it fully choked to even run.


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## dfields5685

I'm having the exact same issue with my craftsman rear time tiller. I think it is from the late 70's-early 80's. It is CRT 500 I think. At any rate, it has a 3.5 HP B&S engine and is a 14" cut. Starts fine, idles fine, runs full throttle fine, but as soon as you start tilling, it begins to bog down and will eventually will die. Any ideas?


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## paulr44

If it's that old, it may have a high-speed mixture screw. Look on the side of the carb. for a screw with a spring. If it sits about 1/4" above the tank, turn it CC in 1/8 turn increments and test under load.
If the screw is almost flush with the tank it's probably a low speed mixture screw and won't help the problem.


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