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New Engine stops runing when I till for about 5 minutes

Posted by mrlarry1953 (My Page) on
Mon, May 24, 10 at 22:25

Help, I have a old Troybilt Horse tiller. It had a 6HP tecumseh engine on it, that needed a carburetor. I was reading some post in here and read where someone had put a 6.5 OVH greyhound, (from Harbor Freight)on one of their horse tiller and said he had no problems. So i decided to get one. I paid 103+tax brand new out of the box. I Thought that was a better deal then just a carburetor for the Tecumseh. The engine runs great. I let it run for about 5 or 6 hours before using it. and still am gentle with it till I reach the 20 hour break in period. Heres my dilmma. It stalls about 5 or 6 minutes after I start to till. I have disconnected the low oil wire, and the engine runs fine standing idle but stalls everytime I start to till. I think the float in the carburetor is causing the problem. Anybody have any idea whats the problem. Again the engine purrs like a kitten when idle..

Follow-Up Postings:

RE: New Engine stops runing when I till for about 5 minutes

I when to trouble shooting school once antilize your problem with second carburator on to different egines would be dirty gas can. drain gas from bottom little bowl though clean white rag check to see if water are rust powder catch gas clean white bowl like cool whip bowl. If anything there follow trail back to sourse. Water bead up in hand gas be flat any surface will work. Remember you have warranty but short.

RE: New Engine stops runing when I till for about 5 minutes

I have the same exact problem. The adaption of the engine is easy, but I added 20 lbs weight to give the tiller the same balance for handling. The engine starts easily and even when warmed up for 10 minutes, will till about 30 seconds and then the engine dies. It restarts immediately if I put the choke on, but dies very quickly again. I have tried leaving the choke on halfway, but it still dies in less than a minute. I believe the carburetor needs to be adjusted, but can find no information on line. I did find that this engine is a knockoff of a Honda GX200T1QXU 6.5hp engine, including the carburetor. HarborFreight will replace the engine, but I would rather see if working on the carburetor will solve the problem. The main jet is a fixed diameter and since the engine is used on competition gokarts, there are rules against opening the jet. Of course, I have no rules when tilling my garden. I found that this is a Huayi model carburetor, and available on Ebay for $24.99 + $8 shipping. So, I ordered one and will let this board know how well it works under load. I will also compare the main jets in each carburetor.

RE: New Engine stops runing when I till for about 5 minutes

I think I have found the solution. The engine is starving for fuel under a heavy load like a tiller and the throttle turned open 3/4 or more. Turn the fuel off with the fuel valve on the carburetor. I did this fix with the carburetor left on the engine. Remove the bowl from the carburetor and catch any gas in it with a catch basin. I found the main jet is located in the central tube visible when the carburetor bowl is removed. It screws out using a flat-bladed screwdriver. It takes about 4 turns to remove it. When the main jet falls out be sure to have something to catch it in or at least a clean floor. The main jet holds in a second jet called the pilot jet. I found the hole in the main jet was only large enough to insert a number 70 drill. This would be .028" diameter. The jets offered on go-kart sites show the jet should be .032" maximum for competition. So I drilled the jet with a #67 drill which is .032" diameter. Reassemble the carburetor putting the pilot jet in first with its smaller diameter upwards. Replace the bowl, keeping the off-center bolt lined up under the pivot for the float valve. Now my tiller operates without stalling and even sounds more eager for the tilling task right off the bat.

RE: New Engine stops runing when I till for about 5 minutes

Well folks, I believe I have finally solved the stalling Greyhound engine problem. When the engine is mounted on a Troy-Bilt tiller, it ends up at a backward angle of about 10 degrees from horizontal especially when tilling deeply. The engine is outfitted with a oil level sensor to make sure the engine oil does not run out. This is wired to the spark system by a single yellow wire. I blocked up the tiller wheels and let the engine assume its tilling position. It stalled within 15 seconds. It would not restart unless I leveled the engine. Opening the main jet helps on engine power, but does not affect the stalling problem. By clipping the wire to the oil sensor on the side of the crankcase, the engine does not stall. To make sure there was enough oil even for this tilted orientation, I filled the crankcase with oil until the H(igh) mark on the dipstick was just being reached (with the engine level).

Another idiosyncrasy I determined was that when the engine is tilted there is a possible internal binding that will cause the rope to reach a hard stop. I found this out the hard way. While in my test mode for the tilling position, I tried restarting the engine. When level, the engine would typically start with one pull. However, when tilted the pull rope was jammed so hard I could not the engine over even slowly. If I reached into the pulley at the back end and rotated the engine backwards it moved easily, but again hit a hard stop at the same point when I pulled the rope. I'm envisioning that the connecting rod has enough sideways play to reach an internal engine protrusion or possibly the crankshaft. I removed the engine from the tiller and returned it to the Harbor Freight store. The store manager pulled the rope and it turned over OK. Nevertheless, he replaced the engine for me with no question, but I'd almost bet I had returned an engine that was good. You just can't start them if they are tilted way back as on the Troy-Bilt tiller. You'll have to lift the tines out of the ground, first.

RE: New Engine stops runing when I till for about 5 minutes

After re-reading the thread, I see the first poster already determined the oil float problem. Therefore, I believe the solution is related to both clipping the wire to the oil float and drilling the main jet as described. My tiller now works fine on the Greyhound engine from Harbour Freight.

Incidentally, my earlier post on the replacement carburetor. When I received it, it was an exact duplicate for the Huayi on the engine and the same problem occurred without opening the main jet. For a while before I determined the oil level sensor issue, I was playing around with the carburetor thinking that was the problem with the tilted engine, however, now convinced it boils down to the oil level sensor AND the drilled out main jet.

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