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Hard starting Lawnboy engine


Englbert's Avatar
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Join Date: Sep 2009
Posts: 3

09-27-09, 02:20 PM   #1  
Hard starting Lawnboy engine

I also have a 6.5 Gold series Lawnboy mower, I also had problems starting the engine. I seemed to always flood, the plug would be wet and I would remove the plug and dry out the cylinder and warm up the plug with a hand torch. I had replaced the carburator etc. Still wouldn't start. On a 2 cycle engine, compression seems to more critical. I just finished replacing the piston and rings. The original rings were stuck in the grooves and had lost compression from just plain wear. In my case, the cylinder wall was not scored. After replacing the piston and rings, I now have very good compression and the engine started on the first pull. If you pull on the start rope and there is little resistance as the engine turns over, this may an area that you should also look at.

 
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Airman's Avatar
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TN

09-27-09, 06:17 PM   #2  
Please post the model and serial number.

How much compression does it have?

Have you removed the muffler and cleaned out carbon?

Have you inspected the exhaust port for carbon?

 
Englbert's Avatar
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09-28-09, 02:17 PM   #3  
Hard Starting Lawnboy engine

The Model of the 6.5 HP engine is 10525, Ser # 8900949. I
do not have a compression gauge but compared this engine to another Lawnboy engine Model 10324 which I also own. This mower is newer and has not been used very much. By comparing the two, I determined that the Model 10525 had very lower compression.
I had checked the exhaust ports earlier and they were clear and did not need to be cleaned.
Having worked as a small engine mechanic in my earlier years, I found when the exhaust ports are plugged, the engine just does not have much power when mowing. The engine may start OK but the plugged exhaust ports act as back pressure on the engine.
Hope this additional information helps.

 
Airman's Avatar
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09-28-09, 06:04 PM   #4  
You really need to know compression or you may be wasting time. Borrow a tester or see if you can find a shop that will test it for a small fee. Toro says compression should be 80-PSI minimum for this engine.

Install a new spark plug

With the model and serial number, you can download an engine service manual as well as others from the Toro website.
https://lookup3.toro.com/request/request.cfm

 
joec2000's Avatar
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10-02-09, 12:40 PM   #5  
Not too familiar with this particular engine, but are the crankshaft seals good? Those are often overlooked items on 2 strokes.

- Joe

 
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