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Discussion Starter #1
I have a cub cadet self propelled mower with the 173cc motor on it. The problem I'm having it sometimes it is very hard to turn it over to start. Some times it will kick back snapping the rope right out of your hand. Seems at times like it has more compression then it should. After it starts it runs fine. Wondering if you guys have any ideas what could cause this.
 

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Hi! Not sure what engine is on your mower. Might be beneficial to have a model and serial of the mower and any identifying info from the engine. Some of these 4 stroke engines have a pressure relief to aid in starting and if the valves are out of adjustment that can affect the timing of the pressure relief. I am sure someone with more knowledge of this engine will be along with the real answers. Bill
 

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It just sounds like a healthy 173 cc engine that maybe firing just a bit early during some start ups. I don't know much about Cub Cadets, or whatever engine is on there, Kawasaki? It seems like Bill might be on to something with the pressure relief being INOP, or intermittent. If not that then maybe the start phase of the coil is going bad, most of these solid state coils have a 2 phase (variable timing) for easy starting. It doesn't really seem like there could be anything else that could cause an engine to fire (kick back) to early, and yet run fine when it gets up to speed. Just my .02 cents.
 

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CC 173s are an MTD engine (Honda/Chinese clone). I have the horizontal shaft version on my MTD snow blower and it has been a first pull start very dependable engine for the last 6 years. I suspect the flywheel key is the problem or something that is causing the timing to be advanced. Roger
 

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Discussion Starter #7
Hi! Not sure what engine is on your mower. Might be beneficial to have a model and serial of the mower and any identifying info from the engine. Some of these 4 stroke engines have a pressure relief to aid in starting and if the valves are out of adjustment that can affect the timing of the pressure relief. I am sure someone with more knowledge of this engine will be along with the real answers. Bill
Model number of the mower is 94m. Cub cadet. The motor is made in China.
It just sounds like a healthy 173 cc engine that maybe firing just a bit early during some start ups. I don't know much about Cub Cadets, or whatever engine is on there, Kawasaki? It seems like Bill might be on to something with the pressure relief being INOP, or intermittent. If not that then maybe the start phase of the coil is going bad, most of these solid state coils have a 2 phase (variable timing) for easy starting. It doesn't really seem like there could be anything else that could cause an engine to fire (kick back) to early, and yet run fine when it gets up to speed. Just my .02 cents.
When I pull it over it has so much compression I can lift the front wheels off the ground. Once I get past that point it will pull easier, but that is when it will pull the rope out of my hand. The flywheel is clean etc. The mower has always been kept inside so no rust on the flywheel or anything.
CC 173s are an MTD engine (Honda/Chinese clone). I have the horizontal shaft version on my MTD snow blower and it has been a first pull start very dependable engine for the last 6 years. I suspect the flywheel key is the problem or something that is causing the timing to be advanced. Roger
I suppose if it isn't the flywheel key it would have to be the coil.
 

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Discussion Starter #8
Model number of the mower is 94m. Cub cadet. The motor is made in China.

When I pull it over it has so much compression I can lift the front wheels off the ground. Once I get past that point it will pull easier, but that is when it will pull the rope out of my hand. The flywheel is clean etc. The mower has always been kept inside so no rust on the flywheel or anything.

I suppose if it isn't the flywheel key it would have to be the coil.
I watched a video on this motor and I think I'm going to check the valve Gaps.
 

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I watched a video on this motor and I think I'm going to check the valve Gaps.
Good call, I've been on Youtube as well. If that doesn't yield anything check to see if there is a decompression valve that is stuck closed.
 

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Yes they talk about the valve adjustments being correct to properly operate the compression relief. Hopefully that is the issue. Bill
 
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Good call, I've been on Youtube as well. If that doesn't yield anything check to see if there is a decompression valve that is stuck closed.
Valve adjust seems to have fixed the problem. Intake was 006 and exhaust was 008. Set them both to 004 and it's starts right up and doesn't have as much rope resistance. Thanks everyone for your advice. Bought it used about a year ago and I don't think the valves had ever been adjusted.
 

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That is great news. Perhaps the compression release is tied to a proper valve adjustment. Bill
 

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Yes! Outstanding news, and thanks for updating us. I would imagine it runs much better now that the valves are opening and closing when they should.


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Discussion Starter #14
Starts with one or two pulls now. Yes it does run better and seems to be better on gas usage also. Thanks again everyone for your advise and help!
 
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