# 1978 Craftsman GT 19.9 Engine Pulley Question



## NickM (May 3, 2014)

Hey there y'all!

I am a real sucker for old things, especially old mechanical things. I picked up a new to me 1978 Craftsman GT 19.9 Six Speed lawn tractor last summer and it worked great. I have the deck to a 917.253592 and believe my model number for the actual tractor is 917.257080, though I have not seen this anywhere on the tractor.

Anyhow, this year, after replacing the mower deck belt, (outer mandrel to outer mandrel to center mandrel), which broke while in use, I discovered that the engine drive pulley will not turn the deck blades when the clutch is engaged.

The mower ignites like a champ, but there is a squeal and smoke at the belt (when the belt--engine to deck--is too tight) when the blade clutch is engaged. 

I have ensured that the deck blades are free and turning ok, and I believe I am in the "sweet spot" for tension at the Idler Shaft Assembly adjustment, which controls the tension. According to the manual, for the 917.253592 model at any rate, it says you should be able to pinch the belt together with forefinger and thumb without too much effort.

Roger that. Done.

Once I did so, the squealing became minimal when the clutch was pushed down but still nothing is engaging.

So I then disconnected all the belts and turned the engine pulley by hand to see if that is where the problem lies. It will turn freely for a bit and then it gets real stiff and needs to be forced through the turn. It frees up again and then continues the same behavior.

So, realistically, what I am looking at here? Could it be the pulley or is there something elsewhere, such as attached to the clutch that engages the blades, that I need to assess? 

As far as running the tractor itself, it's fine so far and will drive without a problem at the moment, so that makes me scratch my head when looking at the pulley. The one part turns but the other will not when engaged.

Anyhow, sorry for rambling. I appreciate any thoughts here. I love this machine. It is extremely powerful and I want to see this old horse return to its former glory, if possible!

Thanks, and thanks for this great forum! Glad to be here!


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## jhngardner367 (Apr 5, 2011)

The stiffness is from the engine compression,and is normal.
It sounds as if you have a pulley that's going bad on the deck. Check them for spinning freely,with no binding,or grittiness.
Also, check to see that the belt is installed properly,and is the right part.


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## ftorleans1 (Jul 12, 2009)

Sounds like a bad pulley at the mower deck engagement clutch pedal, A worn tension spring at the mower deck engagement clutch pedal, worn or wrong engine to mower deck belt. The engine pulley is suppose to do what you have decsribed! Engine compression is making the pulley hard to turn. If you remove spark plugs, It will turn and turn...


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## NickM (May 3, 2014)

Guys! Thanks for your input! Sorry I have been away from this thread. Right after my mower went down, my minivan went down, and so I have been playing mechanic with that. Thankfully I can afford to have my lawn cut to hold me over, but it is definitely not preferable.

I took the belt deck off and when I spun the mandrels with the deck vertical (blade tips pointing towards the ground) I discovered that one of them felt like it had rocks inside. Interestingly, it didn't make any noises while on the mower. 

So I discovered one problem. My intention is to rebuild the mandrel. I found a tutorial somewhere on how to do it. When I get to this project. I will post the results.

In any event, thanks for taking the time to get me up to speed gents! It is greatly appreciated!


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