# removing clutch on Ryobi 790r trimmer



## wa5ngp (Aug 14, 2010)

I am trying to repair the recoil cord mechanism on a Ryobi 30cc 790r string trimmer. I have gotten the clutch drum off the end of the drive shaft. Now I see a butterfly shaped casting (rotor?) about 3 in wide and 1/2 in thick that is either threaded onto the end of the shaft or press fitted onto the shaft. It looks like there is a brass collar between the shaft and the rotor casting.

Can someone advise if I need to unscrew that rotor casting or pry/pull it off? 

I've got to get it off to get to the recoil mechanism on the other side.

Don


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## glenjudy (Aug 26, 2006)

If you've removed the clutch drum, the next thing is the clutch itself.
Using whatever method you used to hold crank/piston still while removing drum, use same method to unscrew the clutch, CCW.
pay particular attention to sequence of washers and spacer(s)
hth


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## wa5ngp (Aug 14, 2010)

Thanks Glen. That's what I needed to hear. Turn the clutch CCW to get it off. I just couldn't tell if it was a press fit or threaded on. Now that I look at the clutch further I think its broken. The spring pops off as one long spring when I remove the drum instead of a closed circle spring that holds the clutch together.
Don


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## glenjudy (Aug 26, 2006)

If neither of the hooks on the end of the spring is broke, you ought to be able to put it back together.


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## wa5ngp (Aug 14, 2010)

*you gave me confidence*

Ok, now that I knew confidently what to do I got it off. I had to heat the clutch casting with a propane torch for about 2 minutes. Then after a hammer tap it broke loose. Maybe someone worked on it before me or maybe its just an old design because there were no washers or spacers under it. Pretty simple.

After I removed it now the recoil cord retracts ok. I think the clutch spring broke apart and was blocking the full recoil.

Here's what it looked like. Note the marking "out" on the casting as advice on how to replace it. 

Maybe I can heat the end of the coil spring to make a hook in them and then put it back together.

tks
Don


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## glenjudy (Aug 26, 2006)

Personally, I wouldn't fool with it anymore, if the inside of the drum is good, just get another clutch, the old one is too far gone.
The spring is a certain length. with a certain tension, it won't work as designed if you mess with it.
fwiw


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## wa5ngp (Aug 14, 2010)

Yes, I agree, its likely to break again at that spot. Furthermore, after I got into the recoil spring I found it broken due to rust so I think I'm going to set the whole thing aside for parts for some other project. It was an interesting project to learn how to get it apart. I've taken a few of these apart now. Its interesting how many slightly different designs there are all doing the same thing. 
don


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## Lawnmowertech (Nov 12, 2008)

Wa i have one word for that clutch its ouchy 

790r was one of the better ryobi trimmers made compared to todays yellow shaft ones 


if you need the clutch let me know i have some here 

calvin


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## wa5ngp (Aug 14, 2010)

tks Calvin,
I'v added your url to my bookmarks on repairs. 
I'm more likely to order a belt for my mtd lawn tractor when it starts slipping (again). I've got one of the variable clutch things that is finicky about belts.
Don


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## Lawnmowertech (Nov 12, 2008)

that url will be changing in a few months i will update my profile here when that time gets here also if you notice i mention im a Distributor for a Aftermarket parts manufacture this means those Modules you get called nova from rotary 

Oregon makes them and so does the manufacture i am a distributor for i get them cheaper thru that manufacture so i pass on the savings to the end user 

so the nova is just a name that rotary gave it its actually made in the same warehouse since they all are the same exact part 

But im putting a catalog for that product line together on my site it is located here 

http://www.cmsmallengines.net/cheap-small-engine-aftermarket-parts.html


its not completed so i am working on it there wont be any tires or blades since i cannot guarantee me making a good profit on bulky items 

the smaller items will be much more easier to ship etc. 

i will start on this probily tonight sometime need to add some items to the database

I may have the mtd belt in stock i have some old stock belts here in mtd and murray i want to get sold thats why i am going to put the #s on this site if its ok with hank


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## drb930 (Apr 29, 2013)

Anyone still monitoring this thread?
I have a 790r that I have had a love / hate relationship with for a long time.
Put a new cylinder on it years ago.
Cant get it to run now, wont even bark with starting fluid.
Carb leaks all the fuel out.
Seems like the spark is not strong enough?

Thanks,
Dave


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