OutdoorKing Repair Forum Forums Repairs and Maintenance Questions on Trimmers and Brushcutters Ryobi Trimmers & Brushcutters Ryobi Lawn Hornet clutch removal & air leak

Evening all

Having trouble tracking down an air leak on a 1989 Ryobi (Ryan half crank). It ran fine for a little while (only just got it from the tip shop), then started making a hissing or whistling noise from cold starts (that went away when hot). Now there is no noise from cold, but a really loud hiss (near scream) at all throttle openings when hot. When restarted, it takes 10-15 seconds to start whistling.

checked all the gaskets, put oil around them to see any air leaks, none noticeable. I'am trying to get the clutch off to access the main bearing to see if the seals are the issue.

I have tried the T20 (maybe 25), and it tore out the middle of the screw head on the clutch drum. I have put some wd40 in around the head and will try again in the morning, but I don't want to damage the head any more. Whoever installed the clutch must have used tonnes of loctite or something.

Bear in mind the clutch is in good condition, so angle grinding, etc isn't a option.

Have done it twice on near identical old Ryobis before without issues, but this one has stumped me - i just can't get a good grip on the retaining screw.

Any advice would be appreciated

Thanks
Tyler

Hi Tyler, I don't know how you can go wrong on those star screws, provided you use the correct tool. They give a very positive grip. I had to remove the clutch on one of these for the first time, after my dad borrowed it and part of his shirt got sucked into the fan which sits behind the clutch, and bent the starter pawls, makng the starter unable to turn the engine over effectively.
I had to purchase a T20 (I think it was T20) screwdriver for about $8.00 in order to undo that screw in the centre of he clutch. One modest yank of the wrist, and it cracked with ease and undid.
I found pieces of blue shirt material in the fan blades and the force had bent the pawls, or whatever you call them, so It was just a matter of undoing another similar unit and swapping over it's pawls and it was back to work. These Ryan/Ryobis are rugged and easy, if a bit fiddly (like all small engine powered garden implements), to pull apart and fix up. They seem to place emphasis on torque , rather than power, as they are made to operate some pretty heavily loaded machinery, such as the garden tiller and blower vacs, as well as weed wacking.

And that's exactly how the other two have come off Mowerfreak. This one, I had the right size T20, ensured it was fully in, gave it a bit of a twist, and then a little bit more (just with a handle, not a 2m breaker bar or anything silly), and it just ate out the screw head like that. I don't know what the previous installer did (the clutch looks less than 5 years old), but they have really stuffed me up.

The Ryans are a really torquey motor and have tonnes of pull down lower in the rev range, but sometimes seem a little low on top end power for a 31cc. Still a great motor though.

Tyler you might have to try a T20 bit in an impact driver, surprising the difference the impact makes. Over the years I have made up a lot of adapters to hold various allen keys and torx bits so I can use them in the impact driver.

If this is String trimmer/Brushcutter setup it is a T20 but most of the T20 drivers I able to get will not fit through the neck of the clutch drum and would need modifying to do so which have done as I do use it a lot. Now at one time they did put red Loctite on the threads and if so it will be a pain to get loose. Sometimes you can shock it loose by the bit in place smack it with a hammer. But before you do this get a light to shine down shaft and what damage you have done to the screw head. At this you might fine that there is slot in the head too; sometimes there is one, other times there is not. If so then a hollow ground flat tip will work at times. Even this type driver you will need to grind the shaft above the tip to get it in place. as you will want to have as much of tip engaging the screw as you can. You want the flat tip just narrow enough to pass diagonally thru square neck but shaft will need to even narrower to pass the square shape.

Sorry I can't give the exact of the flat tip tool as I lost mine in the 2014 move but at least I remember how I made it if I ever need it again.

May have to sacrifice the clutch drum shaft and cut it off as low as possible to access the damaged screw with alternative tools. Then get another off a wreck when it's time to reassemble.

I think I worked out half the problem. I believe the clutch is Chinese made out of the weakest steel they possibly could. i stuck a very small screwdriver down it and i was literally able to scratch a trench in the screw head with no damage to the screwdriver