GT225 using bigger string

[PTmowerMech]

My landlord wants me to weed eat around her pond. Especially that thick stuff that grows just inside the water. She's got a Briggs trimmer on wheels, that works pretty good. But it just kills my back after about 10 minutes, on the high sloped side. So I broke out my GT225, but the string doesn't last very long. So I found some thicker string, but it reduces the performance of the engine. Can I adjust the high side of the carb to help with this?

It shows 10,000 RPM max. I'm at about 6K with the thicker string at full length.

Or is this a no no for some reason I haven't thought about?

 

[bertsmobile1]

Watch the muffler & the drive
Running under heavy load that reduces engine speed causes carbon build up
On strait shafts it chews through the bevel gears
On bent shafts the drive shaft tends to come loose at the swages either end
Consider a solid blade the smallest diameter that will fit or fit a dragon fly head with precut line
Use a shorter length of thicker line or get a Tanaka manual head ( called ashtray by techs ) and again only lay out a short length of line

 

[Hammermechanicman]

I assume you went from 080 to 095. If you move the line cutter so the line is an inch and a half or so shorter it will get the revs back and perform a little better. 21cc motor not going to knock your socks off.

 

[PTmowerMech]

I noticed that the shorter the line got, the higher the RPM's would get.

Yes @bertsmobile1 , it's a bent shaft. I noticed today that there was some grease coming out just above the head.
Can I adjust the carb up to about 9000 rpm with the thicker string?
I was using a .105. Now using a .130

 

[StarTech]

The Echo 21 cc trimmers are gutless wonders. As with even .080 line they only peak out on max between 6900 and 8100 rpms, depending the version of the GT225. Even then you need to drop the max rpms by 20 rpms by tuning a little rich per my carburetor tune up chart here. If you want more speed switch to a SRM-225 which can peak out around 10K.

BTW bent shafts are not design for brush cutting. IF you keep up trying you will destroy the drive shaft. They are meant for light grass trimming. I got two Stihl FS80 brush cutters in the shop with broken flex drive shafts where they twisted in two. These flex shafts are $39+ each (cost). And I am repairing another FS55 gear box where they left it out in the weather and the bearing locked up. At least the idiot that was trying to fix it didn't it running as the muffler spark arrester was Orchard Wasped.

 

[Hammermechanicman]

I noticed that the shorter the line got, the higher the RPM's would get.

Yes @bertsmobile1 , it's a bent shaft.
I was using a .105. Now using a .130

080 to 105 and now 130. You will probably kill it.

 

[StarTech]

That sounds like PT is screwing those neck bolts too tight again. Referring to his avatar.

 

[Hammermechanicman]

"Some is good, more is better, too much is just right."

 

[PTmowerMech]

Ok, thanks for all the info. My bright idea just got real dim. But you guys probably saved me from destroying the unit. Thanks. I'll just have to figure out how to do this pond with her trimmer on wheels, and not take out my back.

 

[StarTech]

You really wouldn't like the old Ryobi 4 cycle bushcutter that I hated and the Red Max EB8001 backpack blower. Both are heavy as can be if you use either very long. I could only do about 1300 ft of fence line with the Ryobi with harness before my back gives out.