Fixed A Small Problem

9 years ago

On my 2004 Lawn-Boy 'Insight' 10684 mower, its been running slower and kind of 'hunting' in RPM for several years. I just did my spring 'fix-up' on it (clean, change oil, air filter, blade, etc.) and it looked so good I decided to take a look at the governor system. Manipulating the throttle on the carb temporarily corrected it so I knew it was the governor. IOW, holding the throttle lever wide open resulted in strong engine acceleration and smooth running. All I did was to take a large screwdriver and very slightly bend the tab forward where the front end of the governor spring attaches, increasing tension on the spring. Even a very small adjustment to this tab has big results, so my first try yielded about 3600 RPM (guessing). It had a very fast top ground speed too and would spin the wheels. :) I tweaked it and I think I'm about 3400 or so and it runs strong and smooth. The tab was visibly leaning to the rear when I started and now its vertical, so I think I got it back to about where it belongs.

Much better mowing, a little faster ground speed if I want it, much better bagging and no up and down RPM. I think it probably was below 3000, maybe around 2800 or so when I started.

BTW, I have been using SAE30HD in it for the whole time but I just changed to Castrol SynTec synthetic 10W-30. Seems to like it fine, nothing unusual cropped up. Now I am using the same oil in both mowers which is better.

Anyway, just posted in case anybody else still has one of these 195cc Tecumsehs that is running a little slow. I don't guess there are many of them around. Since I've been using some Marvel Mystery Oil and stabilizer in the gas for about 10 years, I have pulled the carburetor orifice/bolt a couple of times and it was perfectly clean. That was actually where I first thought my trouble was and I was kind of stumped for awhile until I just decided to do something and see what happened. Its literally like a new mower.

It still has the original spark plug too. I knew that wasn't the problem because it ran right when I manually worked the throttle.

Sort by:Oldest

Comments (4)

1saxman
Original Author
9 years ago
Actually I'm going to turn it down a tad - seems to be running a little too fast but it really is fun to turn this big motor loose. I guess its probably doing about 3600 to 3700. I'd like to see about 3450 which is still over the blade tip speed limit but not by much. I did my Honda engine one too but I only wanted a little more out of it, not a lot. In that case with a different governor arrangement, I just tweaked the spring to get a little more throttle.

One thing I go by is ground speed; both mowers have Toro Variable Speed, and you want the ground speed to be a fast walk with the bail hard against the handle. If you almost have to run, it's running too fast. I also just go by the sound - I grew up in the days before the blade tip speed limit and the rotary mower average RPM was around 3600. That sounds fast today and is really unnecessary and a little dangerous due to velocity of ejected objects.

Anyway, I actually have a tach but have never used it. I will get it out and let you know exactly what the speeds are - I'm anxious to see how close my ears are. Its the kind of tach that reads the rotation speed instead of going by a physical connection. I have to put a reflective spot on one end of the blade and 'shoot' through the discharge port.
1saxman
Original Author
9 years ago
last modified: 9 years ago
Okay, my ears need calibrating; the actual RPM is 3300, which is fine in every way. Must have been under 3000 before, going by the sound difference.
Related Professionals
Cincinnati Landscape Architects & Landscape Designers · Danbury Landscape Architects & Landscape Designers · Palm Desert Landscape Architects & Landscape Designers · Chatham Landscape Architects & Landscape Designers · Pine Bluff Landscape Contractors · Flagstaff Landscape Contractors · Orange County Landscape Contractors · Amarillo Landscape Contractors · Bozeman Landscape Contractors · Jackson Stone, Pavers & Concrete · Plainfield Stone, Pavers & Concrete · Niles Stone, Pavers & Concrete · Albert Lea Stone, Pavers & Concrete · Willmar Stone, Pavers & Concrete · Amherstburg Stone, Pavers & Concrete
Ted (Zone 4) IA
9 years ago
last modified: 9 years ago
The inductive combination tach/hobbs meter are pretty slick and only about 8 bucks delivered. No tape or anything like that.

Supposedly on a LawnBoy proper RPM corresponds with a certain high E or A or musical note or somesuch. Good RPM and sharp, balanced blade, good compression etc, sure makes the job more enjoyable and a better cut, especially in tall grass.
1saxman
Original Author
9 years ago
Putting on the reflector is no big deal. The tach I got is designed to measure the RPM of anything, not just mower engines.