Toro 22" Recycler GTS Personal Pace #20017 - Difficult start/restart / Governor adjustment - Tecumseh 6.5HP

[BGood]

In years past, our Toro GTS mower (see attached) would start reliably, but starting this year has been a non-starter. I tried cleaning the carb, then replacing the carb, and it still will not start relaibly. Thinking that it may be the governor linkage, I tried adjusting the governor arm according to the manual (see attached), but although it will start when the governor arm is adjusted per manual, it revs way too high and I instinctively kill the engine so I won't over-rev.

Can anyone tell from the attached picture of the governor arm what might be the problem? Thanks.

 

[Rivets]

This is what I recommend with those Tecumseh carbs. Remove the carb and tip upside down. Remove the bowl nut and make sure both the horizontal and vertical holes are open. Next, with the carb upside down check the float level is either parallel with the carb body or slightly lower on the side opposite the float pin. Reinstall the float bowl. Now remove the black plastic cover, next to the primer bulb, and you will see a screw. This is actually the idle jet and you can remove it to make sure the horizontal and vertical holes are open. Reassemble and test unit. May have to readjust the governor. This service manual may help you out. https://www.mymowerparts.com/pdf/Te...P-4-CYCLE-L-HEAD-FLAT-HEAD-ENGINES-692509.pdf

 

[sgkent]

the instructions seem specific. DId you hold the shaft with some locking pliers or something while holding the throttle all the way open with the arm, and lock the pinch bolt? If yes, don't know what to say except maybe hold the shaft all the way, loosen the pinch bolt and back the arm up a little. Keep doing that until the RPM is around the proper spec, which will depend on the blade length. I think that Toro 21" blades are around 3200 +/- 100 RPM. Max legal speed is 3456 RPM on a 21" blade. Most are under it. 19000 feet per minute at the blade tip is the max legal speed so to get there you have to do a little match to back into the RPM. Blade diameter X Pi X RPM \ 12 will give you the feet per minute. 21" x 3.1416 X 3456 RPM \ 12 inches per foot = 19000 feet per minute

 

[Rivets]

Sg, if you look at the picture and knew Toro mowers it is 22” steel deck model. To my knowledge Toro never used Tecumseh engines on their 21“ cast deck models.

 

[BGood]

Hey thanks for the helpful suggestions, Rivets and Sgkent. I spent the past couple of days working on this and think I finally resolved the carb, electrical, and governor adjustment issues.

As usual, I became impatient with trying to clean the tiny orifices of the original carb carb and installed the $10 ebay replacement I had previously ordered. I was disappointed that the new carb did not immediately solve the starting problem and went on to check out the ignition spark which was very difficult to see while pulling the recoil cord. With the spark plug out and my wife easily managing the compressionless recoil cord, I was relieved to see at least a weak little yellow spark and was encouraged enough to spend $4 on a new spark plug. I then followed the service manual guide for setting/adjustment of the governor arm, but somehow ended up with what seemed like an over-revving engine. That was when I sent in my original forum post.

Going back to the service manual and other internet sources in hindsight I think I misunderstood the governor arm adjustment instructions, or maybe was looking at the adjustment sequence for a different engine. So I went back to the basics of bending the butterfly spring tab and resetting the governor arm as shown in the service manual. By making incrementally small adjustments to the metal spring tab and governor arm, I was eventually able to get the engine to start and run at what seems to be a safer speed. Not having a tachometer I could only do this by ear. The adjustment rules I used were as follows:

• Bendable spring tab: Forward=faster / Rearward=slower
• Governor arm: Untighten screw / set arm vertical / governor plate horizontal; test; adjust plate clockwise (rearward=RPM+); very sensitive
• Butterfly screw: CCW opens valve (RPM+); CW closes valve (RPM-)

And by the way, if anyone is undertaking a carb replacement on this model engine, remember to remove the entire carb assembly from where the intake manifold joins the engine block. If you remove only the carb from where it joins the intake manifold (and don't have skinny 6" fingers) you will have a devil of a time replacing the inside carb nut. I had forgotten about this and spent an extra hour getting the inside nut started.

The attached photos of the bendable spring tab and governor arm show the alignments which seem to work for me. Thanks again for taking the time to respond to my request for help.