toro super R

Joined
Feb 14, 2017
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585
Location
iowa
does anybody know or have done an rpm bump to help the engine out a bit in thick grass. my unit has the toro txp engine model 20383. and overall it's been a good unit minus the lack of torque in thick grass. it bogs down a bit, and yes in this stuff I go slower and or use the side discharge. just thinking if I could give it a little more speed it would go through it a lot better.
 
agree... and all of my blades are sharp I rotate 3 of them during a season.....one is even a gator and truthfully it does no better at mulching then the oem toro ones...
 
Originally Posted by picman
Super sharp blade can be a big help.

Also keeping the underside of the deck clean.

You can bump up the speed a LITTLE by slightly bending the thottle linkage. If you overdo it the governor will start acting improperly and make matters worse. Do not mess with the governor.
 
Sharp blades help, you can bump the RPM up by using a tachometer ("tiny tach" is a cheap one) and bending the throttle linkage to put more tension on the spring. Most mowers that come through the shop aren't running fast enough. They keep the engine speed low due to blade speed requirements, but some of them are set very low. I usually put them at 3000-3200 RPM and they run great.

Here is a Donyboy73 video showing what to do:

https://www.youtube.com/watch?v=zyM4X24LgLk
 
I have done this twice, once on a Toro Recycler and on a cheapo MTD mower, in both cases the results were a significant improvement.

I did it by using some soft wire, think small twist tie with the plastic removed, to tie together a few coils on the governor spring. This allowed the governor to still perform its function, but the slight bit of added resistance on the spring brought up the RPM nicely.

I am not sure how much of a change I made on the Recycler model, as I never checked before and after, but gave it away to a family member in need of a more powerful mower a few years and about 100hrs of use later. They still have it today and it still runs well, but sees much less use and zero maintenance. I always ran it on M1 5w30 with annual changes.

The MTD has a small 125cc engine that was quite anemic in anything but thin grass and did not cut well even with a sharp blade. I used a tiny tach on this one and raised the RPM from about 2700-2800rpm up to about 3400 rpm. It now cuts well and has plenty of power to go through the thicker areas without having to rock it back and forth or pass over twice.

Other than it sounding like it was going to take off compared to running it at the original RPM, I have noticed that it seems to run about 20 - 30 degrees hotter oil temp using an IR thermometer on the back of the engine block after about 30 minutes of mowing, from about 230F to about 250F - 260F now, so I switched it to a straight 30w oil from the 5w30 I was running. I have not tried using it for a longer mow, as I have a riding mower now to do the larger areas, but it has been running like this for about 3 years now, probably about 25hrs of use. Always starts on the first pull.

As I believe was mentioned, its a good idea to calculate your blade tip speed. I went with 3400 on the MTD based on a 19" blade to keep the speed to about the recommended 17k fpm for commercial mowers. FWIW, I am not condoning raising the RPM, nor would I want to exceed a 17k or 18k fpm blade tip speed for safety reasons, just sharing my experiences.
 
Originally Posted by Lubener
Originally Posted by picman
Super sharp blade can be a big help.

Also keeping the underside of the deck clean.


With the Super Recycle I found this to be very true, especially the 3 little kickers that direct the grass back into the blade for further cutting. The accelerator blade pushes the grass down evenly so you get no clumping, as grass builds up on these parts it becomes less efficient and doesn't process the clippings like it should which bogs it down, the only solution is to walk slower.

I hose the underside down every time I mow, and don't bother with the wash our port, it doesn't do a good enough job.
 
I have owned a few Toro SR's over the years. Fantastic mowers! 100% what others have said about super sharp blades and the deck needs to washed after every mow. Also, try to mow when grass is dry. All the kickers under the deck must be clean.

Dave
 
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