TOPIC: Small engine Grooving

OK, so I don't have any info on recent small engine Groove jobs. And- I ought to have put this in the Other Engines topic category, but you guys will get this just the same. Things that use gasoline but don't drive on the road. Lawnmowers, chain saws, boats, snowmobiles, generators, ATV's. Well, OK, ATV's can run on the road... But I encourage Gadgetmen to consider applying the Gadgetman Groove to these small engines. There are bazillions of these engines all around us. Look thru the Index for examples already posted before, some of the highest percentage economy gains have been on these engines!! I think Dr. Dude is the last person to mention Grooving a small engine, a Snowblower I think it was. My very first Groove on a running engine was my lawnmower, and it ran smoother after I Grooved it. I never did any fuel economy testing on it, as the lawn where I live isn't so big. Ron has always told us to practice on a small engine first to get familiar with the technique, good advice.

Along with doing the Groove, you should also consider opening the spark plug gap as well. Ron has a video I believe on his Groovy Service Bulletins youtube channel, in which he demonstrates the plug gap increase on an ATV or riding lawnmower. That video proves the point of the plug gap mod(which has always worked well for me on any engine).

Doing the Groove and plug gap mods to small engines is simpler than on a car or truck, no computer or sensors (in most all cases) to think about. So, if you are relatively new as a Gadgetman, or are thinking of getting back into it, or want more experience, but on something simpler than a car, look around. You could also help the environment with this as well- many small engines are gross polluters! You have the tools to make that un-burned gas that stinks up the exhaust, burn IN the engine instead!

I bet Ystervark could clean up with this in SA, and get use from his Small bit too!







There above are 3 examples of what the Groove can do on a small engine, Gadgetmen Take Heed!!

Tracy G

Morning Tracy.

Interesting that you mention me in this thread. I just finished grooving 2 lawnmower. Amazing results on the one. The other one we will test today.

For a start. The owner has 2 identical lawnmowers which he uses specifically for an 1 Hectare(About 2,5 acres in your language) plot that he maintains the grass on.

I did the one lawn mower first. We tested how long it can keep on mowing after the tap on the tank was closed. it was 3 minutes 58 sec. After the groove it went to almost 8 minutes on 1 carb of fuel. Now comparing the 2 lawnmower was another interesting one. The grass is not lawn like you think of it is like grazing grass for cattle. It grows very fast and is much harder to cut than lawn grass.

The 2 machines struggle to cut this quit a bit. You have to push and pull back and listen to the engine because it can bog down very easily. I did the groove on the one lawnmower first to compare. The one with the groove almost worked on idle and it seemed like it did not have a blade that is how smooth the engine was purring on while cutting. The other one was bogging down like always. The owner of the machines could not believe it.

Comparing fuel economy. The one with the groove had maybe 2 pints in to test. It ran for over 2 hours before it got empty and stalled. The other machine had 5 pints in and ran for 1.5 hours to empty tank.

I can tell you the owner is so stoked about this. It is an amazing feeling when you see someone who can't believe what is happening before his eyes.

So you can believe me when I say I will be going all out with the groove on the smaller engines. I grooved the second engine last night so we will see what happens with power and fuel economy on it either today or tomorrow. There is still a piece of grass to be cut on the owner's property that he wants to go do today or tomorrow. I will keep you all posted........

Bye the way. I used the medium bit on both machines and it worked like a charm.............

Oh man Martin, you go guy! This is awesome to read! Any chance you might get a pic or two of those Grooves? Wow you just pounded in the stake HARD in advocacy of Grooving small engines! AWESOME KEEP AT IT Buddy! thanks!!

Tracy G

Thank you Tracy for the vote of confidence............

I was going to create a new topic for the Lawnmowers but this is on topic and maybe just the right place to show the Photos. I mean I already posted most of the details here Ha Ha.








Both lawnmowers are mechanically exactly Identical. Only the colour on the body are different. Both lawnmowers are 30 years or older..............
Both have Robin engines on them.

The carbs are identical so it does not make sense to post both carbs here. I used the medium bit on both. Both smoked way less after the groove and the exhaust on both smell like hot air only. So I guess I did something right............









I did add some body with the standard putty that I use from day one. It seems like it was not needed though................

I was wonderin' about these 2 mowers. They look like any old Regular Joe lawnmower you might see anywhere. What is interesting on this Groove, is look at the ratio of Groove size vs. bore and throttle plate size. This is a huge Groove by comparison. And I wonder, it looks like the plate will simply throw air into that Groove up to a substantial throttle position. Did you say the mower will operate now under load at just off idle position? I'm salivating here, wondering if there is a big lesson in this one....?

Tracy G

Tracy to be honest I just did what I thought Ron instructed and that is to cut the biggest groove possible in any situation. If the Item IE TB OR CARB allows for a large greeve then use it...

yes these machines work at just of idle speed at the moment..........

You're right about that! OK so my obvious idea would be- for mower or other engines with a smaller bore size. Within practical limits, might we add epoxy to the outside of the carb body, to enable using say the Medium bit instead of a Small. I've never considered this till now. It seems to me that having the size Mikuni carb's those two mowers did allowed using Medium bit. I may need to score a junk small engine carb, to see if my exterior epoxy over-fill idea has any merit, as far as execution goes.

Glad I started this thread, maybe I kicked the right anthill for once!

Tracy G

Tracy.

You get amazing putties nowadays that will do the same job as the epoxy. believe me they set just as hard and they stick just as much. I did all my grooves with the putty it works like a charm......
Its much easier to work with...............No daming needed and so on. It stays where you apply it....

Also I remember Ron Saying something about the Bit size you use is only determined by the space you have between the Throttle plate and the bottom of the moulding.......Not by the thickness of the walls of the throttle body....
like in this illustration..........



Please correct me if I am wrong..........

I could not use the large bit because it did not fit between the pin holding the plate and the body...where I needed to cut.....I was afraid the bit would touch the steel screw....

you are exactly correct w/ this, Ystervark. Thanks for the Putty info, I will have to try similar stuff over here. On bit size/room to Groove etc.: A good example of a common 4 barrel carb over here is the Rochester Quadrajet 4 bbl carb. There just isn't room under the Primary throttles to Groove. The closed primary plates have only a fingernail of material left of the bores underneath to bottom of the base throttle body. And actually there are quite a few stock carb's of many makes that are unsuitable for different reasons. But there are also many that will work, as well. Just Depends...

Tracy G