# 212 Predator Adjustable Carb Project



## Waterlooboy2hp (Nov 29, 2011)

After reading lots of things on the internet, about re-jetting 212cc engines for running in cold weather, I thought, why not open up the stock .028 HS jet and make it adjustable. 

One thing puzzles me. A 212cc Predator, with a stock .028 jet, runs fine in warm weather (above 40 degrees). The only change, seems to be the introduction of winters cold air into the carb. It seems that the idea of a heat box would solve the problem, without changing to an increased jet size.

Getting warm air to the carb might be the answer. I am working on a prototype to do just that, without the use of a heat box. In the meantime, I thought that being able to fine tune the high speed jet, might be a good idea also.

I bought this carb to test my idea. It already has the adjustable low speed jet.









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I got an M8 x 1 bolt, so I could match the threads on the bowl nut. I dug through my old carb parts and found a needle assembly, that I could adapt with the fiber washer seal.









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On my lathe, I turned the needle assembly threads down to .200, to be silvered into the hole, that I drilled part way in the head of the M8 bolt. Then drilled a clearance hole (.136), the rest of the way through for the needle.









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Once I had it silver soldered, I tested it in the carb and found that the needle was not quite reaching the jet. Had to thin out the bolt head, from the bottom. 









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The completed set-up came out fine. 









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The HS jets seem to run from the stock .028, all the way up to .048. Not sure how much I should drill out the HS jet to. I guess I could go all the way to .048, as the adjustment will cover all of them.

Just put a 212cc on my Jake 626, and will test this carb on it this week. -- John


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## dbert (Aug 25, 2013)

John
I love your work. I knew before I opened your thread I was going to be impressed.


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## SlowRider22 (Oct 17, 2013)

Outstanding!
Once you fine tune everything, you'll have a great product. Start selling them to all the folks who have a predator engine.
Let us know how things work out


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## Waterlooboy2hp (Nov 29, 2011)

Waterlooboy2hp said:


> After reading lots of things on the internet, about re-jetting 212cc engines for running in cold weather, I thought, why not open up the stock .028 HS jet and make it adjustable.
> 
> One thing puzzles me. A 212cc Predator, with a stock .028 jet, runs fine in warm weather (above 40 degrees). The only change, seems to be the introduction of winters cold air into the carb. It seems that the idea of a heat box would solve the problem, without changing to an increased jet size.
> 
> ...


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I ended up using a #56 drill (.0465) to open up the HS jet seat. I got time today to go ahead and install the new carb, with adjustable high and low speed jets. 

At the same time, I had finished up my idea for getting warm air to the carb intake, without the use of a traditional heat box. 

I had started with a small piece of 1" electrical conduit and added a flange. Next, I found an old choke shaft and used the plate from an old throttle shaft, that just happened to fit perfect in the tube. This damper control is more for testing, than for anything else. 

When cold weather gets here, I want to be able to run the engine without adding warm air to the carb intake and see if adjusting the new HS jet is enough to smooth out the engine. If not, I can open the damper and introduce the hot air, and take it from there.


















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I added a hole to the side of the muffler guard, that was 1/4" larger in diameter than the flange pipe. (I did not want the pipe to touch any part of the muffler, or its cover). I also put a 1" hole through the side of the carb cover. (both inner and outer walls).

I bolted the flange pipe directly to the carb cover at first. I wanted to see if anything was going to melt. After 1/2 hour of run time, nothing had melted, but I could feel a tiny hot spot on the plastic. It was right next to the flange, at the very top. Turned out, that there was a pocket between the two cover walls, that trapped the heat.

To be safe, I put a piece of .062 Phenolic between the flange and the cover (it can be seen in the 1st photo). Also cut away a spacer between the two walls and added 3 layers of the Phenolic, to fill the void. Now the heat would not get trapped in the pocket. 










I can`t really test the system out, until we get some cold weather. Right now, with the damper open, the hot air mixes with the normal incoming cold air. If need be, I can always stuff some filter foam, into the holes where the cold air comes in, to restrict it more.

The overall set-up is nice and compact. Time will tell if it works , or not. - John


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## nt40lanman (Dec 31, 2012)

Impressive detail work!!! Why didn't you thread the inside of the bolt and just put the needle in there?


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## countryboymo (Oct 13, 2014)

Beautiful work!


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## Waterlooboy2hp (Nov 29, 2011)

nt40lanman said:


> Impressive detail work!!! Why didn't you thread the inside of the bolt and just put the needle in there?


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That style of needle has an o-ring on it, and would require a 1/4" hole to be drilled down into part of the bolt thread. No material left to support the bolt threads.

After making the first one, I found a style of needle in my stash, that will work with just a thread in the bolt. The seal is still an o-ring, but needle spring pushes it against the head of the bolt, on the outside. It can be used in the bowl bolt that comes with the carb, or an 8mm bolt from the hardware store.










As carb needles are expensive, even if you could find one of the right type and size, I have now refined the whole process a bit further. I am going to make some needles from #10-32, stainless steel Allen cap screws, that have a partial thread. They were shipped to me today. The o-ring, washer and spring are easy enough to find.

Prototypes pave the way for improvements. -- John


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## nt40lanman (Dec 31, 2012)

Makes me wish I had a lathe


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## rhenning (Sep 19, 2013)

So did you test it out yet?? Roger


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## Waterlooboy2hp (Nov 29, 2011)

rhenning said:


> So did you test it out yet?? Roger


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As far as the adjustable carb jet, it works like a charm. The engine runs so smooth, that it sounds like an electric motor. It was 80 degrees that day, so I suspect it is adjusted to be pretty much the same as a stock .028 jet would be.

I will have to wait for some temps well below 40 degrees, in order to see how adjusting the high speed jet and feeding warm air into the carb will work out.

In the meantime, I am preparing to make some 10mm to pipe thread adaptors for extending the oil drain plugs. I am planning to make them from 5/8" aluminum hex bar stock. I ordered some material today. -- John


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## Waterlooboy2hp (Nov 29, 2011)

Waterlooboy2hp said:


> ========================================
> 
> As far as the adjustable carb jet, it works like a charm. The engine runs so smooth, that it sounds like an electric motor. It was 80 degrees that day, so I suspect it is adjusted to be pretty much the same as a stock .028 jet would be.
> 
> I will have to wait for some temps well below 40 degrees, in order to see how adjusting the high speed jet and feeding warm air into the carb will work out.-- John


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Well, it was 28 degrees this morning, so I thought it might be a good time to test my adjustable high speed jet and warm air intake, on my snow blower.

I started up the Predator engine on the snow blower with the hot air damper closed. As I expected, it was hunting pretty badly. I let it run that way for a bit and then opened the high speed jet 1/4 turn. The engine smoothed right out.

I then turned the needle back in 1/4 turn and the engine returned to hunting. I opened the damper on my hot air intake and the hunting began to subside. With it still hunting somewhat, I blocked the cold air intake holes with my finger. The engine stopped hunting and again smoothed right out.

I will stuff some foam filter material into the 4 cold air intake holes to restrict the flow of cold air. This will force the carb to pull much more warm air off the muffler. 

I think either method, will solve the hunting problem by itself. I have both systems in place, so I will leave it that way. A little overkill doesn`t hurt. -- John


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## detdrbuzzard (Jan 20, 2012)

too bad those predator 6.5 motors don't have an electric start option. I would buy one and do some of your mods. didn't another member make a heater box for his predator motor


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## Waterlooboy2hp (Nov 29, 2011)

Waterlooboy2hp said:


> ===================================
> 
> Well, it was 28 degrees this morning, so I thought it might be a good time to test my adjustable high speed jet and warm air intake, on my snow blower.
> 
> ...


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I got the final version of the adjustable high speed jet done. Got all my tooling ready, so I can make a run of about 25 units. This is what the final product looks like. 




























I am also going to make up some of the 7mm x .75 Brass seats, to go with the adjustable units.

Will be adding one of these to the Predator 212cc engine on my new generator, as well as the Predator 346cc engine on my American Lincoln snow blower. -- John


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## 43128 (Feb 14, 2014)

are you going to be selling these? i and im sure many others would gladly buy one from you


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## HoldingHeavy (Mar 18, 2014)

43128 said:


> are you going to be selling these? i and im sure many others would gladly buy one from you


I would definitely be interested in purchasing if you decide to sell your ingenious setup.


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## pfn (Dec 24, 2010)

HoldingHeavy said:


> I would definitely be interested in purchasing if you decide to sell your ingenious setup.


I like one as well should you decide to sell any.


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## Prof100 (Feb 9, 2015)

Very impressive work on the adjustable needle and hot air box. I see the adjustable needle is available for the Predator but what about the hot air box?


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## ChrisJ (Nov 27, 2014)

Absolutely beautiful work John.


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## demigod74 (Dec 23, 2014)

The company that makes predator engines should pay you to engineer their engines to work on snow blowers


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## dbert (Aug 25, 2013)

pfn said:


> I like one as well should you decide to sell any.


Perhaps John doesn't want to risk posting for commercial gain, but is it ok if another member does it because he thinks the guy is very talented?

Search ebay for HF Predator Engine Adjustable High Speed Needle Assembly, or just search for seller waterlooboy2hp.
Del


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## nt40lanman (Dec 31, 2012)

Found it. John, that's too cheap!!!!


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## FearlessFront (Aug 18, 2016)

I'm glad they make an adjustable main jet for these engine's. Because I have an Ariens that I run as a snowblower in winter and a mower in summer, so I need to be able to just adjust it for spring and mowing and back again for winter and throwing snow. I just ordered two of those and I cant wait to get them and put them on. Adjustable main jets are unheard of on engines today, and the Predator engines are excellent and the best prices around, so the fact you can add an adjustable main jet, just makes those engines that much better....


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## Dauntae (Nov 10, 2016)

Hmm I wonder how well they would fit on other Honda clone engines, might have to order one just to see.


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## FearlessFront (Aug 18, 2016)

Dauntae said:


> Hmm I wonder how well they would fit on other Honda clone engines, might have to order one just to see.


I have a feeling they would work just as well, because they all basically use the same carburetor.
Let us know if you do, because I have a minibike that has a honda clone that is not a Predator and their have been times I wanted to adjust that one too.
Or if I get a chance I can try it on my non predator clone and let everyone know how it work's, but I do believe it would work perfect because they all are the same type of carburetor and it says in the ad, will work on other engines too, but does not go into detail about other engines.
I wonder how these adjustable main jets would work on a real Honda engine, not that a real honda needs much adjusting, but I do wonder if it would work on one of them too. If they also use those same style carbs I would think they would, considering all of these clones were based off a honda......


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## Dauntae (Nov 10, 2016)

I'll have to compare the carbs but the 254cc carb looks to be the same as the 208cc it replaced except the jets are different, Will have to check the bore of the carb but believe they are the same.


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## Backtroller (Aug 16, 2018)

Great information in this thread. Thought I would bring it back up to the the top. This answers many of the questions I had about running a Predator on my toro snowblower.


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## jpm45 (Aug 28, 2020)

For the 212 engine running at higher elevations, will this work or are the jets too big? +/- 6000'


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## dbert (Aug 25, 2013)

Welcome to SBF jpm45.
For most of us the stock jet runs too lean (EPA requirements). The beauty of an adjustable mixture is to create an orifice that works best and provides the most power for whatever temperature and altitude its being operated at.
Have you tried running a stock predator jet? I'm just thinking if they are typically too lean for those of us at lower elevations it might work well at 6000 ft.


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## crazzywolfie (Jun 2, 2014)

here is a link to one i found on ebay. i have saved it for the day i might need one but for $50-60 shipped i really don't see me ordering one. my machine runs fine with no surging like it is lean like my neighbors. i got a couple neighbors with slightly newer machines that surge up and down until they are put under load. 








Adjustable High Speed Needle Predator, Honda, Kohler, Powermore, Briggs&Stratton | eBay


Find many great new & used options and get the best deals for Adjustable High Speed Needle Predator, Honda, Kohler, Powermore, Briggs&Stratton at the best online prices at eBay! Free shipping for many products!



www.ebay.ca


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## 140278 (Aug 27, 2020)

the same person from new jersey sells it for $29.99 USD that's $39.30 CD yes it a ouch for the way north guys when you add in shipping and taxes


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## HillnGullyRider (Feb 9, 2014)

Why not just put a Tillotson on (they are only 40-50 bucks) instead of messing with chinese carbs (which are meant for only one thing, Bolt on, run it til it dies, then throw in the landfill).
Tillotson

_The TF-1A-6U uses our new TillotsonTCT fuel system technology to provide a substantial upgrade in performance to standard carburetors. It is our semi-universal configuration that can be used on gasoline-only engines. It is packaged with a variety of swap-able throttle and choke levers to fit a variety of applications (see photo). It can be used to replace Ruixing, Jingke, Huayi, Kinzo and Wisdom carburetors used on Chinese brand 5.5 – 6.5 (160-212 cc) engines commonly used on generators (Champion, Generac, and others), and Toro, MTD and other lawnmowers. Check the bolt pattern and choke levers show in the pictures below for compatibility. _


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## tabora (Mar 1, 2017)

Some day soon, EFI kits like this one will probably be a common solution for this issue: small engine EFI | ECOTRONS


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## crazzywolfie (Jun 2, 2014)

but with what efi costs i doubt it will ever be cost effective over a carb. $1000+ for efi or $50-100 for another carb or an adjustable main jet. only way i could see efi on small engines catching on is if they somehow manage to make a kit for about $2-300 but i don't know if i see that happening. also they don't even know what common issues they will have with efi yet but i bet they will have lots of bad fuel pumps since most people tell you to run the engines out of fuel which most electric fuel pumps do not like. once the oil has been washed off the internal parts if needs to stay lubricated or they generally lock up.


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