# Toro powermax 8/24 oe, re jetting carb.



## dcinma (Dec 13, 2017)

Just bought this new. Work great but under heavy load it seem like it's running lean, adding some choke helps a bit.
This has the Loncin 252 cc motor, can I re jet it like people do to the Predator engines.


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## tpenfield (Feb 24, 2015)

Probably can re-jet, but potentially voiding the warranty is a concern. Maybe just run the choke a little bit.


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## dcinma (Dec 13, 2017)

I'm wondering if all these new "green" engines do this .
I'm use to old machines with mixture screws.


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## Kiss4aFrog (Nov 3, 2013)

It does seem the newer "green" machines with the non adjustable carbs are a bit leaner.
Being new I'm not sure I'd mess with it. But if you chose to pretty sure the Loncin is a clone and would use the clone jets. I just don't know what the starting point for a 252 cc is.

You could also get a drill set and try that. I got mine off Amazon. Amazon.com: AUTOTOOLHOME Precision Pin Vise Copper Hand Drill Set with 20pc Micro Mini Twist Drill Bits Hobby Model Rotary Tool for Wood Jewelry Plastic PVC 0.3-1.6mm: Industrial & Scientific


.


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## LouC (Dec 5, 2016)

If I was going to start fiddling with it I might buy a spare OE carb if not too expensive. My Briggs generator with the B&S Vanguard 9 hp is similar it has a bit of lean surge when not under load. I changed the plug and its not excessively lean so I left it alone. 
One reason I kept my old 2 smoke single stage, on these while they say the Mikuni is not adjustable you can actually adjust the fuel mix you just need to remove that silly idle limiter cap.


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## 140278 (Aug 27, 2020)

i have a 252 loncin carb in the garage and will look at the size, of the jet and bottom bolt


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## 140278 (Aug 27, 2020)

the bottom bolts thread is a 9mm x1.0 the jet thread is 8mm x 0.8 both odd balls the jet it self is a number 73 size


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## db130 (Feb 16, 2013)

Wow, a 73 jet for a 252 cc engine? That's like between a .028 and 0.029 jet. No wonder it runs lean. It could probably be drilled out to .032.


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## Pete826 (Dec 1, 2020)

I would try running 1/2 choke for like 5 minutes after you start up and let temperature warm up then turn off choke. That is what works for me. Mine runs real well doing this. I agree with they are making them to run green/lean...


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## arienskids (Jan 26, 2018)

i would buy an ebay jet and use that that way if you have to bring it in for warranty you can reinstall the oem jet


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## dcinma (Dec 13, 2017)

captchas said:


> the bottom bolts thread is a 9mm x1.0 the jet thread is 8mm x 0.8 both odd balls the jet it self is a number 73 size





captchas said:


> i have a 252 loncin carb in the garage and will look at the size, of the jet and bottom bolt


I'd appreciate it.


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## Pete826 (Dec 1, 2020)

Interesting , what size/pn would be the next size up Jet.Are you going to order one....


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## dcinma (Dec 13, 2017)

Thanks for all the information, everyone. I'm probably going to wait until the end of the season before fooling with it.


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## dcinma (Dec 13, 2017)

Check this out, seller claims it will work on the newest engines that come on Toro's. I don't know if I'm going to order one but it is interesting.








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


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## drmerdp (Feb 9, 2014)

I have a similar one sitting in a draw of my tool box. It should work on basically any Honda or clone. It Not better then jetting to the correct size, just more convenient then test and tuning through a range of jet sizes.

Im going to install mine on the 301 pred on my simplicity 860 eventually....


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## dcinma (Dec 13, 2017)

UPDATE
Finally got a chance to test it out.
Kind of hard to explain. It doesn't react to adjustment like an L head Tec. motor does. It hunts under light load, but seems to smooth out under heavy load. Instead of before when it was smooth under light load and hunting under heavy load.


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## jherbicide (Oct 14, 2021)

Sounds like the 'new' issue is a plugged or (semi plugged) idle/low speed circuit. Which is very common these days...


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## dcinma (Dec 13, 2017)

Really, that was in the back of my mind. 
Please elaborate.


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## jherbicide (Oct 14, 2021)

It hunts/searches because the governor is trying to maintain a certain rpm, but the engine can only get the proper fuel off the main/high circuit.

*First you must understand that these carburetors have two fuel circuits, (idle/low and main/high) and the amount of fuel each delivers is dependent on the throttle butterfly position, NOT RPMs. This is often a misunderstanding about carburetors*

With no load:

1. as the engine starts to slow/die, the governor opens the throttle butterfly, which causes the carb to pull fuel from the main.
2. The RPMs then rise, causing the governor to close the throttle butterfly. As the the butterfly closes, the vacuum to pull fuel shifts back from the main circuit to the low/idle.
3. But, since it’s clogged and can’t deliver the proper fuel the RPMs drop too much, causing the governor to open and we go back to step 1 and the cycle continues.

Now, once there is a load on the engine, the throttle needs to be further open to maintain that same RPM. Because it requires to be more open, the low/idle circuit is not relied upon (as much) to provide the proper amount of fuel. Hence the pugged idle/low circuit has less impact

-Idle/low speed circuits provide most of the fuel when the butterfly is relatively closed. The majority of vacuum is behind the butterfly in a closed position.










-Main/High speed circuits provide most of the fuel when the butterfly is open. In this condition the majority of the vacuum is in the venturi, where the main jet is located.










Those pics are from an aviation website, but the basic principles apply to every carburetor.






Engine Fuel and Fuel Metering Systems







www.flight-mechanic.com


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## RickCoMatic (Dec 29, 2020)

Having a decent spare carb to experiment with will save your bacon and keep your warranty intact.


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## dcinma (Dec 13, 2017)

Thanks for that jherbacide.
Ricomatic, I was thinking the same thing.


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## Richard Radford (12 mo ago)

I own a Colman mini bike with a brand new Toro 252cc electric start off of a snow thrower and it has a 22 mm mikuni carb with a 125 jet but Im thinking I need to go bigger.


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## asavage (Dec 20, 2021)

I don't know this engine, but typically a carb jetted for proper operation in cold weather will run rich when run in 40-60°F warmer conditions.


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## dcinma (Dec 13, 2017)

Ended up getting an oem replacement carburetor. Replaced the emulsion tube and jet with the high performance kit for predator engines on ebay, same thing with the pilot jet. Should have noted the sizes. Bought a carburetor pin gauge set to compare oem and aftermarket sizes. Didn't take notes.
Then the big storm hit eastern mass late February.
Well I have to say I was impressed the motor is an animal. Won't bog down or hunt no matter how hard you load it up
The jet I used is 36 it came with a choice of 35, 36 and37. Don't remember the pilot jet but it was a few sizes bigger.
Funny thing now is it runs funny in warm weather. On a 60 degree day I went to put it in the shed and it was surging, probably running to rich.
Along with the pin gauge set I got a micro hand drill bit set two carb rebuild kits. 
I don't know, seems like the old Tec L heads with the Walbro (I think) were less temperamental to temperature changes.


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