Diagnosing the Farmmac F372, problems from day 1

[@IndianaDoug]

Just getting around to watching this. Good job finding the issue, I knew there was something wasn’t right straight out of the box. That intake boot smh🤦🏻‍♂️

[@pa4765]

Another TH-camr took it apart and noticed that the ports had rough leading edges. Maybe the piston shaved off the edges and the metal shavings were inside the piston.

[@oakiewoodsman]

I have been waiting for this video to come out. Interesting stuff

[@FiddleMaker63]

lol. You know it is foreshadowing when the new saw comes with tools to replace the cylinder. 😂 The finest tofu dredge. All these saws should come with mechanics special disclaimer on the box. It is fine if you expect this going in.

[@diggindiggenit6540]

Wow a population near one billion and a half, you would think they could hire One person for quality control

[@merdith6]

My guess is I mean aside from the boot and the carburetor and all the other crap it looks to me like maybe the grooves where the piston rings go are cut too deep so it's not keeping the piston rings far enough out to keep the Piston away from the walls of the cylinder or the piston rings are not wide enough

[@novicelumberjack]

Had to go through a lot with the Farm-Hack. Runs damn good now. I got 3rd place with it at clone wars.
th-cam.com/video/g7kz81HQ5LY/w-d-xo.htmlsi=duAOyFDM18DYuKm_

[@crxess]

Problem was not Lean, it was Fuel Diversion.
We could debate running out of fuel vs. running lean for a while. I am of the opinion, when the Fuel starts to run out the Saw Runs lean, the Saw rpm takes off, Revs way up.
However, perhaps the crack was enough to suck Dust(fine dirt) into the top of the cylinder causing abrasion damage.
My Clone saw, a no name 373xp clone, had the same Boot Fold when it arrived. Fortunately I caught it while doing a once over before I ever started the Saw.
I couldn't get over the Filter leaning right when I pulled the cover to check the wing-nut tightness.
After removing the filter I pulled the main cover and found - (1) the Boot looked Twisted, (2) the Motor side was folded and out of the lower frame, (3) the Clamp was non-functional and the adjuster was free walking along the serrations.
It took some work to get the Grommet to sit properly and the Carburetor level. The clamp was an easy repair.
I only put a little less than 1/3 tank of fuel in to do the initial run-in, (3) heat cycles....... and was Surprised by the saw suddenly doing a Run-a-Way during the 3rd cycle. RPM rapidly rose to about 10k before my brain yelled SHUT IT OF DUMBY!!!
I did and almost immediately realized it has probably run out of gas. Yep, dry tank.
I added gas and have run it a few more times, but no cutting yet. Just waiting for my - Idiot Switch - to come in ad it arrived yesterday. Idiot Switch = Momentary switch for Dummies that keep forgetting to turn the saw on - lol.
*Back to my original lean argument - Running out of fuel = Not enough supply and To much oxygen which is the definition of Lean.(in my humble opinion)

[@wayneanderson991]

Ring gap may have been to tight and scored cylinder thus the piston roughness all the way around the piston. I have seen this on the 372 clones.

[@joec9680]

I think you nailed it.

[@VintageSaws]

#1 cause of blown top end on any 2 stroke is ripped intake boot. Causing it to run lean. It is weird how it seemed rich in the videos even with 2 different problems that would cause it to run lean.

[@patthesoundguy]

I think that the piston to bore clearance is completely wrong. The top of the piston definitely looks like it was too tight in the bore. I agree, there is no real sign of any heat damage there. I bet if you can dig up another piston, and it fits in the bore right, you will be golden.

[@CutterCH]

Although it looks kind of like it ran lean, it didn't. It looks exactly like the piston is too large for the cylinder. And coming from a clone saw company, it's 100% possible. Seen this before on clone saws. Ripped intake boots, rough intake, exhaust, and ports that are so jagged it'll kill a piston in no time. Straight out of the factory. I'd measure that piston vs OEM piston. Also measure that cylinder vs OEM. I'll bet you anything there's going to be some discrepancies.

[@merdith6]

I agree

[@aaronpowell4885]

No clue if it's true or not but I've heard that some 2t engines from overseas are test run, for a very short time with some type of gas like propane or natural gas😬 that teardown makes me wonder.

[@rogercrouse5531]

Are you using Tygon Fuel line as Impulse Line ????

[@MrJeepfreak1972]

How does the port chamfering look?

[@garrytalley8009]

No doubt you got one of the bad ones. Best bet would most likely replace the cylinder and piston with maybe a Hyway. Pretty good quality for the money and go from there after replacing your line and rubber boot. If you are going to run it in competition there is no sense wasting time on just throwing another piston in and see how it works. It's a waste of real time. But because one gets a bad apple every once in a while, it doesn't mean you have to quit eating apples does it? When you sometimes run your factories with slave labor things happen.

[@Dan_Akins]

On a positive note, looks like the bottom end has oil sheen. What kind of oil and ratio do you prefer?

[@novicelumberjack]

Red Armor 40:1

[@lifebehindtheaxe3835]

Where can I get your shirt at? I'd wear it at my comps

[@ladislavgazdik7595]

It was too lean that it was four stroking. It has enough fuel for only every second ignition.

[@Doc-Cole_Trickle-of-Chainsaws]

👍🆙BigGuy

[@Doc-Cole_Trickle-of-Chainsaws]

Also some have mentioned the Neotec muffler's paint flaking off from inside and getting back into the cylinder. Don't know if this was a factor here

[@aaronpowell4885]

I had almost forgotten hearing that! I think it was a neotec that Chickanic had in her shop that happened to.

[@jjm3254]

👍

[@ToddAdams1234]

You can tell by looking at the top of your piston that it’s a little lean. That piston is TOO clean.
BTW, an RPM limited coil “could” cause you to run it more & more lean trying do what happened IN ADDITION TO the intake boot being tore. BUT, that’s still no reason for not finding yourself one of those black RPM unlimited coils for the 372.

[@alexstromberg7696]

You've never ran alky fuel. Almost no build up.

[@Marty1959]

Think maybe it might be a bad carburetor

[@jackpinesavageadventures3142]

👍🏻👏

[@DanielDoneRight]

that'll do it bud

[@coolestguyontheplanet723]

Comment from me today 😊

[@JandSChainsaw]

💩 will buff out

[@crazyfeller5704]

Those pistons are so cheap, soft…bad chamfering in the cylinders. All hallmarks of import cylinders.

[@joeysweet9045]

I think myself i would just trash it or part it out if anyything is use able on it! Bad carb and boot, bad jug, and bad piston! Hell you had better take a good look at the piston rod and crank on it because they might be bad!