HELP. 3120xp Won't start when hot.

[drf256]

Part of the issue is saw design. Neither my 395 nor 066 ever had the same issue.

Gotta get as much heat out of the saw as possible, hence the big muffler mod suggestions.

Let the saw idle for a bit in the shade before you shut it off to refill. Even a few piss rev blips so that more air can flow through the saw unloaded.

You really don’t want to go numerically over 32:1 with milling. The saw needs to extra oil to survive. I’ve even milled using 16:1 without issues. Fuel with a higher boil temp may help you, but milling out of the sun/cooler times of the day/muff mod/rest period before shutting to refuel should help the most IMHO.

The carb is overly fat from the factory. Adding a H circuit to lean it out will actually make your problem worse than it already is.

 

[huskyhank]

The part about letting the saw sit idling cool off along with a few revs for a short period of time is not a bad idea at all. Same for choice of fuel, especially if you have crappy gas where you live. I’ve had stock and modded 3120s and never had any trouble from them. They seem to be pretty much appliances like a refrigerator - they just sit there and work.

Ultimately, I’d plan on getting the saw worked over. The difference between a stock 3120 and a modded one is about the same as the jump from a 100cc saw to a 120cc saw. Its a whole ‘nuther thing and worth the money.

Included in that I’d do the carb high screw for tuning. I've had ‘em both ways and the fully modded saw is just better. I also think 40:1 is plenty of oil.

On the other hand you have gotten different advice from people who know more about this than I do, by a long shot. What I relate is just my personal experience.

 

[huskihl]

Part of the issue is saw design. Neither my 395 nor 066 ever had the same issue.

Gotta get as much heat out of the saw as possible, hence the big muffler mod suggestions.

Let the saw idle for a bit in the shade before you shut it off to refill. Even a few piss rev blips so that more air can flow through the saw unloaded.

You really don’t want to go numerically over 32:1 with milling. The saw needs to extra oil to survive. I’ve even milled using 16:1 without issues. Fuel with a higher boil temp may help you, but milling out of the sun/cooler times of the day/muff mod/rest period before shutting to refuel should help the most IMHO.

The carb is overly fat from the factory. Adding a H circuit to lean it out will actually make your problem worse than it already is.

The normal H circuit mod only adds fuel for use with the unlimited coil. But the aux high speed jet can be filled and drilled smaller, and along with the additional H jet circuit could be of some use.

 

[huskihl]

The difference between a stock 3120 and a modded one is about the same as the jump from a 100cc saw to a 120cc saw

Quite a bit more than that even. Using 36” .404, cut times go from 1 minute stock to 25 seconds ported with unlimited coil and adjustable carb

 

[deye223]

Quite a bit more than that even. Using 36” .404, cut times go from 1 minute stock to 25 seconds ported with unlimited coil and adjustable carb

So is this in a 32" log or a smaller one

 

[huskihl]

So is this in a 32" log or a smaller one

34-36” sugar maple crotch. Not soft wood by any means. Even by your standards

 

[davidwyby]

Sweet! Now I have a target time!

 

[drf256]

Interesting Tidbit I found on AS posted by @Lone Wolf

https://www.popularmechanics.com/ca...blend-gasoline-whats-the-difference-13747431/

May be contributing. Unclear if E-free does the same.

 

[US Navy Vet]

Just an update. I ran the VP pre-mix and still had the issue but not nearly as bad. I picked up so skip tooth chain rather than full comp to work the saw less. I picked up some race fuel from our local track and will run that. I picked up a used muffler and poked a hole in it on the flywheel side. Everything seems to be working fine.

Thank you all for the advice and getting me back going. Hopefully I won't run into too many more logs that I have to slab up to fit on the sawmill.

 

[US Navy Vet]

One last question... The racetrack near me carries sunoco race fuel. I can buy 260 GTX unleaded or leaded. The leaded fuel is much cheaper in the 5 gallon cans. Would running a leaded fuel be better for the saw since it does provide extra lube for cooling or would it be detrimental to the engine? Thanks again.

 

[davidwyby]

I tried some VP110 milling. I wouldn’t buy too much until you try it.
Fuel stabilizer might help.

 

[US Navy Vet]

I tried some VP110 milling. I wouldn’t buy too much until you try it.
Fuel stabilizer might help.

I just read up on the thread where you showed pictures of using the VP110. I guess I'll have to rethink how I go about this. The pump gas near me is all crap and I don't like running it in any of my equipment.

It's not a storage issue with my fuel. I burn about 5 gallons a month while milling lumber and everything is emptied out when it sits longer than a week. I just dump the 2 cycle in the car and keep it lubed up.