dissecting an earthquake chainsaw

[jteam]

It was clean used vegetable oil.


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[Chris-PA]

It was clean used vegetable oil.

Well, I am no expert but canola oil is produced from rape seed, and may well have different characteristics from others. Also, it is possible likely that heating changes the characteristics. Some bio-oils have pretty impressive properties, such as castor oil.

 

[jteam]

Yeh, I wondered if the oil being used previously had any effect on its properties. It lubed great while running, but a little thin. Smelled like French fries when the bar warmed up good,


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[deputyrpa]

I had to do it! So....I picked up a 3814 on eBay for $37 to my door. It was lightly used, with a small nick on the bar, but no wear. I fueled it up and ran it through an 18" fresh-cut red oak log. It bogged when leaned on and it also seemed that the clutch was slipping when I loaded it. So, I went directly to the basement and disassembled the plastic, and decided to first do a muffler mod. I looked at some of the jobs previously posted, and decided to do it the a differently. I know how pics are loved, so here's the story:
First, I used my ox-acetylene torch to heat, and used a sacrificial small screwdriver to unpeel the crimp.


I separated the housing, and then used the screwdriver to lever the baffle out.

And it's apart.

 

[deputyrpa]

That's a nasty piece of brillo there! It's gotta come out.
A Dremel and a cutting wheel

There's enough of a gap between the baffle and the brillo cage to cut the spot welds.

And it's removed.

A little more heat to stretch the baffle port.

 

[deputyrpa]

Now to attack the front side exhaust port hood scoop. I torched the spot weld on the top side and smacked them with a utility chisel.

I bent the scoop up and cut off the top side "foot".

Then I heated it and straightened its curve, and checked for clearance with the baffle.

 

[deputyrpa]

Now for the front side exhaust ports.
The Dremel, with the cut-off wheel worn down to size, is perfect to cut two more slits 5/16ths of an inch apart.

Almost perfect.

More heat and the sacrificial screwdriver was used to open them at the appropriate matching angle.

 

[deputyrpa]

Now for reassembly. Some cherry-red heat and a small knocking hammer

Finished off with a squeeze in the vise

And it's done!

How did I do?

 

[jteam]

Nice work Deputy, I did my front ports similar and preferred the stock like appearance. I like the idea if opening the crimp, too bad my porta torch tanks were empty . I coulda saved a ton of stitch welding doing it your way.


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[Chris-PA]

I've noticed a strange characteristic of my CS3816, in that is seems to take a really long time to warm up before it will really run properly. Prior to that it's a dog, doesn’t want to rev and acts like it's too rich. So I decided to take a look at the ignition module. I noticed it is very similar to the GZ4000/GZ400/Ryobi 10532 design, but just a little different:

So I swapped one in. It didn't start at all. Popped a couple of times and tried to remove my fingers, but that's it. So I looked at the flywheels, and sure enough they are keyed quite differently:

I have no idea what the advance curve looks like, but it works great in the larger saws, so why not! I put it in and it started right up.

And behaved exactly like it always did! LOL.

 

[Chris-PA]

Next I pulled the carb off and cleaned it up. I removed the choke plate and used a small file to remove the casting ridge in the venturi, and lowered the metering arm a little bit. That did help some. In truth I think I raised the exhaust a bit more than I should have, and I really should make a mandrel and cut the bottom of the jug. But really, it works OK and no matter what I do it will still get spanked by its larger strato brothers, so I'll probably leave it alone.



It's not really quite as bad as it seems there. That is a hard 15" white ash crotch, which is a bit too much for it. I will probably be removing the 17" bar and putting a 16" back on.

 

[deputyrpa]

That saw is honking right along! Not bad. I like the way my 38 pulls the 14" bar.

You mentioned raising the exhaust. I assume you ported it? By how much. I want to try my hand at it, but I have only a tidbit of knowledge on how to do it correctly.

 

[Chris-PA]

That saw is honking right along! Not bad. I like the way my 38 pulls the 14" bar.

You mentioned raising the exhaust. I assume you ported it? By how much. I want to try my hand at it, but I have only a tidbit of knowledge on how to do it correctly.

A 14" might be just right, but I don't have any. I have several of those "Tiger" branded 16" bars with 9-tooth tip sprockets from Baileys, which I think it what will go on it.

The port durations were:
Exhaust = 151
Intake = 157
Transfer = 110

The squish is 0.030" after removal of the base gasket. The exhaust is not really raised that far, but you need to conserve all the compression you can.

Here you can just see the remains of the ridge in the top of the exhaust port:



It really is a very nice saw to use, it's just that I have several of the strato 40cc GZ4000-based saws which are the same chassis with a lot more power.

Oh, and that was TriLink safety chain. Very sharp, and it is the newer type with smaller radius cutters, but still.

 

[Steve NW WI]

I tried out my 4518 today for the first time. Bone stock - just sharpened the trashed safety chain it came with, otherwise straight out of the box.

- It was a little rich, but not bad. I'd leave it there at least for a few tanks for breakin.

- Doggy, remember no mods whatsoever yet. I'm sure a MM will help, also getting the rings seated, etc. will gain some.
- Clutch sucks. It stalls with the least bit of pressure applied. Unless there's an easy cheap fix, this is gonna keep me from bothering with it any more. I'll just put it on the shelf till someone needs a loaner saw.

It did pop on the 2nd pull from prime, and was up and running on the 4th pull.

 

[MasterMech]

- Clutch sucks. It stalls with the least bit of pressure applied. Unless there's an easy cheap fix, this is gonna keep me from bothering with it any more. I'll just put it on the shelf till someone needs a loaner saw.

It ain't the clutch. The motor really is that anemic. Fix the power issue and the clutch problem disappears.

You should see the exhaust port, shamefully small for a 45 cc.

 

[Chris-PA]

I tried out my 4518 today for the first time. Bone stock - just sharpened the trashed safety chain it came with, otherwise straight out of the box.

- It was a little rich, but not bad. I'd leave it there at least for a few tanks for breakin.

- Doggy, remember no mods whatsoever yet. I'm sure a MM will help, also getting the rings seated, etc. will gain some.
- Clutch sucks. It stalls with the least bit of pressure applied. Unless there's an easy cheap fix, this is gonna keep me from bothering with it any more. I'll just put it on the shelf till someone needs a loaner saw.

It did pop on the 2nd pull from prime, and was up and running on the 4th pull.

It's the same clutch as on all the RedMax GZ4000 varients, of which I have several and have never had one slip. So if it is slipping take a look at it as there must be something amiss, it's not an inherent problem in the design. It is a 3-shoe clutch.

It's probably the saw bogging - it is amazingly choked up stock.

 

[deputyrpa]

It's the same clutch as on all the RedMax GZ4000 varients, of which I have several and have never had one slip. So if it is slipping take a look at it as there must be something amiss, it's not an inherent problem in the design. It is a 3-shoe clutch.

It's probably the saw bogging - it is amazingly choked up stock.

Take a look at my MM post on page 153 to see what the 38cc muffler looks like inside. The cat was so dense I had a hard time blowing though it. It runs so much better with the muffler opened up I may not even port it. I took the rakers down several swipes to get some more bite, and it really spits some chips now. It'll be my tractor and excavator saw for sure....I don't want to run over my 335XPT again!

 

[deputyrpa]

very nice mod. I will give it a try on my next one. I did my first one fast and easy, just by-past the cat and left it in place. Yours looks much nicer.

BTW - I'm good friends with WSJchester on this site, who I think you sold an Earthquake to last year. Despite a long hiatus from this site, I remember your wife was about to have hip surgery. I hope it turned out well.

 

[Steve NW WI]

I'll give the muff mod a shot. It's got it's hands full to impress me though, in a 14" chunk of red oak, my de-catted but otherwise stock 420 Dolmar was well under half the time it took the 'Quake to bog its way through it.

 

[MasterMech]

I'll give the muff mod a shot. It's got it's hands full to impress me though, in a 14" chunk of red oak, my de-catted but otherwise stock 420 Dolmar was well under half the time it took the 'Quake to bog its way through it.

The difference between my stock 4518 and the one I ported was amazing. The muff modded and ported quake was faster than a 025 in 12" black locust and the quake was pulling PM chain. (RS on the 025)