044#1 - I Have Questions

[MustangMike]

Well, after owning it since new (for over 22 years) I pulled the cylinder on 044#1 for the first time ever, felt like I was opening a time capsule. 044#1 is SN 126234303 and I purchased it new on 12/27/92. It is a red lever 10 mm saw, with a B cylinder.

I would appreciate the more knowledgeable members answering a few questions for me.

1) The base gasket is not metal, and seems to be 25/1000 thick (the new gasket is 18/1000 metal). Was the old gasket compressed, or are they different thicknesses?

2) I'm trying to determine what may have been causing an air leak, and the rubber & seals all looked good (even though I am replacing them), do the old base gaskets ever go bad & leak. All the bolts were tight, but the gasket did not come off in one piece, and did not seem "dry".

3) The new OEM piston is not the same as the one in my saw. The diameter on both is 1.965, but the original piston is a little taller (1.562 instead of 1.553), and has wings on the skirts (see pic). The original piston has just a tiny amount of wear, a bit shinny for 1/8" on the bottom of the intake side. I don't know how much difference the wings and piston height make, but I'm inclined to re use the original piston, the saw runs very clean & strong.

The squish before I took it apart was 36/1000.

I welcome an constructive/informative comments.

Thanks,
MustangMike

 

[Canadian farm boy]

So the new piston has .009 shorter skirts and no "wings". That tells me it's probably lighter and should help spool faster.
The original piston with wings I believe would possibly be more stable in the bore. How much?, I'm not sure.

I would be checking the squish with both pistons and also be checking the distance to free porting on the exhaust.
I'd run which ever piston I felt the most comfortable with. I'd also try and tighten the squish to somewhere around .018-.020.
I'd also run the new rings on whichever piston you choose. Maybe run some scotch brite around inside the jug to remove any glazing

 

[MustangMike]

I just checked squish with the orig piston and no gasket. I guess this solder stuff is not exact, or the gasket was compressed.

The first measurements (with the gasket) were with electrical solder that started at .050 (showed .036).

W/O the gasket, I used electrical solder that started at .040, it went to .023, so I think I'm good. I hear you want to be a little over, cause the actual # is a bit smaller.

 

[Canadian farm boy]

That's what I've heard before too. I would estimate that if your solder is measuring .023 your probably closer to .020-.021. Perfect IMO
How does the squish measure with the new piston?

 

[MustangMike]

I think I'm gonna leave it in the box. I don't like that the skirt is shorter.

 

[Canadian farm boy]

I'd be curious what the difference is in the weight of the pistons. Is there much difference in the piston windows?

 

[MustangMike]

They look similar.

 

[drf256]

I like short skirts, but not on Pistons. I'm pretty sure that meteors have the wings. The shorter skirt could cause a Freeport when you drop the jug (doubtful without machine work). Is it the crown to skirt you are measuring, or the bottom of the pin boss to the skirt?

You have Some valid questions Mike.

You say air leak, I didn't catch what happened. Did it start to lean out and you ship it it immediately before it did damage?

You have to check everything Mike. The impulse line can have a small crack. If it passes a vac test, the fuel supply may have an issue. Did you change the line and filter?

 

[MustangMike]

Symptoms: 1) Hard to start (like over 15 pulls), and 2) idles great for 30 seconds, then want to die, especially if you hit the trigger. Other than that, it ran just great!

So I figured something was starting to leak.

I'm installing a new boot, impulse line & seals. Was also gonna replace the piston, but I think I'll leave the original.

 

[Canadian farm boy]

Good stuff Mike. I think I would likely do the same thing your doing. New rings, scotch brite the jug, base gasket delete. Before trying to start the saw I would give it a very thorough vac and pressure test. Go over the fuel line, impulse line and intake tube closely. For the price of them is be tempted to just replace them anyway. Maybe throw a carb kit in it just to be safe. You need to find the source of your lean condition.

 

[Canadian farm boy]

Fuel tank vent?

 

[MustangMike]

The different height is from the bottom of the skirt to the top of the piston.

 

[MustangMike]

The fuel line is a "green" one, installed not long ago, and the tank vent is a 440 tank handle, also not that old (more problems I think with the orig 044 vents).

Carb was also rebuilt not too long ago.

 

[Canadian farm boy]

Fuel filter? They're cheap. At this point I'd change it just for piece of mind.

 

[drf256]

You change the spark plug?

That's my first step, always now.

 

[angelo c]

Mike, fully well knowing you've owned and operated that saw since day one. I would still go about diagnosis through a routine, consistent method. Whatever that order is is up to you but me, I go :

Clean the freekin thing because every SOB that ever gives me a saw to work on refuses to clean it. Ever
Remove muffler- visually inspect for scoring (and excessive 'play' or movement)
Block it off
Remove carby-look for scoring on piston. Put it back on or block off for pressure/vac test.
Replace decomp button w plug
Locate or confirm leak/no leak. (Replace decomp plug- almost everyone leaks)
Compressin test
Spark test - through plug and without plug
I'll do that before I ever take a cyl off. I find a systematic approach makes things faster.
Then I will pressure test every hose/ line /barb/carb that was connected to the cyl.
I'll go back and recheck everything again as I put it back together again too.

My point is check everything no matter when you replaced it everytime just like ya never replaced it.
hth?

 

[MustangMike]

New plug & fuel filter, I always do the simple stuff first.

I don't have a vac tester, but hopefully with everything replaced, she will be good to go.

Was hoping for more comments on the piston, but I will likely have it running before I get them.

Angelo, had the cylinder off, it looks great, and the saw runs very clean. Absolutely no scoring of any kind.

Maybe after 22 years, the impulse hose just did not fit tight, who knows, or it could have been the seals, you may not see the problem with them.

 

[Brian Simonseth]

The fuel line is a "green" one, installed not long ago, and the tank vent is a 440 tank handle, also not that old (more problems I think with the orig 044 vents).

Carb was also rebuilt not too long ago.

 

[MustangMike]

I feel relieved, the hard stuff is done.

Yesterday I did the seals, and today the impulse line, boot, and deleted the gasket!

Thank you everyone for all the advice. That modified screw driver worked great for removing the seals, and the T Handle 27 Torx, and the ring compressor (both are available through HLSupply) were life savers.

It is tricky (for me anyway) to get the cylinder on the piston w/o letting the piston hit the sealer. With the cylinder off, the new impulse line was easy, but then I debated what to do next. I installed the boot on the jug, then put the sealer on the base, I rotated the crank just past TDC, then inserted a screw driver in the flywheel to block rotation so when I put the jug over the piston I would not force it down into the sealer. After the jug was tightened down, I coaxed the other end of the boot through the tank handle.

It is probably a lot easier to do with 2 people, but I did not have that option.

So I will give the sealer till tomorrow to dry, and the rest of the stuff is just routine bolt on, nothing I have not done dozens of times. It is a big weight off of my shoulders, and I can't wait to fire it up tomorrow and see how it runs. Wish I had some wood to cut close by!

By removing the base gasket, I basically cut my squish in half, so I'm really looking forward to seeing how it runs.

 

[Deets066]

Either piston would be fine, if your having it ported measure skirt width, and skirt length, (from pin to bottom of skirt). If you want a long bar saw go with longer skirt, if you want a snappy shorter bar saw go with skirt width.

My 2 pennies