372XP rebuild for a newby

[brianpgriset]

Ok guys finally had some time to pressure test! Whipped up some block off plates from 1/8" plate and edpm rubber sheet I had around. Used my new mighty vac (cool tool) and pumped to about 11psi per husky repair book. Dropped to about 10 psi in 30 seconds which is within husky spec (.8 bar to .6 bar in 30 sec). I went ahead and did vacuum even though husky doesn't spec testing it, drew 10 inHG vacuum for 1 minute, dropped to about 9inHG in 60 seconds.

From reading around here sounds like my case is sealed up good to go unless you guys have any input. Does it sound like my saw is sealed up enough?

 

[brianpgriset]

Btw I know the gauge says 0 in the pic, just took it for demonstration!

 

[brianpgriset]

Exhaust block plate.

 

[brianpgriset]

Ok, was getting antsy to get this thing running. Rebuilt the carb, and put on the exhaust, handle, and plastics. I plan to do a muffler mod but I'm remodeling my garage and can't hook up my welders yet so it will have to wait a bit!

Anyways filled it up with some mix and oil, set carb to 1-1/4 turn out on L and H and gave it a pull. Came to life on the 6th or 7th pull. It died a few times, still need to work tuning but it runs! Also oils real good to. I didn't run it much but noticed it was wet on the exhaust port and plug so I think it's a good bit rich but that's ok.

Now I get to learn tuning. Oh and I still need to get some chain! About to order some now.

Not pretty but it should be a decent runner.

 

[psrumors]

Congrats! You should be proud. Be sure to video the first cut with your new saw.

 

[brianpgriset]

Ok the saga continues two issues/questions:

1. Vibration - lots of vibration idling and reving. The pull starter handles dances all over the place! Already rattled out an exhaust bolt but it was a bit lose. Is this normal? Does it make a difference i dont have a chain yet? Like the chain helps damps some vibration? Could the AV springs be tired? Or is it just that its an older saw and doesnt have as good AV?

2. Wet/oily exhaust - noticed some mix coming out around the muffler. The bolts were a bit lose. Im no tuning expert but i did run through the madsens procedure once to get it started. It runs well and 4 strokes good at WOT. Is the oil normal in the muffler? Its not shooting out or anything, just a good film coating the muffler inside. Could i just still be dead rich on the H screw? Im thinking I'm just rich on the H. I was careful the set the metering lever at the proper height in the carb. A tach would help a bunch with this!

 

[super3]

1. Vibration - lots of vibration idling and reving. The pull starter handles dances all over the place! Already rattled out an exhaust bolt but it was a bit lose. Is this normal? Does it make a difference i dont have a chain yet? Like the chain helps damps some vibration? Could the AV springs be tired? Or is it just that its an older saw and doesnt have as good AV?

I don't think you have the crank centered. This should have been done before the seals are installed to get a good feel of nice and free. (no seal drag)
Anyway, now.........
Use a brass punch and give it a rap on the end of the crank on the flywheel side,(no need to remove flywheel). See if that smooths it out.

 

[Chris_In_VT]

Yeah, you can't accurately tune it without a chain on. IMO you should tune it in the wood. Probably just pig rich right now, if it's 4 stroking without a chain on it.
As for the vibrations, it's a modern saw with pretty good AV. Don't think it should be rattling like that. If all 3 AV springs are connected and not broke, I don't know why it would be vibrating so badly...

 

[brianpgriset]

I don't think you have the crank centered. This should have been done before the seals are installed to get a good feel of nice and free. (no seal drag)
Anyway, now.........
Use a brass punch and give it a rap on the end of the crank on the flywheel side,(no need to remove flywheel). See if that smooths it out.

I did center it, used a brass drift. It had a bad drag after I first put the halves together. It took awhile but after a few good whacks it loosened up significantly so I don't think that's it.

I'll double check the AV springs.

Honestly it might be nothing and I'm just in my typical project paranoia where I'm hyper sensitive to anything remotely not as I expected.

At this point it's going to sit until I get my chain in.

 

[super3]

I did center it, used a brass drift. It had a bad drag after I first put the halves together. It took awhile but after a few good whacks it loosened up significantly so I don't think that's it.

Are both ends running true, no run out?

 

[brianpgriset]

I honestly didn't check for runout on the crank ends. The crank didn't look bad when I had it out. After I got it centered it ran very smooth no binding.

After I get the chain in ill take a video and you guys can tell me if it's truly excessive or not. I might just be overreacting.

Could it have a bent crank? I'd think for sure I'd notice or the saw would be dead already....

 

[brianpgriset]

The other thing I might do is swap out the aftermarket clutch I bought for the OEM I have still. Incase it's out of balance.

 

[brianpgriset]

Watch this video:



My saw appears to have almost the same vibration. Note dancing pull starter handle at high revs and bouncing choke handle. I'm thinking I'm just paranoid...

Time wil tell.

 

[MechanicMatt]

Brian, I've never actually looked at the pull start handle while reving my saws up, usually cutting wood. Did you use a bit of oil to pre-lube the cylinder walls? Could that be your excess oil in your muffler? Where do you have the screws set for base tune?

 

[brianpgriset]

Back from the dead. It's up and running. I found excessive vibration was being caused by carb flopping around as the little black rubber mounting piece was broken in half. Got a new one of those. Also got it tuned in a bit better and will start 3-5 pulls. Acceleration is snappy. 4 strokes a bit it wot but probably needs refinement on the tune since I don't know what I'm doing.

Last question. I put it in some wood this last weekend, just a few pulls. Feels like it might be a hair underpowered but I'm not sure how a saw this size is supposed to run.

I checked compression and got ~165psi hot. That seem right for a 372xp with base gasket delete? I still haven't done the muffler mod. Do I need the muffler mod to get the saw to wake up from the increase in compression?

I was using full comp Oregon LPX chain on a 20" bar on dry tallow wood for the short runs I did. Not sure if that changes things.

Looking forward to getting some more time on it though! I can't wait to muffler mod!


Almost forget to ask, I ended up using a Champion plug for this, is this ok? I have it gapped to 0.020". I think I saw most recommend NGK