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372XP issues

Started by celliott, May 23, 2013, 10:45:03 AM

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celliott

I picked up a nice used 372XP on the cheap. It was formerly a small engine repair class saw, spent most of it's life being taken apart and reassembled. Because of this, I decided to go over the whole saw and  make sure all the bolts were tight, and not missing  ::) Found one bolt stripped out, that holds the oiler on and had that helicoiled. Plus the cylinder bolts were all loose  :-X  New fuel line, new fuel filter just in case, cleaned up a very small score mark on the intake side, and it's all back together.

Now the problem- I reset the carb to stock settings according to the manual, and it fired up. But, the saw won't idle for more than 5-10 seconds and then it dies. The saw doesn't want to rev up either, it sounds like it's bogging, and dies when I let off the throttle. I have fiddled with the low jet settings back and forth, and not much change. Haven't changed the High jet setting yet.

I already tore the carb apart, gave everything a soaking in carb cleaner, blew all the tiny holes out with air, reset the metering lever, and put it back together and still the same thing.

Any ideas?
Maybe a faulty rubber part in the carb? Or I didn't reassemble it right?

On a positive note, I got a free husky 345, saw has barely been used. All that one needed was a new fuel line  8) now it runs good!
Chris Elliott

Clark 666C cable skidder
Husqvarna and Jonsered pro saws
265rx clearing saw
Professional maple tubing installer and maple sugaring worker, part time logger

mad murdock

Did you put a new carb kit in it?  If not I woiuld start there, even if the saw had littile use, if it sat for years after being exposed to gas, the rubber parts coul have dried and hardened, the kit is only 10-15 bucks, and well worth the investment, that way you know for sure that things are on the up and up.  Double check the lwo pressure hose to the carb, and the fuel filter/fuel line to the carb, to ensure there are no cracks kinks, clogs or leaks.  Should start, run, and be able to adjust to your likeing after that.
Turbosawmill M6 (now M8) Warrior Ultra liteweight, Granberg Alaskan III, lots of saws-gas powered and human powered :D

bill m

Sounds like the impulse hose is off or broken.
NH tc55da Metavic 4x4 trailer Stihl and Husky saws

joe_indi

I second bill m. It could be a impulse problem.Other than broken or off, blocked.
If it has a blue ignition module,that has a speed limiter, the spark could be getting shorted out earlier.
But the black ignition coil too has had its share of problems.It dies off after a couple of sparks.After a minute it fires up again but dies.
Examine the spark plug for a loose electrode

Joe

celliott

I haven't replaced any internal carb parts yet. I have been leaning towards a carb rebuild, just wanted a second opinion.
Any way to tell if the carb internals are bad by inspection?
Quote from: bill m on May 23, 2013, 12:38:07 PM
Sounds like the impulse hose is off or broken.
Impulse line is on, I checked it over before I put the cylinder back on and it didn't appear to have any cracks or tears in it. But maybe a small one? I'll look again.
It does have the black ignition module, and I did re-gap it. I'll try another plug too, but I really think it's a fuel issue.
I tried again today, and it's definitely flooding out.
Chris Elliott

Clark 666C cable skidder
Husqvarna and Jonsered pro saws
265rx clearing saw
Professional maple tubing installer and maple sugaring worker, part time logger

AdkStihl

Quote from: celliott on May 23, 2013, 12:49:36 PM
I haven't replaced any internal carb parts yet. I have been leaning towards a carb rebuild, just wanted a second opinion.
Any way to tell if the carb internals are bad by inspection?

Easiest thing to do is to rebuild it.
Don't mess around.
J.Miller Photography

JohnG28

You can try turning the L side in about 1/4 to 1/2 turn just to try. If its flooding out at start or when revving that could be it. I would think if the carb innards are shot you wouldn't be moving much fuel.
Stihl MS361, 460 & 200T, Jonsered 490, Jonsereds 90, Husky 350 & 142, Homelite XL and Super XL

joe_indi

celliott, I will take you step by step through how to check if the impulse is working(pumping up fuel)
1.Spark plug out.Switch off. Metering chamber (4 screws) open.Metering diaphragm out.Metering lever, inlet needle out.
2.Pump cover off(Single screw).Pump diaphragm out. If strainer is blocked remove and clean.Put back everything here.
3.Connect the impulse line.Connect the fuel line(hope the pickup body is clean).
4. Open the fuel cap.Breathe into the tank and close it.Fuel might flow out of the carburetor. If that happens open the cap briefly and close it.
5.  Now pull the recoil starter. Fuel should spurt out of the carburetor in pulses after a couple of pulls.

If that happens the pump section is fine and working.
Do you have a carburetor with limiter caps or without them?
Joe

joe_indi

Its 12.57 am here and I was just getting into bed when I thought of something.
When you checked the cylinder screws, did you also lift the cylinder to have a look at the piston?
If you havent, you better do that first, because if there are any scour marks on the piston or cylinder the 372XP with its solitary ring loses compression.
Good Night.
Joe

celliott

I had to run into town today, and swung by a dealer I've never been to before to see what they thought. The man at the dealer told me I'd be wasting my time and money with a rebuild kit, and to just buy a whole new carburetor. I didn't argue with him, and didn't stay in there long  ::) I don't understand how I would need a new carburetor, the carb body itself is a block of aluminum, how could that possibly go bad?

Joe, I will check the impulse line as you described it.
I had the saw completely dissasembled apart from splitting the case. There was a small score mark on the intake side of the piston, with a small amount of aluminum on the cylinder. I used toilet bowl cleaner with hydrochloric acid in it and a 3M pad to remove the aluminum from the cylinder. The cylinder looks just fine, I can't feel any ridges or scratches on it. The piston isn't a single ring, this one does have two. Do you think the small scores on the piston would affect compression enough?Should I just get a new piston and rings anyways? I tested the compression before I found the loose cylinder bolts, and it was low, at 120PSI. I haven't retested it since I put it back together.
I appreciate everyone's help. I will get this saw figured out. Probably another trip to the chainsawr is in order soon.
Chris Elliott

Clark 666C cable skidder
Husqvarna and Jonsered pro saws
265rx clearing saw
Professional maple tubing installer and maple sugaring worker, part time logger

celliott

Forgot to add another answer to your question Joe, Yes, the carb HAD limiters. I've trimmed them off already.
Chris Elliott

Clark 666C cable skidder
Husqvarna and Jonsered pro saws
265rx clearing saw
Professional maple tubing installer and maple sugaring worker, part time logger

Al_Smith

Most dealers would prefer not to rebuild carbs .It's really a simple matter to do the job yourself  if you are so inclined .

I mean think about right now you are as old as you've ever been and you won't learn any younger .

joe_indi

celliott,
Fresh work on the cylinder or piston could lower compression, but on a temporary basis.Once the engine starts up and runs, the leaking areas get polished and compression improves.Here is what I do to achieve that extra compression to get the engine started.
Many hardliners may frown or ridicule this, but the important thing is that it works.
I have a can of grease spray that is usually intended for bike chains. I use it to spray grease onto the cylinder walls through the exhaust port, the inlet and the spark plug hole.
After this I turn the engine over for some time till the solvent in the grease has evaporated and the grease has gone into the minute crevices that  cause the leak.
If the cylinder was removed, I would prefer to rub  regular grease thinly on the piston and cylinder surfaces.
With the grease, the engine has compression to start up.Its up to you now to start up and play the throttle till the cylinder and piston seats so that an idle can be maintained.
Avoid grease on the rings.
Just check the decompression valve for any leaks.

Quote from: Al_Smith on May 23, 2013, 07:08:37 PM
Most dealers would prefer not to rebuild carbs .It's really a simple matter to do the job yourself  if you are so inclined .

I mean think about right now you are as old as you've ever been and you won't learn any younger .
100% true.
Its better to try and use a self repaired carburetor, even if not perfect, than a shop fitted new replacement.You get to learn more that way.

Joe

celliott

Quote from: Al_Smith on May 23, 2013, 07:08:37 PM
Most dealers would prefer not to rebuild carbs .It's really a simple matter to do the job yourself  if you are so inclined .

I mean think about right now you are as old as you've ever been and you won't learn any younger .
Oh, I realize that  ;)
I fully intend to do all  my own work on this saw, I was merely in town and asking advice of him. I think i'll choose not to take his advice.
I've had the carb apart 3 or 4 times now, I'm pretty sure I can rebuild it.
Went to try and do joe's impulse test, and the crankcase was full of fuel.....
So I set the metering lever a bit lower. Did joe's test, and yes it is pumping fuel.
After reseting the metering lever again, I started it, and it would idle longer, until I hit the throttle. It revs up, but dies when I release the throttle. Still think it's getting too much fuel. Gonna order a kit tomorrow.

Quote from: joe_indi on May 23, 2013, 10:02:43 PM
celliott,
Fresh work on the cylinder or piston could lower compression, but on a temporary basis.Once the engine starts up and runs, the leaking areas get polished and compression improves.Here is what I do to achieve that extra compression to get the engine started.
Many hardliners may frown or ridicule this, but the important thing is that it works.
I have a can of grease spray that is usually intended for bike chains. I use it to spray grease onto the cylinder walls through the exhaust port, the inlet and the spark plug hole.
After this I turn the engine over for some time till the solvent in the grease has evaporated and the grease has gone into the minute crevices that  cause the leak.
If the cylinder was removed, I would prefer to rub  regular grease thinly on the piston and cylinder surfaces.
With the grease, the engine has compression to start up.Its up to you now to start up and play the throttle till the cylinder and piston seats so that an idle can be maintained.
Avoid grease on the rings.
Just check the decompression valve for any leaks.

Quote from: Al_Smith on May 23, 2013, 07:08:37 PM
Most dealers would prefer not to rebuild carbs .It's really a simple matter to do the job yourself  if you are so inclined .

I mean think about right now you are as old as you've ever been and you won't learn any younger .
100% true.
Its better to try and use a self repaired carburetor, even if not perfect, than a shop fitted new replacement.You get to learn more that way.

Joe
I coated the piston and cylinder with a liberal helping of 2 stroke oil before I reassembled it.
Chris Elliott

Clark 666C cable skidder
Husqvarna and Jonsered pro saws
265rx clearing saw
Professional maple tubing installer and maple sugaring worker, part time logger

joe_indi

Its starting to look more and more like a carburetor issue, I wont say 100%.
But lets for the time being take it as a 100% and consider some home remedies.
You will need to strip the carb to its bare body for this.
Both the covers off and things like the metering lever, needle etc off, ditto, diaphragms and gaskets.
Since the limiter caps are off, remove both the L and H screws.
If you have any type of solvent available mix equal quantities of solvent, liquid dish washing soap and water together (10ml of each should do)
Use a filler or syringe or even a small tube to pour the mix down the holes of the H and L screw, the jets in the metering chamber and passages at the pump side.
Wait a couple of minutes and then use a needle spray of water to clean out the mixture.
Hopefully this will also get the jet valve working properly, which I would say is the culprit here.
Use air to dry out the car.
Reassemble using oil at the gasket seats.Metering lever level with the carb body, not below.(BTW is the metering diaphragm stiff?)
H and L 1 1/2 turn out. 
Try to start it now.
Joe

AdkStihl

Check that you have the gaskets/diaphragms in there proper order.
On the metering side (4 screw) the gasket goes against the carb body.
Just the opposite on the pump side.

Maybe also the metering lever is damaged / worn badly?
J.Miller Photography

AdkStihl

Quote from: joe_indi on May 23, 2013, 10:54:05 PM
Use air to dry out the carb.

I wouldnt recommend air pressure over 5-10psi +/-
Pressurized air will damage a fuel nozzle in a split second if not careful.

I recommend just using a good ole can of carb cleaner and use the straw to blast any dirt from the fuel circuits. I am a big fan of Berrymans B12 Chemtool !!
J.Miller Photography

joe_indi

Quote from: AdkStihl on May 23, 2013, 11:00:49 PM
Quote from: joe_indi on May 23, 2013, 10:54:05 PM
Use air to dry out the carb.

I wouldnt recommend air pressure over 5-10psi +/-
Pressurized air will damage a fuel nozzle in a split second if not careful.
--------


Thank you for bringing this up, I should have mentioned it myself. I use a regular air blower not a compressor. Air blower produces a higher volume of air at safer pressure and dries out stuff safely and faster.

And why the concoction of soap, solvent and water?
The stuff creating blockage or problems in the carb started off as resin, which was an emulsion . In its dried state soap alone will not dissolve it, similarly, solvent by itself might not dissolve it.But if you make an   emulsion of soap and solvent, most resins come off easily. By solvent I mean any hydro carbon based solvent, even a emulsion of soap and gasoline works wonders.
Emulsions made with soap and the right solvent, at times, works better than  store bought stuff .

Joe

NCFarmboy

Quote from: joe_indi on May 23, 2013, 03:30:00 PM
Its 12.57 am here and I was just getting into bed when I thought of something.
When you checked the cylinder screws, did you also lift the cylinder to have a look at the piston?
If you havent, you better do that first, because if there are any scour marks on the piston or cylinder the 372XP with its solitary ring loses compression.
Good Night.
Joe
371 50mm OEM has single ring.  372 OEM 50mm has 2 rings.  Either works in 372.  Aftermarket often uses single ring for 371 and 372.
Shep
Lots & Lots of Saws

ladylake

Quote from: AdkStihl on May 23, 2013, 10:54:59 PM
Check that you have the gaskets/diaphragms in there proper order.
On the metering side (4 screw) the gasket goes against the carb body.
Just the opposite on the pump side.

Maybe also the metering lever is damaged / worn badly?


  Yes, pay closer attention to the metering lever and diaphragms. You saw is flooding out  from stiff diaphragms , wrong order or the metering lever is too high.   Steve
Timberking B20  18000  hours +  Case75xt grapple + forks+8" snow bucket + dirt bucket   770 Oliver   Lots(too many) of chainsaws, Like the Echo saws and the Stihl and Husky     W5  Case loader   1  trailers  Wright sharpener     Suffolk  setter Volvo MCT125c skid loader

celliott

I've had the carb completely apart twice now, gave it a soaking in carb cleaner, sprayed all the tiny holes. I'll recheck the order, but I thought I got it right.
Probably won't be able to get a rebuild kit until Tuesday due to the holiday weekend, so this project will take a short break.

I do appreciate all the tips and help, thank you all.

Chris Elliott
Chris Elliott

Clark 666C cable skidder
Husqvarna and Jonsered pro saws
265rx clearing saw
Professional maple tubing installer and maple sugaring worker, part time logger

ladylake

 

If the diaphragm isn't stiff try lowering the metering lever just a bit and check for the right order, most likely you won't need a kit.    Steve
Timberking B20  18000  hours +  Case75xt grapple + forks+8" snow bucket + dirt bucket   770 Oliver   Lots(too many) of chainsaws, Like the Echo saws and the Stihl and Husky     W5  Case loader   1  trailers  Wright sharpener     Suffolk  setter Volvo MCT125c skid loader

Al_Smith

On this carb biz just to show you how easy it is .It's now 4:37EDT .I got home at 20 til 4.Got out two saws from my bench,Stihl 024 and 2.2 cubic inch Poulan .Blew the dust off rebuilt two carbs ,tested them in the wood ,cracked  a beer and here I am . 8)

celliott

It's nice living a half hour away from the chainsawr (sponsor) shop. Drove up to get a rebuild kit today. Good day to stay in and work on chainsaws, it's blowing wind and raining\borderline snowing outside here. Nasty weather.
Threw the rebuild kit in, lo and behold, it worked!  8) surprise surprise, right?
Got it tuned up how I want, now I want to test it out in some wood  ;D
The saw came with a 20" bar, 3\8 chain. Don't know why, but it has semi skip chain on it at the moment. Also has an 8 tooth driver. Think the 372 will do ok with an 8 tooth on a 20" bar?

Quote from: Al_Smith on May 24, 2013, 04:40:48 PM
On this carb biz just to show you how easy it is .It's now 4:37EDT .I got home at 20 til 4.Got out two saws from my bench,Stihl 024 and 2.2 cubic inch Poulan .Blew the dust off rebuilt two carbs ,tested them in the wood ,cracked  a beer and here I am . 8)
Oh, they aren't hard at all, I do realize that. This walbro HD was pretty easy i'd say. I can have the carb off and totally broken down on that 372 in about 5 minutes now, i've practiced enough  ::)
Chris Elliott

Clark 666C cable skidder
Husqvarna and Jonsered pro saws
265rx clearing saw
Professional maple tubing installer and maple sugaring worker, part time logger

AdkStihl

Quote from: celliott on May 25, 2013, 03:02:51 PMThink the 372 will do ok with an 8 tooth on a 20" bar?

Oh hell yeah!!
Thats how I've got one of my 044's set up.
J.Miller Photography

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