Little Pig needs advice from the Herd ... Idling problem after rebuild.

DiggersDad

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I picked up a PP 295 that was thought to be junk. It had about 160 psi compression and good spark. It was dirty, had an air leak and needed a fuel system rebuild. I tore it down, put in new seals and bearings, rebuild the carburetor and put in new lines and filter. I opened the exhaust port just a little (widened it just a bit and left the top and bottom alone) and gave it a muffler mod when I had it apart. I also advanced the timing about 5 or 6 degrees.

It will start and run just fine. In fact, it is pretty impressive at WOT buried in wood for a 46cc Poulan. However, it will not idle to suit me. It takes longer than normal to "wind down" to idle and I can't dial the idle in just where I want it. When I adjust the low needle it either turns the chain just a little or dies. I can't find that happy spot where it will idle all day without turning the chain. I know the seals are good 'cause I did a vacuum and pressure test when I reassembled. I've rebuilt dozens of carbs without a problem but maybe I missed something on this one.

So, before I tear into it again - what am I missing? Do I have the timing advanced too far? It really rips in the cut. Did I miss something on the carb rebuild? The high side is out almost three full turns and the low side about 2½ turns.

Anyone?

Please?

Oink?

100_1775.jpg100_1776.jpg100_1777.jpg
 

leeha

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You got an air leak somewhere.
3 turns on HI and 2.5 on LOW, That
should be running so fat. And if it's
taking it's time to come down to idle
tells me your sucking air some where.





Lee
 

Chity_Avatar

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You got an air leak somewhere.
3 turns on HI and 2.5 on LOW, That
should be running so fat. And if it's
taking it's time to come down to idle
tells me your sucking air some where.





Lee

This....I have an 028 in the same boat right now but I haven't had time to look for a leak. Stupid things like a cracked impulse fitting on the case......Pressure and vacuum test should find your issue. My 028 is almost 3 turns out on high and just about the same on the low speed and it runs and cuts good but the idle is sporadic and slow to come down.
 

DiggersDad

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You got an air leak somewhere.
3 turns on HI and 2.5 on LOW, That
should be running so fat. And if it's
taking it's time to come down to idle
tells me your sucking air some where.





Lee

I didn't know that about the low side. Looks like I'll run another vacuum and pressure test.

When I tested it after I put the seals in I ran the test with the exhaust and intake sealed off, no carburetor. What are the chances my seal between the carb and intake side of the cylinder is bad? I used the old gasket because it "looked" like it was in good shape.

Thanks!

and oink! :cool:
 

leeha

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Your leak could be anywhere.
Show us with pic's how you pressure tested it.





Lee
 

Chity_Avatar

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I didn't know that about the low side. Looks like I'll run another vacuum and pressure test.

When I tested it after I put the seals in I ran the test with the exhaust and intake sealed off, no carburetor. What are the chances my seal between the carb and intake side of the cylinder is bad? I used the old gasket because it "looked" like it was in good shape.

Thanks!

and oink! :cool:

High should be in the 1.5 turn range and the low should be a 1 turn out or there about. She be suckin air. It's not to often I find gaskets to be the problem. Seals and fuel lines are usually the culprit.
 

weimedog

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Does that saw have one of those plastic carb mounting systems with an "impulse pipe" that is sealed in the cylinder with a grommet? I had a Husqvarna 41 which is a Poulan with a similar issue. Went thru all the standard things .. and found two issues. One that plastic carb mount was pinching the fuel line in the stock position...didn't hurt the idle. And the "Impulse pipe grommet" was rotted which DID mess up the idle because at low RPM's as the carb had a realty weak pulse.
 

8433jeff

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I will agree with you folks that after a rebuild that is where a carb should be set.

But with these Poulanavarnas, I have found that its not uncommon to have a carb turned out 2.5 to 3.5 turns on both sides, especially after a muffler mod.

If its a clamshell, its possible you have a leak after running it, I am unsure whether you rechecked the pressure or vacuum. The long return to idle does sound like an air leak. Be sure the throttle linkage is free, sometimes a symptom is caused by a simple stupid thing elsewhere.

Could be the mounting plate for the carb is cracked somewhere also. Or a bad gasket there.
 

Barneyrb

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I have found on the newer Poulans that to get it to run right the carb adjustments would beso far out you'd swear it had an air leak. Here is what I've found that helps, start with clipping a couple of coils from the needle valve spring. I've clipped as many as 4 in the past because of pop off pressure.

As for the idling down issue more low jet usually fixes that.....

BTW....for making the saw run to its potential you will need an older model muffler.....that new style just don't work for me.
 

67L36Driver

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Reminds me of a Husky 340 I traded to a fellow in n. Arkansas. Adjusting that carb. had me pullin' my hair out.

Glad he likes small Huskys....................................................

The XL-925 was soooooooooooooooo much easier to deal with.
 

DiggersDad

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Does that saw have one of those plastic carb mounting systems with an "impulse pipe" that is sealed in the cylinder with a grommet? I had a Husqvarna 41 which is a Poulan with a similar issue. Went thru all the standard things .. and found two issues. One that plastic carb mount was pinching the fuel line in the stock position...didn't hurt the idle. And the "Impulse pipe grommet" was rotted which DID mess up the idle because at low RPM's as the carb had a realty weak pulse.

BTDT with the "impulse pipe". They seem to rot quickly.

I will agree with you folks that after a rebuild that is where a carb should be set.

But with these Poulanavarnas, I have found that its not uncommon to have a carb turned out 2.5 to 3.5 turns on both sides, especially after a muffler mod.

If its a clamshell, its possible you have a leak after running it, I am unsure whether you rechecked the pressure or vacuum. The long return to idle does sound like an air leak. Be sure the throttle linkage is free, sometimes a symptom is caused by a simple stupid thing elsewhere.

Could be the mounting plate for the carb is cracked somewhere also. Or a bad gasket there.

Agreed on the settings after a muffler mod. These little Poulans like to have lots of fuel once they're opened up. Having the high turned up didn't bother me. The low seemed a bit much.

Throttle linkage is free. "simple stupid thing elsewhere" is a distinct possibility.

I have found on the newer Poulans that to get it to run right the carb adjustments would beso far out you'd swear it had an air leak. Here is what I've found that helps, start with clipping a couple of coils from the needle valve spring. I've clipped as many as 4 in the past because of pop off pressure.

As for the idling down issue more low jet usually fixes that.....

BTW....for making the saw run to its potential you will need an older model muffler.....that new style just don't work for me.

Thanks for the tip on the valve spring, I hadn't thought of doing that on a modded saw but it makes sense.

As for the muffler, I'm not crazy about the new style either but I don't want to put much money in this one. I matched the inlet to the exhaust port, then uncrimped the muffler to open the baffles inside. Once they were open, I left the stock opening and then drilled 4 quarter inch holes in each of the tubes that hold the screws to the cylinder. After those tubes can let exhaust out, I drill out the cover plate to match them and put a screen under the cover. It can breathe. 100_1776.jpg

Reminds me of a Husky 340 I traded to a fellow in n. Arkansas. Adjusting that carb. had me pullin' my hair out.

Glad he likes small Huskys....................................................

The XL-925 was soooooooooooooooo much easier to deal with.

I don't remember what the idle problem was, seems like it was some junk blocking the impulse line. I'm glad that trade worked out for both of us. :cool:
 

DiggersDad

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Your leak could be anywhere.
Show us with pic's how you pressure tested it.





Lee

I'll have to take some pics when I tear it down. I remove the carb and muffler, then use a piece of innertube bolted down with an aluminum plate to make the seal. It held vacuum for about 10 minutes but anything is possible on a rebuild. Wouldn't be the first one I've messed up something.

DD
 

Eccentric

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Those saws have a throttle cable. Could be that there's an issue with it keeping the throttle from closing. Otherwise.............I'm thinking air leak. Could also be the intake boot. Poulan changed intake boot and carb mounting flange styles sometime during the production run. IIRC, Type 1 and Type 2 are one style, while Type 3 and 4 (along with the Poulan Pro 4620) are another. It's in the IPL's.
 

naked arborist

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Those saws have a throttle cable. Could be that there's an issue with it keeping the throttle from closing. Otherwise.............I'm thinking air leak. Could also be the intake boot. Poulan changed intake boot and carb mounting flange styles sometime during the production run. IIRC, Type 1 and Type 2 are one style, while Type 3 and 4 (along with the Poulan Pro 4620) are another. It's in the IPL's.

That is some spot on info there on 1-2 or 3-4 series. I think he has a hung throttle plate muhself.
 

Jimmy in NC

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I didn't know that about the low side. Looks like I'll run another vacuum and pressure test.

When I tested it after I put the seals in I ran the test with the exhaust and intake sealed off, no carburetor. What are the chances my seal between the carb and intake side of the cylinder is bad? I used the old gasket because it "looked" like it was in good shape.

Thanks!

and oink! :cool:

New gasket there is where I'd start. My 288 was acting wonky. With a new gasket there it was idling very low. Fixed an air leak that was tuned through before.....glad I found it.

Sent from my MiniMac running E-85!!
 

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