Jred 2159/359 Zama bogging

bkj110

bkj110

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Hi all, long time listener, first time poster. I have a 2010 Jred 2159/Husky 359 I bought new that has never transitioned off idle to load/throttle cleanly. Always have had to feather it. Saw is stock, carb is stock Zama C3, saw came with the metal intake boot clamp. It's got to the point where I can hardly get it to rev up off of idle let alone put any load on it. So I take the carb apart, diaphragms look good, no dirt present internally, blow it out, put it back together, fuel & vent lines hold pressure when I blow in them, same issue. Flip on its side, loosen fuel cap, same problem, so I don't believe it's a vacuum problem. I've ran VP C9 (95 octane no ethanol) and Blendzall green label for the saw's life, and prior to knowing it's going to sit for a while, I dump the fuel and let it idle itself dry. FWIW, compression is good & the piston skirts are clean/no signs of a leak & dirt entering. I've been rebuilding two strokes & carburetors & tuning/racing them for 25 years but no experience with the Zama Chinese junk. But I can't find a rebuild kit for this carb either (probably because they're $50 new?). I have it rather rich at idle in an attempt to get some fuel in for it to transition to WOT. If I clean up the idle, it just bogs & stalls as soon as you hit the throttle. High circuit is full rich to the stop & it just zings once it does pick up, put too much load on it and it bogs, too lean.

Any tips/pointers? If it's just toss the carb, are the Walbros "fixed" or do they still need attention? I don't want to buy more Chinese garbage.


Thanks!
 
bkj110

bkj110

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Also, compared to my 15 year old 2171, it's night & day on the throttle response & acceleration, and that thing's never been rebuilt.
 
DND 9000

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If it is a C3-EL42 carburetor, you would need the RB-163 rebuilt kit.
 
Bob Hedgecutter

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That Zama Chinese junk carb is actually the better of the two offerings for this model of saw- the Walbro was known to give problems.
NEVER transitioned- so you did not buy it new from a dealer? It came to you with this problem?
Proper cleaning (no high pressure compressed air!), proper full kit, correct assembly, mixture screws set to factory spec (both 1 full turn out from lightly seated should get you started).
Check manifold and the small impulse line for cracks- ideally pressure and vac test the powerhead.
Remove the chain, bar, clutch and oiler and run the saw- any different?

Rather rich at idle is probably not a great bet- adjust the L screw to give max revs at idle and then turn it out 1/8 to 1/4 so it is a little rich- but not rather rich. Rather rich on L might be causing fuel pooling and flooding as it transitions from the L circuit to the H.
The coil starting to peter out can also first show as some erratic tuning type issues.

This family is pretty simple and easy to work on, running well they are a great near 60cc saw and you got a Red one- they are always better! :p
 
bkj110

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If it is a C3-EL42 carburetor, you would need the RB-163 rebuilt kit.
ive got C3 & 13 cast into it, no other identifying info, I'll try & figure out the model.
 

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MacAttack

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I thought Zama was made in Japan or Korea? Did they move production at some point?
 
bkj110

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That Zama Chinese junk carb is actually the better of the two offerings for this model of saw- the Walbro was known to give problems.
NEVER transitioned- so you did not buy it new from a dealer? It came to you with this problem?
Proper cleaning (no high pressure compressed air!), proper full kit, correct assembly, mixture screws set to factory spec (both 1 full turn out from lightly seated should get you started).
Check manifold and the small impulse line for cracks- ideally pressure and vac test the powerhead.
Remove the chain, bar, clutch and oiler and run the saw- any different?

Rather rich at idle is probably not a great bet- adjust the L screw to give max revs at idle and then turn it out 1/8 to 1/4 so it is a little rich- but not rather rich. Rather rich on L might be causing fuel pooling and flooding as it transitions from the L circuit to the H.
The coil starting to peter out can also first show as some erratic tuning type issues.

This family is pretty simple and easy to work on, running well they are a great near 60cc saw and you got a Red one- they are always better! :p
I did buy that new from a distributor, but they're an equipment rental place, not a saw place. And yes it didnt run great from the start but it was usable. Which is why i habent ran it much at all. But its unusable now. I had one Jred saw shop 45 miles away but that guy retired late 2000s. No one else around, its Stihl saws in big box stores around here so you're on your own either way. I never thought coil, I'll check it. And go through your suggestions, thank you for the response, its appreciated.
 
Bob Hedgecutter

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I did buy that new from a distributor, but they're an equipment rental place, not a saw place. And yes it didnt run great from the start but it was usable. Which is why i habent ran it much at all. But its unusable now. I had one Jred saw shop 45 miles away but that guy retired late 2000s. No one else around, its Stihl saws in big box stores around here so you're on your own either way. I never thought coil, I'll check it. And go through your suggestions, thank you for the response, its appreciated.


Okay, so you bought it new and it has never been "right"- that is what warranties are for. :innocent:
Don't know how they do things over there- but over here, the shop would tune the new saw rich, hand it to you, you hand them a wad of cash and they tell you to come back after about 5 hours of run time and they then tune it properly.
If that had happened and it never went back- could be part of your problem. It is a chainsaw, not a dirt bike or snowmobile- they respond best to proper tuning, not rich for more power- they can only drink a certain amount of gas in those wee combustion chambers.

With a Zama fitted from new, I am guessing it has the metal band holding the manifold to the cylinder? Not the known to fail plastic one. Is it an E-Cat saw- green fuel filler cap?
As I said earlier- pressure and vac test would rule out a lot of other possible problems and put you back at the carb- which may or may not be at fault. I would put the carb mixture screws back to both one turn out from seated and see if it performs any differently. If it doesn't, remove all the bits from the PTO side of the saw and see if it acts differently- could be something binding up on that side that is stopping the saw pick up at low RPM but is overcome by higher RPM.
Does it run the same with the air filter off?
 
cookies

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If you blew into or on that carb with compressed air get a new one. these lil saw carbs have valves cast into their bodies that get damaged/destroyed by compressed air or even a full blast from a can of carb cleaner.
 
peak98

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I picked up a 359 a couple years ago that was doing the same thing. Replaced carb with the Zama c3-el 42 and it tuned/runs perfectly. I’m giving serious thoughts to having it ported as I like the size/weight and could stick a 24” bar on it if needed.
peak98
 
Bob Hedgecutter

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ive got C3 & 13 cast into it, no other identifying info, I'll try & figure out the model.

I keep forgetting about those "modern additions" around the mixture screws- if they are limiter caps- pull the damn things off and throw them in the bin- then try setting it back to one out from seated on both.
 
sean donato

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I picked up a 359 a couple years ago that was doing the same thing. Replaced carb with the Zama c3-el 42 and it tuned/runs perfectly. I’m giving serious thoughts to having it ported as I like the size/weight and could stick a 24” bar on it if needed.
peak98
I have a ported 359, 24" is pushing it. on it, it's happiest with 18/20". Ported it has little bit more power then a stock 562xp great saws but not power monsters.
I keep forgetting about those "modern additions" around the mixture screws- if they are limiter caps- pull the damn things off and throw them in the bin- then try setting it back to one out from seated on both.
Few thoughts, I agree with Bob, besides doing a kit. The zamas are cheap just get a new one. A pressure/vac test would be best to start with.
How did you fatten it up with the limiters on there? The little bit you can turn the jets with the limiter on isn't very helpful in tuning.
I thought Zama was made in Japan or Korea? Did they move production at some point?
They have been Chinese as long as I have ever known, they are good quality and I believe stihl owns them for a while now.

I did want to add that the walbro carbs are not that bad in these saws. They needed bit of work but do overall run better imo when they run right. One of the guys had a video on how to properly fix them, think it was the fuel pump diaphragm, and the hole to the metering diaphragm needed modified as well. Mines been cherry ever since.
 
Vintage Engine Repairs

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High circuit is full rich to the stop & it just zings once it does pick up

Get that stop off and give it some more fuel on the high. Steve
Not sure if this was a response to my comment? If so, Leaking H nozzel can create a lean symptom at idle and / or off idle, but not noticeable at WOT - it doesn’t leak fuel into the venturi, it leaks air back into the metering chamber.
If it’s not in reply to my comment, you can safely ignore it.
 
MacAttack

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I have a ported 359, 24" is pushing it. on it, it's happiest with 18/20". Ported it has little bit more power then a stock 562xp great saws but not power monsters.

Few thoughts, I agree with Bob, besides doing a kit. The zamas are cheap just get a new one. A pressure/vac test would be best to start with.
How did you fatten it up with the limiters on there? The little bit you can turn the jets with the limiter on isn't very helpful in tuning.

They have been Chinese as long as I have ever known, they are good quality and I believe stihl owns them for a while now.

I did want to add that the walbro carbs are not that bad in these saws. They needed bit of work but do overall run better imo when they run right. One of the guys had a video on how to properly fix them, think it was the fuel pump diaphragm, and the hole to the metering diaphragm needed modified as well. Mines been cherry ever since.
Have a looky at this Zama (C1?) from a 1970's McCulloch SP40:

And later... a Zama C2 from a 1990's Homelite stamped "Hong Kong".

It's a shame everything ends up getting moved to places like China.
 

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bkj110

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Yeah, I could have taken it back, at the time i just figured it was a mom saw, so shame on me for not researching more.
Not sure if this was a response to my comment? If so, Leaking H nozzel can create a lean symptom at idle and / or off idle, but not noticeable at WOT - it doesn’t leak fuel into the venturi, it leaks air back into the metering chamber.
If it’s not in reply to my comment, you can safely ignore it
Yep, I blew compressed air through the main body when apart, I'll buy a new one. Lesson learned. Flywheel has two magnets & coil has two pickups? Is this a multi spark deal? The larger side of the coil was cocked down to .012" clearance, the other side was .030". I squared it up the best I could, put a new plug on and pulled, spark looks good. I am used to carbs with an intermediate/midrange circuit, but I'm shooting for light tan on porcelain. Never felt the need to play with timing and I see its not adjustable anyway. Saw does have a green fuel cap. I'll do a vac/press test, I'll have to make some block offs to seal it up.
Okay, so you bought it new and it has never been "right"- that is what warranties are for. :innocent:
Don't know how they do things over there- but over here, the shop would tune the new saw rich, hand it to you, you hand them a wad of cash and they tell you to come back after about 5 hours of run time and they then tune it properly.
If that had happened and it never went back- could be part of your problem. It is a chainsaw, not a dirt bike or snowmobile- they respond best to proper tuning, not rich for more power- they can only drink a certain amount of gas in those wee combustion chambers.

With a Zama fitted from new, I am guessing it has the metal band holding the manifold to the cylinder? Not the known to fail plastic one. Is it an E-Cat saw- green fuel filler cap?
As I said earlier- pressure and vac test would rule out a lot of other possible problems and put you back at the carb- which may or may not be at fault. I would put the carb mixture screws back to both one turn out from seated and see if it performs any differently. If it doesn't, remove all the bits from the PTO side of the saw and see if it acts differently- could be something binding up on that side that is stopping the saw pick up at low RPM but is overcome by higher RPM.
Does it run the same with the air filter off?
 
sean donato

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Have a looky at this Zama (C1?) from a 1970's McCulloch SP40:

And later... a Zama C2 from a 1990's Homelite stamped "Hong Kong".

It's a shame everything ends up getting moved to places like China.
You got me there, I've never seen a zama that didn't have made in China stamped on it.
 
Bob Hedgecutter

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Yeah, I could have taken it back, at the time i just figured it was a mom saw, so shame on me for not researching more.

Yep, I blew compressed air through the main body when apart, I'll buy a new one. Lesson learned. Flywheel has two magnets & coil has two pickups? Is this a multi spark deal? The larger side of the coil was cocked down to .012" clearance, the other side was .030". I squared it up the best I could, put a new plug on and pulled, spark looks good. I am used to carbs with an intermediate/midrange circuit, but I'm shooting for light tan on porcelain. Never felt the need to play with timing and I see its not adjustable anyway. Saw does have a green fuel cap. I'll do a vac/press test, I'll have to make some block offs to seal it up.

Yep, the compressed air may well have (but may not have- depending on how liberal you were with it) screwed up the internal galleries.
New genuine off the shelf Zama's are not bank breakers and it might be a wise buy- A: you can swap your carb for a known good one for near the price of a repair kit- and B: You then have a spare carb for upgrading a Husqvarna 350 if you ever find one to build. :laugh:
If it is a "green cap" saw, you might want to get an old style non cat muffler for it as well.

So, pressure and vac the powerhead if you have the means to do so. (getting some age on it now and might have a leak somewhere). New Zama (genuine not a cheap flea bay copy) with the limiter caps removed. New muffler (can be cheap aftermarket) and see where that gets you.
 
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