Am ms440 carbs

[MustangMike]

Now … how do you know all this???

 

[Wonkydonkey]

Know what... fat smoking oily hoe,s


My mate told me and I believe him..

Or the. AS threads.. on flame front , timing etc

Btw pop off pressure plays a part as well.
..I’ve changed the spring so maybe I will not have to change it back...to the am spring..

 

[Pincher]

I had to look up pedantic. Wonkydonkey sure has a way with words.

 

[huskyboy]

I’m gonna suggest the solution no one wants to hear in this thread... buy a new OEM carb or rebuild good used one. Aftermarket carbs are a shot in the dark imo. I’m curious as to why you swapped a good running zama off the saw if it was working fine?

 

[Pincher]

For me the aftermarket kit saws were an investment in my education of chainsaws. Not sure I wanted to learn as much as I had to. Two of the three kits turned into fine firewood saws so far.

 

[MustangMike]

I have had many good running AM carbs, but I will not spend my time playing with a bad one … there are just too many things that can go wrong.

 

[MustangMike]

For me the aftermarket kit saws were an investment in my education of chainsaws. Not sure I wanted to learn as much as I had to. Two of the three kits turned into fine firewood saws so far.

I hear ya, for me it was a way to learn how to port saws w/o ruining any good OEM cylinders!

 

[Wonkydonkey]

I’m gonna suggest the solution no one wants to hear in this thread... buy a new OEM carb or rebuild good used one. Aftermarket carbs are a shot in the dark imo. I’m curious as to why you swapped a good running zama off the saw if it was working fine?

Well if TM knows a thing or two, I’m just testing his theory’s but with an affordable carb.
Btw. I have a European 044.

I hear ya, for me it was a way to learn how to port saws w/o ruining any good OEM cylinders!

I agree with you about porting and learning with cheap Am cylinders. I know carbs can be a pain. But I wouldn’t learn much in problem solving if I was to just buy an expensive oem carb. And then find I’ve still got a problem... and if I got what I said last night right. Then all will be great experience and I will remember..it.
Cheers.

 

[huskyboy]

The bore on the aftermarket carb was smaller than the oem HD16 I had on the 440 here. I believe it was copied after the zama.

 

[Wonkydonkey]

I managed to look and play, although it was a bit late.

I put the timing back to stock. The carb ran better, it was more tuneable, then I ran into the leaning out at wot... so I never got to put into any wood..

Yes,,, at some point swapping carbs I pinched the fuel line and it’s got a pin prick/pinch hole.

I thought I ordered a new one with all the other bits,,,but it seems like I forgot..

I did get a pic or , and have a few questions to ask others...

I’ve noticed there seems to be 2 types of Am carbs on the bay.. the difference is the throttle butterfly. Either one cutout or 2.
And I’ve since come across the sticking choke thing that mustang mike was saying before. If I tighten up the carb bolts the choke sticks on, when the nut is undone a bit it springs open.
The only way round this I can see atm, is to use self locking nuts (nylon tops)
Carb pics from eBay. The first pic has the cutout near the impulse line so must have another at the top because that’s where the L speed fuel holes are. The other 2 pics clearly have one.

I’ve read what Terry Syd says about tuning and adding another cutout on the opposite side to the LSpeed jets,
My carb is as follows




So which carb do you guys have and is one more better than the other...

As for the low speed fuel holes I’ve got a few Q's about these.. but it will have to wait as I’ve got other things to do

 

[MustangMike]

I don't think I've seen any with 2 holes, OEM or AM.

 

[MG porting]

My two AM carbs are more less like yours.

 

[Wonkydonkey]

I will say there seems to be more pics of the one with 1 cutout. huzlt show it with one but sent the one with 2 cutouts.
I don’t think it’s a problem. I was just highlighting what I noticed, and for others to compare. Just maybe they are a bit different and from a different manufacturer?..
Also it seems some have the “HD” on the side and some don’t.
Here’s another one.
https://www.ebay.co.uk/itm/Harbot-M...971349?hash=item44503d4f15:g:tz8AAOSwtgxeDSzy

 

[MG porting]

And finally got all the recoil parts and yeah I put a elasto on as well hopefully this will help keep all the guts from blowing apart this time and will definitely be easier on me as well. Lol. Back to testing and modafying carbs.

 

[Pincher]

Mine only has a notch on one side of throttle plate.

 

[Pincher]

Found my oiling problem.

Prior to disassembly, I test ran saw to check if anything changed since it shut off on me last time. The saw Idled on its own but higher RPM than it should. I tipped saw clutch side down and saw slowed down and shut off. The air leak between crank and sleeve returned. Removed clutch and found the worm pictured above. I installed an oring behind sleeve this time.

Since I removed carb to check plate, I decided to up the pop off pressure being the idle mixture screw was only 1/2 turn out. I bent the metering lever to compress the spring a bit more. The lever height ended up aprox 1/16 inch lower than the body casting.

Reassembled and tested, it idles and the screw is now around 1 1/4 turn out. Not sure if air leak or carb adjustment fixed it.
It barely pumped oil until i discovered the pump was set to min.
Will be testing saw in wood this weekend.

 

[MG porting]

These dang carbs are really ticking me off just when I think I got it nope.

 

[huskyboy]

These dang carbs are really ticking me off just when I think I got it nope.

Oem lookin better by the moment? Nuffin wrong with oem other than the price lol. Good thing lots of different carbs fit 1128’s....

 

[MG porting]

Oem lookin better by the moment? Nuffin wrong with oem other than the price lol. Good thing lots of different carbs fit 1128’s....

Yes it's frustrating that's for sure there's something differently funky with these AMs can't wrap my head around it.

 

[MG porting]

So after countless hours and some days of mods on the two am carbs I call it quits for them although they still work but but there still crap just don't get it I put the hd17a back on the saw and runs perfect so now for something different or I should say should run the same after drilling out the jet to .68 it should run just as good as the hd17a im going to give this hd18b a try just because I can. But going to put a rebuild kit in it tomorrow or Saturday and give it a go.