MS440 rebuild, fail?

[benny3411]

Im having problems with a ms440 after a complete rebuild. new oem bearings an seals, all oem gaskets, new nwp crankshaft, new oem cylinder kit-thanks to lwhaples, oem piston bearing, new oem tank vent, oem fuel line, oem impulse line, new gas oil caps, i rebuilt the original zama carb, dual port muffler, new spark plug, oil line, all new rubbers everywhere, new intake, air filter. The saw will start right up, sounds fine, and then just dies. Ive tried richening it up a bit and it seemed to allow it run longer, but something aint right. Ive tried loosening the gas cap and it didnt seem to help any. I need to try a different carb, and coil. Ive search up an down with a flashlight and cant see any leaks anywhere on the saw. Could a air- vaccum leak cause this?

 

[Mad Professor]

Vacuum test might save you some time, if it is a vacuum problem.

Check places for leaks, intake boot to cyl, sleeve and washer for intake boot to carb both there? Gaskets and diaphragms in carb in correct order/orientation (some kits have parts for several similar carbs), metering needle/seat. Check cyl bolts all tight.

 

[traffic903]

Check for kink in fuel line when the carb is pushed all the way back to the boot. 044 known problem.

 

[jackjcc]

Make sure the metering arm is set right. Been there on a few saws, starts but won’t run, forgot to make sure it’s set right.


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[Conquistador3]

Rebuilding a Zama carburetor is like rolling a dice: it's all up to chance. Try getting a cheap Chinese carburetor for it to test the saw with: they are far cheaper than second hand units.

 

[benny3411]

I tried another carb today, and it still did the same thing. Ive played around with both carbs today, tried different things, ive set the metering arms on both of them- just level with the carb body, right? I put on another plug wire an boot. I took the fuel tank back off and inspected everything. I took the intake boot off and applied three bond to both it and the on the cylinder, let sit for awhile to tack up, then put the boot back on, I got the screw as tight as it would go. Here are a couple pictures, not that great though, if anyone spots anything let me know. There is one more thing I changed today, was just to late and hungry to try starting the saw afterwards, will try it out tomorrow, crossing my fingers hoping it will help, maybe someone will guess what it is, it was something simple.

 

[traffic903]

Fuel line?? Is it kinked?

 

[BonScott46]

I had the same if not a similar problem with my 10mm 044. Rebuilt the carb and played with the LA adjustment i think it is called and the low jet and seemed to clear things up. Can't remember if I opened or closed it a bit. I might have tuned around the problem but it runs well.

 

[benny3411]

I got it guys! It was indeed what I was hoping it was, just something simple. I changed it out last night. Sure made a difference, cant believe I overlooked it. Some aftermarket parts may work fine, but oem it always going to best, what I should of bought in the first place an I should of known better. Picture of part coming here soon..

 

[grizz55chev]

I got it guys! It was indeed what I was hoping it was, just something simple. I changed it out last night. Sure made a difference, cant believe I overlooked it. Some aftermarket parts may work fine, but oem it always going to best, what I should of bought in the first place an I should of known better. Picture of part coming here soon..

Impulse

 

[benny3411]

So here it is. I purchased this new fuel filter for the rebuild, didnt think much of it. All of you guys were giving me good starting point on what to check, I thank each every one of you. Last night I took off this fuel filter and blowed through it just to check, it was pretty restrictive. I went and got the old fuel filter and blow through it, the flow was much better, I knew right there that might be the problem. I put the old original fuel filter back on and now she running good! Im going to order a new oem fuel filter. Through searching on ebay I see these selling for over $11 a piece...I dont even know how people are using them, this 440 certainly did not like it.

 

[grizz55chev]

The weakest link,

 

[Poleman]

Just curious....is that an aftermarket filter? If it is I had the same issue with them. The inside filter material is garbage...it swells and let's nothing through. I took off the black end and removed it.....it just let the wire screen do the filtering....very unrestrictive now.
Just wondering.....

 

[benny3411]

Just curious....is that an aftermarket filter? If it is I had the same issue with them. The inside filter material is garbage...it swells and let's nothing through. I took off the black end and removed it.....it just let the wire screen do the filtering....very unrestrictive now.
Just wondering.....

Yes, aftermarket. I took off the black rubber end and pulled out that inner black foam material, put it back together and your right its definitely got lots of flow now. Im going to give it a try this way.

 

[Poleman]

Nice saw!!!!