Help with 041 carb

[Haywire Haywood]

I put a carb kit in while I was waiting on the pin so I hope that doesn't give me problems. I've never done that before and I just put the metering lever in as it came out of the package. It looked about like the one that came out as far as angle and such. One thing that was strange was that the needle that came out had a rubber-like tip and the new one was all metal. I put a kit in that freebie Shinny 500 this week and it's needle had a rubber tip too.

I started to, but I think it has carb problems. No power and it's spitting a lot of gas back onto the air filter. I have a wet spot the size of a silver dollar on the felt. I need to go back into the carb and see if the metering lever is out of whack. I did a search (hurray for me!) and found a nice diagram on how to adjust the lever. I put the 372 (gulp!) on the mill with the 28" bar and a loop of 3/8 full skip semi-chisel. That made better time than the 041 with LP ripping chain.

Couple of quotes from other threads for a bit of background.

Well, carb problems have come to pass it would appear. I did a search and Lake said that spitback was sometimes due to worn piston skirts... this is a NOS piston and cylinder so that rules that out. I checked the metering lever this morning and it's level as a diagram I found on a search showed. I fished the rubber tipped metering needle out of the trash and will put that back in later today to see if that cures an unknown needle-seat seal problem.

Is there anything else I should look at while I'm in there?

thanks,
Ian

 

[West Texas]

I've never had this problem on a saw; but, when its on a car, it usually means the timing is off. Has a mod been done to any of the ports?

My smaller Walbro carbs all have rubber tipped needles. Every now and then, one of these tips gets worn and needs to be replaced. I'd give the rubber tipped needle an eye ball inspection and if it looks OK, put it back in the carb.

 

[Haywire Haywood]

No mod as such, but the base gasket was NLA so I made a new gasket that is about 005 thinner before installation which would change the port timing a touch. Don't know if that would cause what I'm seeing. It starts fine, idles fine, revs to spec but has no power in the mill. 150lbs of compression, 2 tanks of gas through it since reassembly.

Ian

 

[Scooterbum]

How does it respond to the hi side adjust?Does it richen right up when you crank it open(forget the tach for this and use your ears for the burble)? Base gasket a little thinner should'nt be an issue.Ignition electronic or points?

 

[Haywire Haywood]

I'm quite deaf to burble. Try as I might, "burble" doesn't mean anything to my ears. I'm quite useless without a tach and only marginally useful with one. I've not had the flywheel off so I don't know if it's points or electronic.. how do I tell?

Ian

 

[Scooterbum]

A search for "041 ignition" will bring a wealth of knowledge.(not being smart or anything).

Where is your high side set at?
If you can't hear the difference,try it at 1 1/4,1 1/2, and 1 3/4 and see if you see a difference in torque in the cut.

What I gather from your posts is that it is falling in the cut like no power,is that correct?

 

[Scooterbum]

Shame your not closer,I'd say bring it over and we could put it in some wood and figure it out.

 

[Haywire Haywood]

Looks like electronic ignition. No adjustment holes in the flywheel.

As far as where the H was, I pulled the needles this morning to see if they were dirty and to give it a good squirt of cleaner down the holes to try to flush them and was startled to find it was under 1 turn out to achieve 9800 WOT rpm. I put it back in at 1 turn out, cranked it and it was way rich, by that I mean low RPM.

I failed to mention that it was running hot before which would indicate to me a lean condition and the needle position kinda backs that up. Why it wouldn't rev without leaning it excessively and at the same time spit back so much is a mystery.

Ian

 

[Frank Boyer]

Changr the fuel and impulse lines. Then readjust the carb. My 041 needed them every few years.

 

[Haywire Haywood]

Both hoses at the carb are new. Didn't change the pickup hose. Will look and see what kind of shape it's in, but I did change the fuel filter and I seem to recall it's good.

Ian

 

[Haywire Haywood]

I went back through the carb today. Completely disassembled it short of taking the welch plugs out and blew carb cleaner through all the passages. All clear. Set both needles to 1 turn out and it ran badly at about 8k and smoked like a mosquito fogger. Just for kicks I pulled the fuel pickup to check condition and it's a little soft but fine, no cracks or deterioration.

Any suggestions? It ran fine before I changed the cylinder to the super version.

Ian

 

[Fish]

Look at the ignition closer.

 

[Haywire Haywood]

Ok, will borrow a flywheel puller from somewhere and see what there is to see under there.

Ian

 

[Fish]

Where you at in Ky?????

 

[Haywire Haywood]

Richmond, about 30 min south of Lexington.

Ian

 

[andrethegiant70]

Hi, Ian, I suspect you've read what I have about the seal between the oil tank and the crankcase.....I would maybe dump most/all the oil out of the tank to make sure you're not getting oil into your crankcase...the "mosquito fogger" comment is of concern. Maybe just make sure you don't have TWO things going on at once.

 

[Haywire Haywood]

What is getting me is that none of this was disturbed during the change and wasn't an issue before. Four Paws said that there were several timing changes throughout the 041 line. Could it be that i need to re-time the ignition?

Ian

Maybe the mosquito fogger comment was a bit much. It smokes like it's running way rich and at 2k under spec at just 1 turn out on the H. I've had oil in the cylinder before and it doesn't smoke like that.

 

[andrethegiant70]

Maybe the mosquito fogger comment was a bit much. It smokes like it's running way rich and at 2k under spec at just 1 turn out on the H. I've had oil in the cylinder before and it doesn't smoke like that.

It seems that I remember that thread. Carb issues can sure be tough.... I recently rebuilt a Dolmar 110 carb like 5 times trying to figure out what was wrong with it, did the same thing you're doing, fooled with the inlet needle height, cleaned under and replaced the welsh plugs, the works.....everything on the saw told me it should run like a banshee. I finally shelved the thing 'till I found a replacement WT-76 carburetor (six months it took), rebuilt THAT one and the saw runs like new. Most of the time these carbs are esy to work with, other times they can be full of bad voodoo. I will say that its easy to understand why a carb may run lean, not so easy to diagnose a chronic rich condition.

Unfortunately, you need a real carb tech on this one or you need to swap out the parts for diagnostic purposes. I took door number two.

Oh, as a P.S., my philoosophy is generally that when a saw is working, then I work on it, and then the saw DOESN'T work anymore, I'm usually the culprit.... again, I suspect you've thought of this, but go make sure you've got the right diaphrams in the right place, and hit all the passages with carb cleaner (again).....remove and check the needle seats for contamination and deformation. Its certainly possible that you've dislodged some crud that has made its way to the next constriction.

 

[Haywire Haywood]

Hmmmm... I do know where another 041 carb is that I might be able to put on there.... don't I Dustytools.... MUAHAHAHAHA...

I need to go through all that info on 041 ignitions that Andy posted awhile back. Maybe I'll learn something there. Maybe not. I've had it downloaded for about a week now but haven't gone through it yet.

Ian

 

[Lakeside53]

What Andre said... Read up (AS search) on the oil pump leak issues...