Homelite 410 carby problems

[cbfarmall]

I'm about at my wits end on this one. Working on one of my 410s, real clean saw. Replaced the boot and fuel/impulse/oil lines, rebuilt the carby with new gaskets and diaphragms. Now, I'm trying to start it and the only way she'll run is if I prime the carb. Dies quickly, every time. Pulled the carb apart again, checked the gaskets, inlet lever, it's super clean inside but dry. Seems like the carb won't pick up fuel. Impulse is pulsing. I siphoned some fuel thru the line just to fill it up. I tried filling the chambers of the carb with fuel and reassembling. Still won't run without priming. For the hell of it, I pull the carb off my other 410 that I picked up yesterday. Saw fired right up and idled beautifully. If I straighten out the carb, I'll have a real runner.

FWIW, the carb I can't make work is a WS-22 and the other good carb is a WJ-5, both for 410s. Go figure that out.

What do you think?

Chris B.

 

[Modifiedmark]

Chris, my 410 has a WS carb on it and I couldnt get it to run after the same things you have done. New boot, lines and carb kit. I have to admit that I traced it down pretty fast though. I had the impulse and fuel lines reversed!

So I'm not sure I'm qualified to help you much.


Seriously, that was my first trip inside a WS that I can remember anyway so I'm happy it will at least run.

I thought it ran pretty good too, till I run into Mopars Poulan 4200 at that gtg. Oh well I still like it.

 

[Erick]

I thought it ran pretty good too, till I run into Mopars Poulan 4200 at that gtg. Oh well I still like it.

I get the feeling that happens a lot.

I was pretty impressed the first time I picked that thing up.


Cb, does your WS carb have the "ring" built onto the carb to stiffin the intake boot??? I have seen (and done) the carb boot get pushed aside when installing that carb causing a huge air leak. I replaced mine with a different carb and a ring from a stihl.

The 410 is not one of my favorite Homies to work on. :bang:

 

[cbfarmall]

Chris, my 410 has a WS carb on it and I couldnt get it to run after the same things you have done. New boot, lines and carb kit. I have to admit that I traced it down pretty fast though. I had the impulse and fuel lines reversed!

You know, I would have said the lines are in the right order because both saws match, but the carbs are not the same. I'll try swapping the lines, for the hell of it and because its easy. That would certainly explain alot. Never had a carb give me this much trouble.

Cb, does your WS carb have the "ring" built onto the carb to stiffin the intake boot??? I have seen (and done) the carb boot get pushed aside when installing that carb causing a huge air leak. I replaced mine with a different carb and a ring from a stihl.

I've been pretty careful about making sure that ring seats in the boot. Besides when I swap carbs the problem disappears. I like Mark's solution, although it makes me look kind of stupid.

I'll report back tomorrow.

I agree, the 410 is an oddball, but you love 'em for their defects. Heavy as hell, especially when compared to its big brother 540, plus it has a 4 reed pyramid. What was Homelite thinking? Still, I bet it's a monster among its peers.

Chris B.

Chris B.

 

[cbfarmall]

Update: I tried swapping lines with no effect. Put another new fuel pump diaphragm in, no effect. Noticed the new circuit plate gasket was different from the old one, so I put the original back in, no effect. I see fuel in the line, but it is not being pumped by the carb. Only option I can think of is to reinstall the working carb and re-verify the saw will run and cut that way. Then, I'll be looking for another carby. Maybe I have a monster airleak...

I'll find out my next day off.

Chris B.

 

[Modifiedmark]

Chris, if you want to try another WS, let me know and we can pull the one off of mine. We can open it up and compare them also.

I'm off friday though sunday this week.

 

[cbfarmall]

Chris, if you want to try another WS, let me know and we can pull the one off of mine. We can open it up and compare them also.

I'm off friday though sunday this week.

Mark, unfortunately I'm working Fri thru Sun. Still, I'm off the weekend after and have vacation Labor Day weekend. I ought to come pay you a visit just the same.

Back to the saw, I did swap carbs and just as I suspected, the WJ works well on both saws and the WS not at all. I got a suggestion for further troubleshooting and I'll pursue that tomorrow. At least I confirmed the saw itself is in sound condition.

Chris B.

 

[JRS350]

Mark, unfortunately I'm working Fri thru Sun. Still, I'm off the weekend after and have vacation Labor Day weekend. I ought to come pay you a visit just the same.

Back to the saw, I did swap carbs and just as I suspected, the WJ works well on both saws and the WS not at all. I got a suggestion for further troubleshooting and I'll pursue that tomorrow. At least I confirmed the saw itself is in sound condition.

Chris B.

I know this is an old thread. But this is an old saw so...

I'm in the same boat as CBFarmall. I tore my saw down and cleaned it up. It sat way too long in the barn and was in a flooded basement. It has spark (I baked the coil in the oven for 30 min at 225f). It runs like a champ for 10 seconds on a shot of starting fluid.

New lines, new boot, new filters.

I rebuilt the carb three times, modified the diaphragm on the third try, thinking a hole was needed under the fuel inlet nozzle. The carb holds vacuum and pressure, and shows no bubbles when pressure is added and I dunk it in a bowl of fuel.

I can see fuel in the line (new clear yellow tygon) the inside of the carb is dry.

I have pulse pressure and no real leak in the crankcase: checked by placing a piece of rubber between the muffler and port, then pumping 20 psi into the impulse line. It holds for several minutes.

Three Questions:

1.) What should I try next?

2.) What other saws have the walbro WJ5 carb?

3.) Erick, (or anyone else) what Stihl carb would work as a replacement?

Thanks in advance! I've rebuilt several trimmers, augers, and my Stihl TS-350 that led me to tackle this unit.

Best, J

 

[ferrina]

I know this is an old thread. But this is an old saw so...

I'm in the same boat as CBFarmall. I tore my saw down and cleaned it up. It sat way too long in the barn and was in a flooded basement. It has spark (I baked the coil in the oven for 30 min at 225f). It runs like a champ for 10 seconds on a shot of starting fluid.

New lines, new boot, new filters.

I rebuilt the carb three times, modified the diaphragm on the third try, thinking a hole was needed under the fuel inlet nozzle. The carb holds vacuum and pressure, and shows no bubbles when pressure is added and I dunk it in a bowl of fuel.

I can see fuel in the line (new clear yellow tygon) the inside of the carb is dry.

I have pulse pressure and no real leak in the crankcase: checked by placing a piece of rubber between the muffler and port, then pumping 20 psi into the impulse line. It holds for several minutes.

Three Questions:

1.) What should I try next?

2.) What other saws have the walbro WJ5 carb?

3.) Erick, (or anyone else) what Stihl carb would work as a replacement?

Thanks in advance! I've rebuilt several trimmers, augers, and my Stihl TS-350 that led me to tackle this unit.

Best, J

When I rebuilt mine the main brass fuel nozzle that comes up into the venturi was clogged really bad so I had to use wire to ram it through to clean it out that worked for me.