Homelite 360 Keeps Flooding Out

[camer_1107]

Hello everyone. I recently bought a Homelite 360 because to me it seemed like it was to good of a deal to pass up. When I went to pick it up the guy couldn’t get it started so he knocked off $20, making it only $80 total.

I found that the saw only ran when gas was sprayed down the carb. The reason ended up being the intake boot was brittle and broken in pieces causing a massive air leak. I replaced the boot the other day.

The problem now is that every time I try to start the saw, there is an excessive amount of fuel coming out of the carb. Sometimes I can get the saw to run, but only with choke full off and the throttle fully open, and the saw only barely runs above idle speed. When this happens, there is fuel misting and spraying out of the top of the carb like a little fountain. I have replaced all the carb gaskets and diaphragms, replaced the needle valve, and tried my best to set the needle height adjustment to the right level. The thing about the needle adjustment that I’m not to sure on is that from what I understand, according to the walbro manual for the hdc carburetors, it sounds like you need to set the needle lever height to being level with the carb body with the float gasket on the body using a straight edge. Does that sound right? In other words, the gasket needs to be on the body when the straight edge is being used, and then the needle lever is set to being level with the bottom of the straight edge.

Other than this, I’m not quite sure what I’m missing. The fuel system for this saw seems deceivingly simple, so to me there doesn’t seem like there could be too many things causing this problem. Maybe the internal check valve is somehow damaged, or there is debris inside holding it open?

Let me know if you guys have any advice or similar experiences. Thanks in advance.

https://www.walbro.com/wp-content/uploads/2016/01/HDCseries.pdf

 

[Jasonrkba]

Make sure the gaskets and diaphragms are in the right order. Thats a common mistake.

 

[Old2stroke]

When you say "top" of the carb, is that the pump cover or the metering diaphragm cover? Most likely something wrong with the fuel pump diaphragm/gasket. When you have issues with adjusting the inlet control lever, you really have to have a way to pressure test the inlet valve to verify adjustments. If you don't have the right device, just hook a tube to the fuel inlet and blow into it, if the diaphragm is letting the inlet valve close, you should NOT be able to blow into it. If it's held open, flooding will occur.

 

[camer_1107]

Make sure the gaskets and diaphragms are in the right order. Thats a common mistake.

I’m pretty sure I’ve got all the gaskets and diaphragms in the right order; I’ve been using the exploded diagram of the carb from the manual I linked in my first post.

I took a closer look at the walbro diagram last night after I made the first post, and I noticed that there is supposed to be two circuit plate screws, but I have only one for some reason. I also observed that the gaskets and diaphragms I replaced didn’t look that old. That kind of tells me that someone may have been in this carb before me and goofed it up and lost one of the screws. Not sure if having only one screw would cause an issue, but I’m not going to rule it out.

When you say "top" of the carb, is that the pump cover or the metering diaphragm cover? Most likely something wrong with the fuel pump diaphragm/gasket. When you have issues with adjusting the inlet control lever, you really have to have a way to pressure test the inlet valve to verify adjustments. If you don't have the right device, just hook a tube to the fuel inlet and blow into it, if the diaphragm is letting the inlet valve close, you should NOT be able to blow into it. If it's held open, flooding will occur.

When I say top, I was referring to the top relative to how the carb sits when it’s mounted in the saw. I meant that a mist of fuel was spraying out of the main throat of the carb past the choke shutter and into the air filter chamber, seemingly the opposite direction of where it should be going.

I will for sure try that pressure test method though.

 

[Old2stroke]

Even though that saw is listed as being piston ported, spitting back through the carb is a sure sign of an engine that has reed valves that aren't closing and that horizontal cylinder design usually comes with reed valves. Can you confirm this? You would have to look through the carb with throttle and choke wide open and see if you can see the piston going up and down. If it is piston ported, there is something seriously wrong with the piston skirt or rings, that will produce a lot of spit-back through the carb.

 

[singinwoodwackr]

A tiny piece of crud in either needle screw will do this.
Rebuild the carb and make sure the is no damage to either needle, they aren’t bent, and everything is Uber-clean with carb cleaner. (Don’t use carb cleaner on any rubber pts!)

 

[camer_1107]

Even though that saw is listed as being piston ported, spitting back through the carb is a sure sign of an engine that has reed valves that aren't closing and that horizontal cylinder design usually comes with reed valves. Can you confirm this? You would have to look through the carb with throttle and choke wide open and see if you can see the piston going up and down. If it is piston ported, there is something seriously wrong with the piston skirt or rings, that will produce a lot of spit-back through the carb.

That doesn’t sound good. And yes there are no reed valves on this saw.

A tiny piece of crud in either needle screw will do this.
Rebuild the carb and make sure the is no damage to either needle, they aren’t bent, and everything is Uber-clean with carb cleaner. (Don’t use carb cleaner on any rubber pts!)

Ok, I’ll see if I have time to take the carb apart and go through it again tonight.

 

[singinwoodwackr]

I've had to replace t 455 rancher carbs of late with bent needles. Ordering the needles was a non starter...can't get anything from the local dealers, Husqvarna right now.

 

[Jasonrkba]

Those kits come with two of the round gaskets. This is from the IPL for your saw. Make sure the correct one is in it. #15.

 

[hotshot]

No reed valves used on the 360 saws, so you very well may have a worn out piston on the top/intake cylinder side if it was used with no air filter.

Don’t measure & set the metering lever height w/ the gasket on it, just a bare carb. Likely it’s set way too high now.

The circuit plate gasket you need to install is pictured below, assuming it’s still using the HDC-39A carb. Good luck with the repair!

 

[Old2stroke]

A tiny piece of crud in either needle screw will do this.

Actually it would cause a lean condition, the opposite of flooding.

 

[camer_1107]

No reed valves used on the 360 saws, so you very well may have a worn out piston on the top/intake cylinder side if it was used with no air filter.

Don’t measure & set the metering lever height w/ the gasket on it, just a bare carb. Likely it’s set way too high now.

The circuit plate gasket you need to install is pictured below, assuming it’s still using the HDC-39A carb. Good luck with the repair!

View attachment 1152956

Thanks for posting that picture, I saw that were two different circuit plate gaskets in the kit and I wasn’t sure if I had the right one in or not, but you have confirmed that I do have the right one.

Thanks everyone for the helpful replies. Unfortunately I’ve just been too busy to work on this saw over the past couple days, but I should be able to on Wednesday and I will provide an update then.

 

[Jasonrkba]

If the needle arm has the forked end make sure to insert the button of the diaphragm or it will definitely flood.

 

[camer_1107]

If the needle arm has the forked end make sure to insert the button of the diaphragm or it will definitely flood.

Do you think you could elaborate on this? I’m not quite following regarding inserting the diaphragm button.

Here’s an overall update:
I decided I didn’t think it was a good idea to troubleshoot using a carburetor with missing parts, so I ordered a rebuilt hdc39a carburetor from eBay. I originally intended to just swap a circuit plate screw from the new carb to my old one, but once I got it I thought I may as well just give it a try first. I looked inside the new one to make sure it was really rebuilt or not, and it looked good. The needle lever also looked to be set perfectly, and the right circuit plate gasket was in there. I put it in the saw and set the L and H screws to 1-1/4 turns out and set the choke to full. When I tried to start the saw it immediately flooded without running. I then took the spark plug out and dried it off. When doing so, I did a compression test (which is one of the first things I should have done when I got this saw ). The compression test came out above 120 psi, which, correct me if I’m wrong, I think is proof against it being an internal engine issue. I put the plug back in and the saw ran poorly, only with the throttle and choke completely open, and there was a ton of excess fuel. I only got it to rev decent when the screws were set to nearly 1/4 turn out, but the saw wouldn’t run for very long this way.

Maybe I’m just jumping to conclusions here, but does this seem to rule out the carburetor being the issue? Either that or the new carb isn’t a good candidate after all and I should stick to the original plan of swapping the circuit plate screw and making the old one work.

Also, is there any possibility that this is ignition related, to the point that the saw is misfiring so much that it keeps flooding itself? If so, does anybody know a good way of testing the ignition system, given the way they have the coil/spark plug set up?

I guess in my mind there doesn’t really seem to be that many things that could cause such an issue on an engine like this, but I am probably wrong, or at least it is looking that way.

 

[Jasonrkba]

View the ipl I posted, zoom in on piece number 1. The end of the arm slips around the little button in the middle of the bottom of the metering diaphragm. So long as the IPL matches the year/model saw you have.

 

[Jasonrkba]

I pulled up the kit for your saw and it does not appear to have that type of diaphragm so this will not be your problem. Sorry for the added confusion. About a month ago Leon did a real nice video on HDC rebuilds. It may be worth checking out.

 

[camer_1107]

I pulled up the kit for your saw and it does not appear to have that type of diaphragm so this will not be your problem. Sorry for the added confusion. About a month ago Leon did a real nice video on HDC rebuilds. It may be worth checking out.

Yeah I understand what you’re trying to describe now, but as you said this carburetor is not designed like that.

I’ll see if I can find the video you’re referring to, and take a look at some other ones as well.

 

[hotshot]

120# is too low to cut with, likely why it was sold.

Those are high compression saws in their day, and used part #12040 thin 0.024” piston rings.

The factory compression spec was 140-170# cold, per the Homey service manual.

 

[Old2stroke]

Did you pressure test the carb before installing it?

 

[OnlyHomelites]

As noted above, the best place to start is pressure testing the carb. Based on your description of what's happening while running, it's getting way too much fuel. The procedure you outlined for setting the fuel inlet arm height is correct, but if someone installed an aftermarket diaphragm with an incorrect nub, it won't matter. This video details that situation (too common):

The other thing to inspect closely is the main nozzle check valve. If the rebuilder of the carb used carburetor cleaner or other harsh chemicals, the original valve could have deteriorated. This video details the easy way to check it:

120PSI is a bit low, but it will still run just fine...that isn't the problem. Generally the ignition on these saws is all or nothing; good or bad. I haven't personally run into anything in between.