Need Help Rebuilding Carb on Homelite 240 Saw

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  #41  
Old 04-24-20, 10:29 AM
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I suspect when you placed the metering arm fork above the needle valve and not in the groove and tightened everything down the metering arm was bent and can't work the needle valve properly. Or possibly the flaps on the pump diaphragm aren't properly located.

Take the metering arm out and lay it by the new one and take a look at the difference. You may have to guess an adjustment.
 
  #42  
Old 04-24-20, 11:38 AM
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does look like your needle is under the arm in one pic not sure if you put it together that way or not.
to replace a fuel line and filter you may need to disassemble some to gain access to where the line is entering the tank pull the old one out get a new one started it helps to cut the end at a angle use some lube on the hose so it can be pulled through easier and then pull it through the gas cap fill hole cut off fuel line and install filter.
new fuel line needs to be the same diameter most small engine repair places would likely have an equivalent size that should work they would also probably have a filter.
 
  #43  
Old 04-24-20, 01:19 PM
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Arrow Replace Needle and Folk

Okay ... I replaced the old needle with the new one and I swap the metering arm too. I was able to get it started. I put some fuel in the plug hole. It started for a brief second, then I used full choke and throttle until it finally started. It idled rough. I had to keep giving it throttle. For a short while it was able to idle on its own. I cut a few limb with it. It would stop on me at times, but I was able to start it again. While cutting it stopped on me, I added some more fuel although it wasn't empty. It was hard to start again, but I got it going holding the throttle. I cut a little more ... it stalled again. Got it started again briefly, this time it died while I was holding the throttle and I could not get it started again. Is it a matter of adjustments or is it something else?
 
  #44  
Old 04-24-20, 01:59 PM
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Just getting it started is a plus. It's something adjustment may take care of now.. Pop the limiter caps off the mixture screws and take both of them out. Spray a little cleaner in both screw holes and spin the engine over a couple times with the pull cord.

Clean up the area around the screw fittings and reinstall both of them. Turn both in until lightly seated, then back out 1 1/2 turns. See if it will start and idle on those mixture settings with the throttle stop screw where it's at. If you need to, adjust the stop screw to keep it running.

Now adjust the LH screw for max rpms. That should let it run and snap the rpms up when you open the throttle. If it bogs when throttled adjust the LH screw to correct. It should snap right into the higher rpms. With a responsive throttle and it idling, turn out the LH screw slightly.

Post back.
 
  #45  
Old 04-24-20, 07:11 PM
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Question How to?

Okay how do I remove the limiter caps? Are you saying once the limiter caps are off take out the adjustment screw and put cleaner in the holes? The limiter caps would still be removed while I turn it 1 and 1/2 turns. I would have to install the carb with the limiters off to see if it will start? Then I would have to remove the carb again to install the limiters? Am I getting this right? How would I adjust the LH screw for max rpm?
 
  #46  
Old 04-24-20, 07:24 PM
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You should be able to remove the limiter caps - they're usually just stuck on the screws. Different makes have them a little different. Unscrew both adjusting screws. Don't plan on putting the caps back on.

With the screws set at 1.5 turns out from lightly seated and the engine idling turn the LH screw in/out to achieve max rpms.
 
  #47  
Old 04-29-20, 06:41 PM
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Arrow Okay Removed the Limiters

I pulled off the limiters, took out both screws, shots some cleaner down the holes, put the screws back turning them all the way in, then backed off 1 and 1/2 turn for both high and low. It tried to start after choking it and holding down the throttle, started up and I push the choke off, then it stalled. Tried starting it again just holding the throttle, acted like it wanted to start. It got hard to pull the cord at times, then I realized I had the choke on and probably flooded it. I didn't put any fuel in the plug this time so I made progress. I will try again tomorrow.

I seem to be leaking fuel ... don't know where it is coming from, but I see it next to the saw.
 
  #48  
Old 04-29-20, 07:10 PM
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Did you adjust the throttle stop so it would keep running at idle and and adjust the LH screw for max rpms? That has to be done with the engine warmed up and the choke off. If it won't run with the choke off, turn the LH screw out a little at a time until it continues to run, then do the max rpms adjustment.

The leakage is probably coming from either the pump screw or the four reservoir screws being loose.
 
  #49  
Old 04-29-20, 11:54 PM
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Question Throttle Stop?

Is that the third screw on the carburetor? If so how would I adjust it to keep the saw going? So I am suppose to keep adjusting the other two screws until it runs smoothly ... correct?
 
  #50  
Old 04-30-20, 12:22 AM
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the base idle screw just opens the throttle plate and causes it to idle higher it may not help to keep it running if the L screw is way off.
the L screw is low speed mixture should be adjusted at idle, highest rpm may be fairly close sometimes you need to go slightly richer to prevent stumble when you hit the throttle.
the H screw is high speed should be adjusted at full throttle really do not want the highest rpm in this case as it is to lean, you want to richen it by turning it out the engine will sound like a 4 stroke or kinda skip a beat but this ensures you are getting plenty of fuel witch is the only lubrication the engine gets. thats about as good as you can do by ear.
would probably look into your fuel leak first if your pulling in air from anywhere its going to affect your mixture.
 
  #51  
Old 04-30-20, 05:42 AM
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The 1 1/2 turns out gets you in the neighborhood. You use the throttle stop to keep it running to adjust the mixture. Leave the H screw alone for now. It can be difficult to set for max performance if you're dealing with the engine running wide open. And there's other ways to get it close for what you're doing.

The low speed mixture gives you the transition from low to the higher rpm range. Typically the 1 1/2 out is close. Depending on the condition of the saw you may go slightly in or out to get an acceptable throttle response. Often, not always, you have to lean the mixture, turning the L screw in. Up to a combustion threshold, the leaner mixture is more responsive. Past that point it's all downhill.
 
  #52  
Old 04-30-20, 05:14 PM
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Arrow A Bit Confused

Okay I'm still not sure what the throttle stop is and how I am suppose to adjust it. I want to make sure I understand so I don't have to keep pulling on the cord. It seems to slip at times when I am pulling it. I see what you are saying about the L screw, just need clarification on the stop.

As far as the fuel leak I don't know what to do in order to find and correct it. The videos I find are showing how to change fuel lines in newer saws, can't find anything on mine.
 
  #53  
Old 04-30-20, 09:00 PM
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If you look at the side of the carburetor when you work the throttle you'll find a screw the throttle arm stops against. It's usually tapered so turning it in/out moves the throttle. Clockwise typically open the throttle, increasing the rpms.

It doesn't directly affect mixture.
 

Last edited by marbobj; 04-30-20 at 09:23 PM.
  #54  
Old 05-10-20, 07:02 PM
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  #55  
Old 05-11-20, 05:37 AM
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The TAS is the throttle stop screw. (the acronym stands for Throttle Adjusting Screw. That one is tapered where the throttle arm comes to rest for an idle. If it's not seating, it may have been over torqued and the threads are stripped. Will it turn out the other way (counter clockwise)? If it will take it out and check the threads in the bore it screws into.

Were you able to seat and set the two mixture screws ( the "L" and "H" screw)?
 
  #56  
Old 05-11-20, 10:39 AM
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really no reason to seat the throttle screw seen many carbs break the casting off the carb from overtighten that screw it really just opens the throttle plate one turn can make a big difference in rpm if your engine was running but yours is not.
if you dont have the carb off go back and look at your pics of the throttle screw see the tapered tip screwing it in just moves the throttle shaft arm to a larger section of the taper opening the throttle more you shouldnt ever need to turn it in till it stops against the carb body it wasnt designed to be seated.
 
  #57  
Old 05-11-20, 11:48 AM
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Arrow Yep on the H L screws

Yes I was able to seat the L H screws and I gave them two full turn like the video stated. I will check the TAS screw when I can and report back.
 
 

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