Over a period of time, it has lost power, gotten harder to start, and now won't run. I can get it to fire for a couple of seconds at full choke, but it dies when moved to half choke and usually after a few seconds one way or the other. Squeezing the throttle seems to make no change to engine speed. The throttle cable is attached and is opening the throttle flap. It's acting like it's fuel starved or has an air leak. All the gaskets between carb and engine seem to be OK.
I've replaced fuel lines, fuel filter, and spark plug. I replaced gaskets and diaphragms in the carburetor using a kit left I had bought for my last, similar weedeater. All the parts fit correctly, but I'm not sure that is the correct kit. I double checked the Walbro illustration for the carb, so I think I have all the parts in the right places. I cleaned the carburetor as best I could with carb cleaner, but I don't have the tool needed to remove or adjust the needle pins. I cleaned the screen, metering needle mechanism, and all the passages I could get to. I've cleaned out the spark arrester. I mixed a batch of new gas. Its still won't run.
One other thing: the squeeze bulb won't squeeze. It works fine when disconnected, sucking on one side and expelling the other.
I have to admit I've never drained the gas between uses, even over the winter. I always use up the last batch of gas leftover from last year.
I've about convinced myself there must be a blockage or varnish around the needle valves. Am I on the right track? Any suggestions? Where would I get the special tool needed to reach the tiny splined, recessed needle pin heads? Is there a way to use carb cleaner fuel additive without damaging the engine?
Hello Waldroop!
Since you say the primer bulb won't work, then it is definitely a fuel problem. It won't push fuel out? What if you remove the return line from the carb? (the smaller of the 2 lines). Will it shoot gas out? Or is it having a problem pulling gas in? (when you push the primer, it doesn't return to the normal position).
Correct. With all lines attached, the primer bulb doesn't push gas into the carb. The bulb doesn't 'deflate' at all when squeezed.
By return line, I assume you mean the supply line from the tank to the carb. That's the smaller of the two lines. When that is disconnected, gas does not shoot from the carb when the bulb is squeezed. The bulb isn't deflating at all.
However, when the primer line is disconnected from the carb, the primer bulb works normally. It deflates and shoots gas out of the disconnected line, then refills from the tank.
I also checked the passage from the primer line into the metering chamber. It's clear. Primer gas is making it into the metering chamber.
Sounds like the return line is restricted. I was thinking the return line was the smallest of the 2, but could be wrong. The supply line goes to the tank and has the filter on the end, and connects to the suction side of the carb. The return line goes to the tank and has no filter on the end, and connects to the discharge side of the carb.
Hi Cheese,
That was an assumption the small line was a supply, but I'm wrong. Small diameter, no filter in the tank, and goes straight to the metering chamber, not through the pump diaphragm. Duh. That line is clear. I checked the passage in the carb and replaced the line.
Should gas shoot out of the return when the bulb is squeezed? I'll look again; maybe didn't put the pump diaphragm in correctly. I won't get to look at it agin until this weekend. Thanks for the help.
W
Not sure if anyone else is confused as I am or not but maybe time for some clarification...??
Best I can follow your terms waldroop, and please correct me as required...
Metering chamber = Carburetor....?
Pump diaghram = Primer bulb....?
I beleive the primer bulb is supposed to operate in the following manor....
When the bulb is deflated (pressed) it should expell out the return line which should go to the fuel tank with no filter, when the bulb reinflates it should draw through the carb from the supply line which runs from the fuel tank with a filter. If the bulb will not deflate (press) I would guess as cheese mentioned the return line is restricted OR possibly your lines are reversed and it is trying to expell through the carb in reverse direction it is intended to. Usually the lines and fittings are of different size to help prevent this, however it can and does happen.
If you remove the bulb press it, the fitting that blows goes to the fuel tank and is return, the fitting that sucks should go to the carb.
If I have made matters more confusing please ignore this post LOL
Hi Aziz:
Those are part names Walbro uses. Here's the diagram: www.walbro.comService and AftermarketAftermarket Parts and ServicePoulanTrimmerWT628 (Craftsman isn't listed, but the WT628 carb I have shows up under the Poulan 32cc trimmer.)
The metering diaphragm (#34 on the diagram) is the diaphragm in the carburetor which has the silver wagonwheel-shaped piece of metal attached in the middle.
The pump diaphragm (#32) is the diaphragm in the carburetor, on the opposite side, which has two horse shoe-shaped flaps.
The fuel filter in the tank is attached to the smaller fuel line which runs directly to the carb. A second, larger line comes out of the carb and runs to the bulb. A third line, also a larger line, runs from the bulb to the tank, but does not have a filter.
From what you say, part of my problem was that I had the lines on the bulb reversed. (I thought the bulb is supposed to push fuel INTO the carb.) I swapped them. Now the bulb is sucking fuel from the carb and squirting it into the tank. The bulb is pressing and filling like it should, but the motor still won't run.
I'm still thinking I have a blockage around the needle valves. I'd like to take the power and idle needles out (#49 and #50) and clean that area out, but I don't have the special tool. The needle heads are recessed, and there's not enough room for needle nosed pliers. One of Walbro's suppliers told me the special tool can't be sold to the public because of an EPA rule. @#^$!
I ordered a new carb. Thanx for the help!
W
That is what I was getting at with the lines. Are you certain that you have good spark?
No, I'm not certain. I put a new spark plug in, gapped to .028 per the local mower shop. Since it tries to idle for a few seconds at full choke, then dies at half choke, I'm assuming a fuel problem rather than a spark problem. Need to check that.
The best way I can think of is to remove the plug from the engine then reattach the plug cable and try to start with the plug against the block with the gap visible to see if it's arcing. Is there a better way?
W
That'll do it, but I'm with you that you probably have spark, or it wouldn't run at all. Have you verified that the exhaust isn't clogged?
While servicing the carburetor, did you replace the inlet screen? It is on the fuel pump side and will clog up over time. If you did not, by all means do so. This alone may solve your trouble but you may want to check the muffler and exhaust port for blockage as cheese suggested in the previous post.
Hi Cheese, Puey:
Yes, Cheese, I took the muffler/spark arrester apart. It was a little sooty, but not blocked.
No, Puey, I didn't replace the screen. I rinsed it off with carb cleaner, though. It had a small piece of something on it when I started, nothing significant, but it's all clean now (at least looking from the outside). I didn't know they came out. It looks pressed/swedged in, kinda permanent like. How do you remove/reinstall?
Thanks for the responses, guys. I appreciate the help.
W
You can just pick it out with a pin or sharp point of a knife. It just pushes back into place.
Cheese, Azis, Puey:
SUCCESS! The new carb did the trick.
Out of curiosity, I took the screen out of the old carb as you suggested, Cheese, and gave it a good cleaning. There is a pretty good drop in the amount of air I can blow through the carb with and without the screen. I can't see light through the screen. Should I be able to? Maybe that's the problem. I'll try to remember that for next time.
W
Glad you got it!
Some screens you can see through, some not. (some are thicker than others). It probably will restrict airflow a bit, but it shouldn't stop it.
Hi
If someone know where I can find the adjusting tool for the craftsman 32cc trimmer carburator
if not a normal screwdriver
thank
lunai1;
Please start a new thread, you will get little response tagging onto a post that is 4 yrs old. Have a good one. Geo
Tags: craftsman, 32cc, weedeater, return line, from carb, primer bulb, carb cleaner, fuel tank, line which, metering chamber, pump diaphragm
