XL won't run after carb rebuild

[barney]

XL mid 70s build. I don't know the history of ownership.

It has a walbro-42 (date stamp 11/77). I replaced fuel lines, duck bills in fuel and oil tank. The carb seems to hold pressure. I cleaned carb and tiny holes with wire. The float lever was set even with the carb body.

When I'm pulling the starter rope I see fuel exiting the muffler. When it fires after about 10 pulls it revs wide open for 4 seconds and dies. I'm thinking it is flooding out. Should I lower the float lever?

Thanks in advance for any input

barney

[Homelite Homer]

Hello Barney, What are your mixture needle settings ?? Turn the Lo speed needle all the way in then back out 1 1/8 turns. Do the same to the high speed but back out 1 1/4 turns and try that first before you remove the carb again..

HH

[barney]

The Walbro-42 high is fixed (no needle to adjust), low side 1 or 1-1/4 no go.

I have another diaphragm I'll try that I filed the nub down.

For now, I'll let it sit for a couple of days.

Thanks for the reply.

barney

[bobby167]

You could be on right track. I had that problem with cheep carb kits. Nub was just a little higher., when i matched with oem kit. You can file it down. I just replaced it with factory carb kit.

[Homelite Homer]

Well now that you mention it.. I forgot all about the ONE SCREW Carb.. I had one of them on my XL and never could get it to run right until I switched it with a HDC off of a Super EZ.. Had to swap the throttle shaft out but after that I never had any problems again and it ran sooooo much better.

Good luck !!

Darryl

[barney]

Well, I change out the metering diaphragm and fuel poured out of exhaust, then adjusted needle lever and not enough fuel, then readjusted again and the engine just revs high and dies.
Maybe I should dig into the check valve and see if that is defective. Would that cause a hard to start condition? In one of Leon's videos the rev and die issue is related to idle circuit with the wrong circuit gasket. I have the correct one in there and those tiny holes are clean. There is a tiny brass jet there also that I ran a fine wire in there about an inch. I have no idea where that terminates. The other 3 tiny holes go into the throttle body.

I can take this apart quick now. LOL!

[barney]

Well, I got a free rental compression tester from autozone and it shows 60. I guess I have a problem. I looked in the exhaust port and I didn't see any scoring.
I tested my Homelite 360 and it was 130.
What should I be looking at next? If it revs high and dies why would the compression be low? I had to use teflon tape on the compression adapter for the XL to seal the plug hole because the adapter was to long and I was afraid it would hit the piston.Maybe it didn't seal well.
Back to square one.
Any ideas?
Thanks,
Barney

[Homelite Homer]

Barney it sure does sound like that compression tester you had was not a good fit.. I would NOT trust the results at all. If it feels like a normal pull when starting it is probably ok.. If it feels really really easy to pull then you may have issues. But it does not sound like a compression issue to me. To bad you didn't have another carb to put on there just to see if that makes a difference because it sure does sound to me like a carb issue. An easy test on the chk valve is to put a piece of fuel tubing over the valve opening and blow into the tubing using your mouth and then suck in.. only one direction will have easy flow the other should not have any flow and if it does then the valve is bad. Do you have the XL IPL ? the IPL will show the correct installation of the carbs internal gasket placement so have a look at that as well. It really is difficult to diagnose a problem like this via text on a forum so we all do the best that we can. LMK how you make out.

By the way.. Your thread heading says " XL won't run after carb rebuild "   Did it run before you did the rebuild ?  

Darryl

[barney]

No it did not run.

[barney]

I pulled the carb and removed the retaining ring and screen from the check valve. It was fine.

My next move is finding another compression tester to verify the 60psi I got the first time.

If it's still at 60psi should I change out the piston ring?

Thanks
barney

[barney]

Good news. The new compression tester reading came in at 119psi.

Back to the carburetor.

The next rainy day I'll have another go at it.

Thanks Homelite Homer

[Homelite Homer]

You are welcome Barney...Not a terrible reading... Would like to see it at 150 but it is still over 100 psi which is acceptable. A new set of ring may get you up a few PSI but what really matters most is the condition of the cylinder itself.
You said that the carb is new ?? If so.. why did you rebuild it ?? If you rebuilt the carb because the saw wouldn't run then the you may have other issues. Keep me posted..

Darryl

[barney]

Yea!! The saw is running now!

It turned out to be a weak spark, I think. I pulled the flywheel and the points where covered with a lot of oil. Cleaned, filed and reset points gap. When I checked the spark it was a robust blue bolt.The saw fired up after about 6 pulls. I let it warm up, flipped it both sides and the idle never changed. So, I think the crank seals are OK.

Before I pulled the flywheel I installed an ebay hdc-15 carb that I cleaned and pressure tested. Saw didn't fire, that's when I got into the flywheel. The coil checked out OK 

Once I get a guide plate and bar bolt&nut I can give it a workout.

Until next time thanks for all the help.

barney