Hard starting 088

[artwood]

I just replaced the piston and rings and am having a devil of a time starting my 088. It was starting and running fine until it lost compression. It will pop with the choke on and then I have to pull 20 times with half choke. Once it warms up I can't start it at all until it cools down for an hour. I have the carb set at one turn open on both H & L and idle set at 1.5.

Any suggestions? My wrist is really sore!!

 

[w8ye]

Open up the "L" another 1/2 turn to get it running and then adjust the needles properly.

 

[stihl038x2]

What "fried" the piston in the first place ?? Major air leak may be the culprit for both issues ? Carb rebuild time too??

Steve

 

[artwood]

Don't know what fried it. Just wouldn't start for lack of compression. I pulled the cylinder and there was no scoring or damage but a broken ring and a portion of the piston top edge was heavily scored.

I bought the saw used from someone in California about 8 yrs. ago. He was using it for milling. He said he either bought it or had the carb modified/bored out by Mark (can't remember the last name, but I've heard it on this site as a builder before).

 

[artwood]

I opened the L adjustment 1/2 turn and it did pop a little more, but still hard starting.
It sat for a couple years before repairing it. What would make it get too much air, gaskets drying out?

 

[a. palmer jr.]

Is the intake manifold boot ok?

 

[w8ye]

It definitely has a air leak.

Typical air leak locations are the intake boot, impulse line, and crankshaft seals.

 

[artwood]

Pressure testing

I took off the carb and inspected the boot and impulse hose and they appeared fine.
Maybe it's got a crankcase leak. I'm new to rebuilding saws and have two PS5100 's and a 346xp that I'd like to do piston & rings on. I should probably pressure test before rebuilding.

Will a Mightyvac MV8000 do a pressure as well as vacuum test?

 

[w8ye]

Yes, if you hook it up right.

 

[artwood]

I will go pick one up today. Hopefully, hooking it up right will be obvious?

 

[komatsuvarna]

Have you pulled the carb apart to see if its even getting fuel? Thats a long time to set,,, it could be dirty or partially blocked and not getting enough fuel. Id try that before I started tearing it back down again. After the 20 pulls will it run? Hows it run?

 

[artwood]

To be quite honest I don't know how to check if it's getting enough fuel. I'll pull the top off and see if the screens are plugged.
Once I got it running (wouldn't idle) and put it in the cut it ran strong.

 

[blsnelling]

FYI, the decomp is known to leak a little on these. So, if you find it isn't holding vacuum, check there first. If it's still not holding vacuum, pressurize the saw with 5-10 PSI and spray everything down with Windex. You'll have to remove the flywheel, clutch, and oil pump in order to check the crank seals.

 

[komatsuvarna]

To be quite honest I don't know how to check if it's getting enough fuel. I'll pull the top off and see if the screens are plugged.
Once I got it running (wouldn't idle) and put it in the cut it ran strong.

Did ya try idleing it up any??

 

[artwood]

I "rented" a Mityvac from Autozone. Pulled the muffler to plug the exhaust port and there was some wetness. Must've flooded it when trying to start it last night. So we know its getting fuel.
Checked the screen filter in the top of the carb and it was clean.
Plugged the intake and exhaust and hooked up to the impulse line.
Pumped it up to 10 in HG and it slowly leaked down to 0 in 6 min.

Should I pop off the flywheel and put a few drops of oil on the seal to see if it gets sucked in under vacuum?

Or should I try to pressurize it? How do I do it with the Mityvac? Or is it easier with low pressure from an air compressor?

 

[w8ye]

You saw passed the vacuum test . . .

On the Mighty Vac you have to unplug the hose and put it on the nipple on the other side of the pump.

Be careful about using an air compressor for you can blow the seals out of the saw.

Just use less than 10 pounds of air and shut off and watch for the pressure to hold for 1 minute.

 

[komatsuvarna]

Id be surprised if its an air leak, Thats what ever body starts hollering when they have saw problems. I think a dull chain might even be caused by an air leak .

So go clean the carb already!

Also, check the impulse and fuel lines, and fuel filter.

 

[a. palmer jr.]

Id be surprised if its an air leak, Thats what ever body starts hollering when they have saw problems. I think a dull chain might even be caused by an air leak .

So go clean the carb already!

Also, check the impulse and fuel lines, and fuel filter.

Sometimes its kinda hard to diagnose a problem 500 miles away!

 

[w8ye]

RA Dougan test the pressure integrity of a Stihl 032

He tests the crankcase, the impulse line, the gas line, the fuel filter, and the tank vent.

The chainsaw guy shop talk Stihl 032 chainsaw pressure, vacuum testing 10 20 - YouTube

 

[artwood]

Still having a hard time

starting it. I don't have a rebuild kit for the carb and really need to get it going to start a job with it. Took the carb apart and the diaphragms were okay, shot carb cleaner thru all orifices with jets out. Put it back together, got it started w/o the covers on. Stopped it put the covers on and can't get it started again. Seems to flood easy, is that the inlet jet?