Skilsaw won't start

[choptime]

I've got one of these. For the darnedest I cant get it to start. Originally, when I got it, it WOULD start but it would lean as fuel was used up.
Upon rebuilding the carb, I found the diaphragm that pumps fuel was removed, so It was just pulling fuel via vacuum. I figure that is why it leaned out as fuel ran out - "it had to suck harder".
*SO*
after rebuilding the carb, It is not pulling fuel. I tried manually pumping via a vacuum\no vacuum at the carb itself and fuel moves up the hose.
It will run for a sec if I pour fuel down the carb....
Lastly, I check for engine seals and no leaks.
As a result, it makes me wonder- how do I test if the lower chamber is producing pressure to make the pump work?!?!?!?

TIA.

 

[Bob Hedgecutter]

These things came in about every colour of the rainbow and near every makers name- but they are all Frontier F35's at the end of the day.
They impulse through the intake block- no separate line- so make sure the impulse channel is lined up with the holes in the gaskets and the channel is clear. Better yet, find, buy or make new gaskets as any leakage below the carb will not help with what you are experiencing.
Some go to the effort of flat sanding each mating face of the impulse block to ensure flatness.

 

[choptime]

These things came in about every colour of the rainbow and near every makers name- but they are all Frontier F35's at the end of the day.
They impulse through the intake block- no separate line- so make sure the impulse channel is lined up with the holes in the gaskets and the channel is clear. Better yet, find, buy or make new gaskets as any leakage below the carb will not help with what you are experiencing.
Some go to the effort of flat sanding each mating face of the impulse block to ensure flatness.

I already tried a new gasket and confirmed it is not sucking air. I rebuilt the carb and even tried getting another carb(also rebuilt- 1 Tillotson, 1 Walbro) and it still won't run. I even took a vacuum cleaner and "pulsed" the carb to test if the carb pumps fuel and it does.
This is why I inquire about the pulsing\pump.

So I guess make a tool to see if there is any pulse to pump the fuel????

I'm starting to wonder about these small saws as I got another one a while back(in my other post). I have other bigger saws like a homelite C35, Mac 10-10, and more and never have these problems...

 

[Bob Hedgecutter]

Fuel is not getting from tank to carb then- new fuel lines and in tank filter.

 

[choptime]

Fuel is not getting from tank to carb then- new fuel lines and in tank filter.

I replaced it with a clear hose so I can confirm it - there IS fuel in the hose.

 

[Bob Hedgecutter]

Pressure and vacuum test the lines, the carb and the saw engine.
New correct spark plug.
My guess is, if all the ducks are in a row fuel delivery wise- you have a massive air leak at the crank seals or the like and saw is not building the impulse needed to deliver pulse to the carb.

 

[choptime]

Pressure and vacuum test the lines, the carb and the saw engine.
New correct spark plug.
My guess is, if all the ducks are in a row fuel delivery wise- you have a massive air leak at the crank seals or the like and saw is not building the impulse needed to deliver pulse to the carb.

I already did test for a leak but I didn't test it with air pressure\vacuum(and found no leaks). I guess I will need to or else save the time and just replace the seals.

 

[Bob Hedgecutter]

So how do you leak test without air pressure or vacuum?
There is always a reason old saws are shelved and then sold cheap- seldom do you find a free lunch.

 

[choptime]

So how do you leak test without air pressure or vacuum?
There is always a reason old saws are shelved and then sold cheap- seldom do you find a free lunch.

I didn't test that as as I said - i pour some gas in and it runs.
Also as I said, It actually ran and I actually chopped some wood, but It would lean out.

Something about these small saws as I am 0 for 2 but the other bigger saws I got all run after rebuilding the carb.

 

[Bob Hedgecutter]

Well, it sounds like an air leak- probably main crank seals- or the crankcase pressure oil pump.
If it ran and then leaned out- ie: started to climb in revs alarmingly- its sucking excess air from somewhere.
This kind of condition will tear up a piston fairly quickly.

One way of ruling out low compression is to take out the spark plug and pour a teaspoon or so of oil on top of the piston, swill it around and replace the dry spark plug- try to start the saw as per a normal cold start.

 

[choptime]

One way of ruling out low compression is to take out the spark plug and pour a teaspoon or so of oil on top of the piston, swill it around and replace the dry spark plug- try to start the saw as per a normal cold start.

Just for kicks, I poured gas down the carb the other day, and it ran.... again. I have done that several times as mentioned before. Oh well, I'll fiddle with it now and then if I'm bored. maybe someday find why it isn't getting fuel.

 

[choptime]

*UPDATE*

I was fiddling with another saw that for the life of me, wouldn't start on its own. for Doo doo and giggles, I pressed the diaphragm and it started so I got to thinking... the diaphragm may not be going down far enough to lift the needle. Bending the "arm"?!?! so that the diaphragm lifted the needle and it runs now.

TADA!!! it runs!! When it rains it pours as I also got the Poulan to run.