075 trouble

[John Wagstaff]

Hi guys, Stripped down my 075 to have a look at the flywheel key, wasn't sheared as suspected. so needed to investigate further, I have invested in a Stihl test set (cost me UK£100) but I think it will prove well worth it, I have tested the ignition armature and the readings are as stated in the manual (1 ohm on primary and 8700 ohm on the secondary) so good to go, this is fitted with an electronic switching unit, so no testing needed as the manual stated when I did the spark test. So having cleaned everything and re-assembled her I tried to fire it up, and still have the same problem, that is when I engage the recoil starter it snatches back extremely violently. So guys, has anyone any ideas where to go from here??
I should also say that when I rebuilt the crank and bore assembly I did lightly coat all components with a light grade oil.

 

[67L36Driver]

Kick back (handle ripped from your fingers) is sort of normal for large displacement saws.
Use the compression release if you have one!
Try leaving the switch off, pull it over three times with the choke set. Turn the switch on, set it a half choke and pull it like you mean it.

A rich mixture kicks back less than a lean one.

 

[smokey7]

Kick back (handle ripped from your fingers) is sort of normal for large displacement saws.
Use the compression release if you have one!
Try leaving the switch off, pull it over three times with the choke set. Turn the switch on, set it a half choke and pull it like you mean it.

A rich mixture kicks back less than a lean one.

+1 on everything.

 

[Chainsaw Jim]

Would it be possible to give an explanation of all the symptoms of the saw before initial tear down? I'm not sure if you're trying to run it for the first time and you're surprised by the compression or if you've been running it and then one day it started acting up.

 

[John Wagstaff]

No not first time user, I have an 076aveq plus an 075ave both fully working and both we're mounted to my 48" mill. I acquired this 075ave under the guise of an 051ave and as a non runner. Whilst I could turn it over a could not get it passed tdc due to all the carbon at the top of the bore, hence the full strip down. Once I realised that it was an 075ave I want to use it instead of the 076 on the mill. However at the moment it won't run. Having cleaned all the internals and replaced parts as previously stated I expected it to fire and run. I have never had this running since I acquired it.

 

[BigOakAdot]

Does it have a decomp valve? My 076 super does not so it can really kick back at me when trying to start the saw. Sometimes I find it helps to pull it slow and let the piston turn over a couple times. Then pull slow and after you get the piston to go once, yank like hell. Seems to help me start mine.

Recently I flooded mine and this caused some serious compression grabs. Pulled the spark plug, and gave the rope a few tugs to get the extra gas out of there. That helped as well.

 

[alexcagle]

Might make sure bar oil isn't seeping into the crankcase and combustion chamber from leaking past the o-rings of the oiler gear. Been there done that.
It will make either hydraulic lock or some crazy compression.
But I'm sure if you have ran these 1111 series saws for a while, it's already happened to you.