Stihl 076av rebuild

[Brewz]

hast makes waste.

I know.

I did everything slowly and properly and was rushing to get it to run cause we were going out for the afternoon.

Lesson learnt

It was dry and squeaked so needed pulling apart anyway

 

[Brewz]

It just jumped the spring so I took the opportunity to clean it out and fit up a new rope.
Works perfect now.

It is a monstrous beast
Sounds great!

Video of its first run and cut is loading.

Here it is next to an 064 for comparison.

 

[Brewz]

The only bar i had to fit it is a dodgy old hard nose thing that was on the 090 I am building.
I ran it with the chain that came with the bar that felt fairly sharp but I think needs the rakers taken down.
It also needs a good tuning but if I spend any amount of time tuning this thing in my garage someone will ring the cops.

 

[Brewz]

Going to give it a run and tune tomorrow

By the way, that timber is dry and hard as nails.
404 full chisel chain running a 7 pin

 

[johnny5ny]

Very cool thread and awesome that you were able to see it through to a running saw!
Congrats! I dig it

 

[Brewz]

Thanks!

It was a LOT of work.

Here is a bit of a comparison of before and after

 

[Brewz]

Oh, and the little but effective muffler mod I did.

Just taking out the flats between the openings easily doubled the size of the outlet over all.

 

[jake wells]

just need a large bar and a agressive chain now.

 

[Brewz]

I gave it a good run today.

It ran good then suddenly just went full revs in its own.

I flicked the off switch and it kept running so I choked it to stop it running.

Checked the carb and throttle and it was fine so I fired it back up.
It idled fine for a few seconds then wound its self up to max revs again.

Once again, stop switch did nothing.

Might I have got it a bit hot and made it diesel?

 

[jake wells]

I gave it a good run today.

It ran good then suddenly just went full revs in its own.

I flicked the off switch and it kept running so I choked it to stop it running.

Checked the carb and throttle and it was fine so I fired it back up.
It idled fine for a few seconds then wound its self up to max revs again.

Once again, stop switch did nothing.

Might I have got it a bit hot and made it diesel?

try higher octane and tune it fatter.

 

[Brewz]

Ok
Was running it on 91 mixed 40:1 with benol.
I had to pack up and head to work for a breakdown

Will check nothing came loose and give it a start when I get home, see if it runs ok cold

 

[Iron.and.bark]

You used new fuel filter and crank seals?

 

[Brewz]

Oh yeah.

New everything

So is that what they do when they diesel?

It sure was an experience holding a saw that size going full stick and refusing to shut off

 

[jake wells]

i call it run-on when it happens in a 4 cycle but the symtoms is usually high timing or excess carbon deposits causing hot spots in the engine.
never have seen it happen on 2 cycle engines only 4 cycle 6 or 8 cyl car engines.
mixture to lean or your timing is to far advanced???

 

[Chainsaw Jim]

Case bolts could have rattled loose. Everything rattles loose within a couple cuts on these things unless you use red loctite on clean dry threads.

I've spent most of the evening cleaning all the threads on mine and tapping some of the holes with buggered threads to the larger 6mm screws on my 075 before reassembly. That and a fresh 1.2oz bottle of red loctite and this thing might just hold together.

 

[VinceGU05]

shes a fat bottomed girl alright!!
check the plug color and temp range. it may have turned into a glow plug, but you got some good suggestions above to look into. GL!

 

[Brewz]

Just kicked it up and its fine.

I think it was a case of heat causing it to diesel

 

[Chainsaw Jim]

would the 041 muffler work it is just a empty can with no baffles.

The 041 muffler is a smaller version of the 076. The 051 muffler is the same size but the exhaust opening inside the flange is almost half the size of the 076 so there's no reason to consider it.
A person basically needs to modify the stock muffler or have a pipe built.

 

[Brewz]

I think I know what happened.
The timber I was cutting is hard as nails, unsplitable on a 22t hydraulic splitter, but light and does something odd.
When I noodle the round quarters, it clamps in on the bar and chain, making cutting a difficult task.

The o76 is running a very wide hard nose bar and the wood was clamping in and jamming the chain on the top of the bar, causing the clutch to slip from the jamming effect.

I know this because the cuts I made with it before it went into its possessed, destroy the world diesel mode had smoke coming from the clutch cover which smelt of burning bar oil.

I was cutting and it started cutting slowly so I gave the aux oiler a couple pumps.
Then the smoke started coming out.

The wood was clamping and jamming the top return chain.

I probably pushed it harder than I should have due to the smoke, but the video I took looks way worse than it looked while I was cutting. I just figured the extra oil i pumped hit the hot clutch drum and smoked.

I think the heat from the struggle with the clamping wood rounds soaked in somewhere and caused the 12000+ rpm running with no spark

The video is a bit embarrassing as the smoke didnt look that bad from the top but I will upload it and post it up for a laugh.

nasty timber to stall a 111cc saw at under 20" thick

Geez it burns hot though!

 

[Brewz]

There is not much more to say than this