088 full of treacle?

[BlackDogScot]

Hi all, my 088 runs beautifully. When I can start it!!! Sometimes it is absurdly hard to pull, and the (new) decomp valve pops out mid pull which, as a real lightweight, I just love. Other times it spins over just like you'd hope for, firing up easy.

Often it'll fire after a couple of easy pulls from cold, on choke. Then on half throttle, seconds later, it feels like the starter is full of treacle and it starts the decomp-valve-popping-early game.

I've had this one for 20 odd years, in regular but not frequent use. Mostly cleaving big logs for milling on a Mizer. Recently I switchd to top grade fuel (on Angus Chainsaw's advice) which helps.

Anyone got any idea what's going on here? Would be mighty grateful for help. I hate to think I'm getting too old n weak!

[gobbypunk]

Hi my 880 can be a real bitch to start and has been from new if it starts first couple of pulls it will be fine all day but if its a bitch to start then its like it all day

[Mark_Skyland]

I would check to see if fuel is leaking into the cylinder causing a partial hydraulic lock, especially if the decompression button is popping out. Pull the spark plug and turn the machine upside turn to see if fuel comes out of the spark plug hole when pulling it over, best to make sure the ignition is switched off though!

 

Big saws that rarely get used can gum the carb up, the needle valve may leak causing difficult starting or the metering diaphragm can stiffen up causing the same issue.

 

 

 

 

[spudulike]

Often, when a saw is left for a while, the fuel coating the bore can evaporate leaving the oil that then creates a decent load of compression. Many MS200s with worn pistons have caught me out for this reason but in larger saws, it makes them difficult to pull over.

[green heart]

Yep, I've also had very similar experiences, with our old 880, on those infrequent occasions it's needed. 

 

It seems to be easier/prefer drop-starting, when warm... not a practice I'm particularly keen on tho !

 

[BlackDogScot]

Thanks all, really helpful.

Gobby I'm glad I'm not alone! Yes always was fine once started first thing. As Green Heart says, a drop start is best (with two pairs of gloves against the kick-back!), but recently mine has been misbehaving even once warmed.

Mark S I'm going to try this, makes a lot of sense. Now you mention it, it's had no big carb service ever, probably  But forgive my ignorance: if the ignition is switched off, doesnt this mean fuel will also be off. Could I not just whip the plug out, would that reduce risk?

Spudulike, do you reckon this deposit 'sticks around', or would you expect it to burn away once the beast is running for a few mins? 

Thanks again

[BlackDogScot]

Mark S, when I say 'whip the plug out', I mean out of the lead...!

Cheers

[Muddy42]

I have an 088, so I understand how you feel, it makes my shoulder hurt just thinking about it. I sometimes find starting my 088 is a two man job. A squirt of fuel on the air filter speeds things up too.

 

As above I wonder if it could benefit from a carb kit which would refresh the diaphrams ensuring 1) fuel was pumping correctly and wasn't also flooding the cylinder.  Decomps can benefit from a clean and wire brushing once in a while.

 

 

[openspaceman]

13 hours ago, green heart said:

Yep, I've also had very similar experiences, with our old 880, on those infrequent occasions it's needed. 

 

It seems to be easier/prefer drop-starting, when warm... not a practice I'm particularly keen on tho !

 

the trick to drop starting a saw with lots of compression is to gently ease it over tdc before the attempt.

 

[Muddy42]

or get someone else to slog away at it for 10 minutes then take over when its just about to fire!