What causes dying on sustained load?

[Canyon Angler]

My little tree saw (Dolmar 3410TH with reed box) seems to run fine for short cuts -- plenty of power, good throttle response, seems to run fine -- but if I put a sustained load on it, for example, if I try to buck up a 6" log, it dies as if it's starving for fuel. I can sometimes keep it going by "pumping" the throttle trigger, but usually not.

Is this commonly a symptom of a particular problem? What would you folks look at first? Fuel filter...?

Sometimes the reed box gets "loose" and it exhibits symptoms of a borderline air leak where you can't fatten it up enough to get the WOT RPMs down and the proper flutter/burble sound...I'll check that. Anything else?

 

[HarleyT]

Look at the carb, especially under the passage under the needle. It may be partially blocked, and causing it to starve when under a load.

 

[OM617YOTA]

Plugged tank vent?

 

[KASH]

Open the high needle
Kash

 

[SEAM]

Also check the fuel filter for signs of clogging... any restriction in the fuel supply route can cause leaning out at high rpms - as can a tiny air leak (fuel line, carb gaskets, etc.).

 

[Canyon Angler]

Thanks for the replies. Before I go tearing into a carb, I always try a good dose of Sea Foam -- especially on equipment that's being re-commissioned in the spring after the winter layup -- and even though this saw was run dry the last time I used it, it looks like Sea Foam might have saved my bacon again! Fingers crossed...

 

[Canyon Angler]

Open the high needle

As Scotty used to say on Star Trek, "I'm giving it all she's got, Captain!"
(The H doesn't open any farther than it's already opened...or I should say, it doesn't give any moar fuel than it's already giving...)

 

[dmb2613]

sea foam has never fixed anything for me , nor do I expect it to

 

[Piotr Pakula]

Recently, I had two chainsaw, both had a clogged carburetor and one had no strainer. They lit well and did not go out at idle

 

[Canyon Angler]

sea foam has never fixed anything for me , nor do I expect it to

I don't normally buy Snake Oil, but Sea Foam has saved me from having to clean out 2T carburetors on boats, saws and trimmers half a dozen times or so, so far.

Before the Sea Foam treatment, the only way you could keep them running is by choking the crap out of them. After Sea Foam -- back to normal. YMMV.

 

[HarleyT]

It cured my arthritis too.


Not so much on my peyronie's disease....

I still pull to the right.

 

[holeycow]

Sea foam is a powerful solvent and shouldn't really be used in 2 strokes, imo.

it does work to clean fuel systems tho it's better to clean mechanically than to rely on it as a do-all cure.

the naysayers on these gunks haven't used them. Or have used them when things are beyond their capabilities as a cleaner.

The saw in question has classic symptoms of fuel starvation.

 

[Canyon Angler]

Not so much on my peyronie's disease....

I still pull to the right.

Pee-On-Yer-Knee's Disease? Wha?

 

[RedneckChainsawRepair]

Seen this with old diaphragms that has gotten stiff. Run out in cut. Take it out start right back up and do it again. New kit and all good.

Something easy to check and replace.

 

[Canyon Angler]

Seen this with old diaphragms that has gotten stiff. Run out in cut. Take it out start right back up and do it again. New kit and all good.

Something easy to check and replace.

Thanks. I hope that's not it...seems like I just rebuilt the carb on that saw like 2 freakin years ago.

 

[HarleyT]

peyronie's disease

Good Lord!!!
Don't do a Bing image search on this!!!
Trust me!!

 

[HarleyT]

I was just trying to find a pic of the goofy guy holding a bent chili pepper.........

 

[Canyon Angler]

I was just trying to find a pic of the goofy guy holding a bent chili pepper.........

Suuuuuuuuuuuuure you were. And I was just tryin' to help that lamb climb over the fence, too!

When people told Harley to "go get bent" -- he listened!

 

[Jasonrkba]

Hows the plug look?

 

[Volund]

Lack of fuel.