I have a chain saw I inherited from my uncle. I had to replace the primer ball and the fuel lines, as well as a diaphragm from the carb. It runs just fine for around 30 seconds to a minute, then dies like I shut it off, but I can see that it still has spark with an inline tester, and the primer bulb is still full of fuel. I am at a loss, and am looking for ideas how to get it to stay running. Pumping the primer bulb doesn't help either.

 

Sounds like (maybe) bad fuel over time has oxidized and gummed carb jets orifices Have you tried cleaning the carb e.g. how far did you take the carb down

 

Carb looked clean. I got it going, mostly. Found that the fuel line that was actually the main supply line independent of the primer line was broken. Had to figure out where it went, then got it worked through. Ended up doing the same with the primer line as well. Still had the issue, so I had found some had to run the mixture screws in to clear the passage, then back them out. I suspect I need to turn the high speed screw a bit more, as it wavers at full throttle now.

 

Good deal. What are you running for the mix? I like the Opti - it's good stuff and suitable for all 2 cycle equipment at 70-1 or so.

 

This round I put Lucas in, I think. I started monkeying with it a month or so ago, and been a couple weeks just getting parts in. I only get a chance to get the parts picked up on weekends, so I would wait all week to get them. First was a primer bulb, then the carb kit. I know it was a synthetic that claimed to be good for multiple mix ratios. I mixed the gas about a month ago now...

 

Supposedly Opti isn't a synthetic? I dunno. Works good, haven't had any problems. The lawn care folks seem to like it too from reading those forums.

 

I didn't grab it so much for being synth, just was available and reasonably priced.

 

Well there's that. I bought a gazillion of those little packets that make up a gallon from eBay.

 

Ethanol took out all the fuel lines on my mid 90s Poulan saw, The replacement lines are able to handle it. Its tough to replace some of the lines. I put my car in my vat while I found replacement parts. It runs great now.

 

That's a pretty good sized vat, sounds like?

 

Carb i meant. I need to proof read my post

 

I run the Lucas in most of my stuff, from chainsaws to dirtbikes to sleds and even my Lawn Boy.
Make sure the spark arrestor isn't gummed or plugged, it's the little screen in the muffler.
A popular trick from the Lawn Boy group is to bake the muffler on the grill for a while to dry out all the gum so it can be shaken out.

 

What's the mix ratio for the Lucas oil?

 

It's multi-ratio, I run it at 50:1 usually.

Sent from my C771 using IB AutoGroup

 

Ok. Opti guys are running 70-1, some even higher. I like it because it doesn't smoke. The packets are 70-1 so that's easiest to figure. It's nice not to have three or four different mixes. Use it for lawnmower, sno-blower, weedwacker, etc.