Jonsered 630 Chainsaw Problems

[JohnD-Gman]

I have a 630 that has been sitting on the shelf for years until recently. I pulled it off and put in a carb kit and replaced the jelled fuel lines. The saw has good compression 175-180 psi by pulling the rope. The saw will generally start on about the 4-5 pull and run good for a while, then after it gets hot it will go dead when I let off the throttle. It is very hard to restart and hard to pull. I have been using a packet of 1.8 oz of Opti-Blend Oil to a gallon of gas. The dealer says this oil will run all 2 cycle engines from 16:1 to 50:1 requirements. What is my problem?

 

[Crofter]

Could your low speeed mixture be too rich. What would be a workable setting when the saw is cold would make it stall when hot.
Frank

 

[buckwheat]

coil or coil gap?

 

[HUSKYMAN]

My math shows that to be almost a 75:1 mixture. Better pull the muffler and look for piston scoring. Hopefully you dont have to visit your dealer

 

[cbfarmall]

Funny that Opti-Blend should come up here. My local dealer successfully passed that stuff off to me, claiming that the Opti LUBRICANT was far superior to regular 2-cycle OIL. Used it in my weedeater which is still fine, but when I worked out the ratio I decided that it belonged in my van and not in my 2-cycles.

My friend used to run my 045 up to when they used this Opti-Blend stuff, passed off by that same dealer, and toasted the piston. He gave the saw to me to fix. Had loose case screws and a possible air leak but I can't help but wonder about that Opti stuff.

Now I use Maxima at 32:1 in everything including that weedeater (which is running better than ever.)

Chris B.

 

[Methoss084]

I've been running 40:1 (Stihl mix) in my 630 for the last couple of years with no problems. I heard about plenty of people getting suckered into buying that mix in a packet. But like you said, most of the saws had other major problems like leaking crank seals and bad air filters that seemed to do them in. But I to wonder how great that stuff actually is.

 

[Tony Snyder]

Several years ago I carried some oil with Opti in the name, I'm not sure now what the rest of the name was. We had three or four locked up or scored saws from it. I also had some stuff with the Granberg name on it (synthetic) that we suspected was the cause of similar failures. I have stayed away from synthetics with 100 to 1 ratio claims ever since.