Lawn Boy Experiment Gone Bad

[Cmarti]

Took the LB out of storage, and filled it with Stihl ultra 50:1.
Started great ran quiet with no smoke. I notice a little nock at 10 minutes. After 20 minutes the mower has lost power and is surging. I check the air filter and plug, OK. Drain the fuel, and add the TCW3 at 32:1. After 30 seconds, she is roaring again. I just can't believe the oil or ratio made that big a difference. I am probably stupid enough

to try it again.

I really wanted to run one 2 cycle, and I have fallen in love with the Stihl Synthetic in my saws, trimmers and blowers. I guess LB recommends a TCW3 for a reason, or that ratio was just not right for the Duraforce engine. I ran TCW3 Valvoline in everything for years with no problem, but worried about blowing up a saw, and hated mixing 4 *&^%&^$# ratios.

 

[Johnny]

It's not the oil, it's the ratio. Lawn Boy 2-cycle mowers love 32:1 mix. Use the Stihl oil just a richer mix for the Lawn Boy.

 

[Nyquist]

My Dad has something similar to what you do. He dropped his ratio to 40:1 to curb some smoke and hasn't had any noticeable problems in spring. In summer when it's warmer he goes back to 32:1.

 

[Cmarti]

Originally Posted By: Johnny
It's not the oil, it's the ratio. Lawn Boy 2-cycle mowers love 32:1 mix. Use the Stihl oil just a richer mix for the Lawn Boy.


I know... how big a deal is it to mix another can of fuel? I am just the type that has to experiment.....I am still curious, as so many folks claim it is the oil not the engine that determines ratio. With Lawn Boys is it tolerances, and a heavier mix needed for compression? I guess I can just accept having that 32:1 can around!

 

[Steve S]

The lawnboy engine is a low rpm engine. The chainsaw is a high rpm engine . So the difference in oil .There are universal 2 cycle engine oils but I am not expert on the oils. Also the oil ratio may change the air feul ratio

 

[Tom_T]

If you're comfortable running that 50:1 ratio, I really would try it again. Surging is usually caused by a lean air/fuel mixture, knocking as well. Could have been a sticking float valve (closed) or some trash/gum in the carb jets. Maybe the 50:1 mix was old or had a little water in it? I'd run a little Seafoam (my personal choice) through it and give it another go.