Hard Starting

[swines]

I've been using 2-cyle motors since the mid-1960's. I've come to believe that they're like children - all of them are different and some of them are extremely finicky.

I learn what it takes to get each motor started. The blower/vac takes 5 pumps of the primer bulb unless it's completely warm. The MS192 saw takes three pumps of the primer bulb (more and it floods, less and it's not enough), the choke set to full choke and two pulls - then the choke at 1/2 choke for one pull and it starts. The MS 261 after sitting for several weeks takes two pulls at full choke, then two at half choke - and it starts.

You see what I mean...none of them start the same way. I've found that my Stihl equipment absolutely hates gas with ethanol even if you put ethanol treatment in the gas and stabilizer.

I've switched to 100 octane unleaded with no ethanol. All of the equipment works better and starts easier.

Unless there is a mechanical problem (blocked passage, stiff diaphragm, leaky fuel line, etc.) - I would check the sparkplug and make sure it's either clean or new; change to ethanol-free 92+ octane unleaded fuel; learn the exact starting sequence that each tool seems to like.

 

[swines]

Stihl has the pump primer bulbs on the weed eaters and pole saws. Why not on the chain saws?

They do on the "Homeowner" and "Farm and Ranch" saws. The "Professional" saws do not have the primer bulb.

 

[mjcountrybumpkin]

Compression seems low to me. I am thinking off the top of my head it should be at least 160.

 

[2458n]

You are Stuck with the hard starting as the diaphragm has gotten hard from ethanol. Should try to start on the first pull with choke full on. If it does not go to partial choke and it should fire and run. The either should be reserved for old Cat engines. When you have the carb apart to replace the diaphragm check the fuel hose also. Give the carb time to soak in cleaner. If you do this they will be ready to run if you dump the fuel when you are done.

 

[smstonypoint]

They do on the "Homeowner" and "Farm and Ranch" saws. The "Professional" saws do not have the primer bulb.

Huh? My MS170 doesn't have a primer bulb.

Steve

 

[Egon]

Compression seems low to me. I am thinking off the top of my head it should be at least 160.

I'm not sure what the value for good compression is but it surely sounds like a compression issue.

 

[Patrickdozer]

I would definitely use ethanol blocker/additive or find non ethanol fuel. Had similar problem with my saw this past year. I figured compression was too low after using for couple years. Started to use ethanol additive and saw has worked pretty good ever since. A repair shop told me to use premixed, only problem is its expensive and im cheap at times..

 

[davesl708]

It has always started hard even before the muff mod. If it sits a week or so it takes 15 pulls. I cut a lot of wood and rotate the saws a little but the 034 is usually sitting at my cabin unused most of the time.. I mostly use a 039 or 044. They start right up. This little 034 hates me. Anyone want to buy it? lol..

I did fail to mention I use pure gas in all my equipment.

 

[mjcountrybumpkin]

I had an older saw that had a very similar problem, but being as it was 70 cc I usually ran out of juice before it would start.
Originally thought it was a fuel problem also. Checked compression at 100 lbs. thought that was good. Then I looked it up online and it was supost to be around 185 lbs.
The saw had a stuck ring,pulled the jug and remove ring and repaired ( with the file I sharpen the blade with). Re assembled it and got compression up to 165.
Starts like a new one. Second pull every time.

 

[yomax4]

Interesting. I did switch to non ethanol fuel a while back. I may as well throw a kit in the carb before I throw a new jug and rings at it. I'm shocked at how inexpensive the cylinder and piston kits are. Even complete engines are reasonable. I'll do another comp check 1st. Stihl says 160 is new.
Thanks.