Cleaning fuel system; premium gas or cleaner additive?

[zuren]

I got my dad's Jonsered 70E running after changing out the SEM unit. I had planned a more extensive cleaning and teardown, but I have run out of time. I have done some searches and found mixed info scattered about.

What would be best for a 25 yr. old saw that has been sitting for the last 3 years to clean things up internally:

1. Run a tank of premium gas through it
2. Fill with fresh regular grade gas and add a tablespoon or two of Gumout fuel system cleaner
3. Run premium fuel AND some fuel system cleaner
4. Leave well enough alone, don't use premium or any fuel system cleaner.

Like I said, the saw is 25 years old with light to moderate use over that time and has been sitting (with gas in the tank) for the past 3 years. The manual does say to use regular grade gas, but I only plan to run 1 tank of the good stuff, IF that is the best option.

What do you guys do to keep things clean and flowing? Any input welcome!

 

[scottr]

Fuel system cleaner

Zuren , I've used Mercury Marine fuel system cleaner for about 17 years . It's mixed 1 ounce to 4 gallons of gas .

 

[zuren]

Any other comments?

 

[Lakeside53]

Don't run it. Clean out the entire fuel system with naptha/white spirit (colman lantern fluid). Same with carb (just pop the end covers and soak it over night - should clean up). Change fuel filter and make sure the carb inlet filter is clear. If you feel comfortable, this would be a great time to rebuild the carb - it's only a few minutes more.

 

[Lakeside53]

Don't run it. Clean out the entire fuel system with naptha/white spirit (colman lantern fluid). Same with carb (just pop the end covers and soak it over night - should clean up). Change fuel filter and make sure the carb inlet filter is clear. If you feel comfortable, this would be a great time to rebuild the carb - it's only a few minutes more.

...and it doen't matter if you use regular, mid or premium. Fresh gas is fresh gas, but don't use any gas with alcohol in it (like Arco and the other low tier brands etc). I recommend mid grade Chevron only...

 

[zuren]

Don't run it. Clean out the entire fuel system with naptha/white spirit (colman lantern fluid). Same with carb (just pop the end covers and soak it over night - should clean up). Change fuel filter and make sure the carb inlet filter is clear. If you feel comfortable, this would be a great time to rebuild the carb - it's only a few minutes more.

I did a little more searching and found threads that started talking about this, but began to get off topic. I'll just switch the gas out and see where everything stands. A carb rebuild may be in order in a year or 2 since I just got the thing back together.

 

[GASoline71]

zuren, you may want to look into replacing the fuel line as well as the filter. It's just cheap insurance, and quick and easy to make sure it isn't gummed or up, or rotted as well.

Gary

 

[zuren]

zuren, you may want to look into replacing the fuel line as well as the filter. It's just cheap insurance, and quick and easy to make sure it isn't gummed or up, or rotted as well.

Gary

I'll check them when I empty out the tank. When I took all the records out of my dad's file, I found receipts for all new fuel line, filter, etc. around the time that this thing stopped working. I'm betting he thought it was a fuel feed problem that then ended up being the SEM unit. So they could be gummed up a little, but probably not rotted.