I have used Marvel Mystery Oil and Seafoam ( separately, not together) ...they both seem to have some benefit as engine cleaners...I have seen and heard of rough running engines start to run better after using them...Seafoam also serves as a stabilizers ( according to their written information)

 

I always add Seafoam to my fuel. Mainly as a stabilizer, but I haven’t had to clean any carbs since. It’s been a few years.

 

I use Seafoam as both a cleaner and stabilizer and it works, I mix up my own home brew Seafoam
Also use Marvel mystery oil from time to time

 

Project Farm has a series of videos on YouTube. I always find them informative, but wasn't really interested enough in the answer to actually watch them all.

I have used and had a good experience with Seafoam. If I had a real need now, I would watch the various videos that compare Seafoam, MMO, and Techron.

 

Techron, I think that was one I heard was ok.

 

I find that seafoam has always worked well in the fuel and marvel mystery oil works well in oil.

 

I usually use either SeaFoam or STA-BIL. Both work great!

 

I use a 50/50 mix of Seafoam and Sta-Bil did my Kolher engine well for 25 years, no issue and is now running in my Kawizaki for 5 years.

 

Techron - among the best fuel system cleaners if not the best and the stuff supposedly doesn't leave any deposits.
Suppose though it's like all - works best when used on a regular basis.

 

A youtuber named taryl fixes all made a entire series about this kind of product, alot of product suprinsigly failed after about a year, i suggest you go wacth it. I use Sta-Bil, and never had an issue so far, exept with my mower,but it not the stabil, its something else,

 

I use Polaris carbon clean in my 2 strokes and I'm sure it would work in 4 strokes even better! if it can deal with the carbon buildup on powervalves in a 2 stroke there likely isn't anything harder to clean!

 

I try to stay away from anything polaris, we bought a polaris atv, it lasted 2 weeks before the engine blew up, we changed the oil when we got it, oil was old, but no metal, no weird sound from engine, we change the oil, put a brand new polaris oil filter, and then 2 weeks later, engine blew up, it started knocking badly and seized up. We sold it for parts, and bought a yamaha atv.

 

I have had good luck with Optimizer but not sure if it is still available. I used to get complaints about Briggs and Stratton fuel stabilizer, it left a grey coating on fuel system parts that was hard to remove. It was actually a corrosion inhibitor but dealers didn't like it.

 

Really like marvel mystery oil,use it for many things,good rust preventer too,

 

Taryl tested storage products. Not cleaners… I’ve had success with gumout fuel injection and carburetor cleaner. If an engine runs at least a little. It will get it running better. I’ve done it multiple times rather than pull and clean a carb. Not perfect but in a pinch

 

Thanks for all the great input and thoughts.

Going to try Techron in the 757 Z turn, carbureted, and in the X585, injected, and see how it does.
Not sure if I'll see any actual difference but time will tell!
Both also run high octane non-ethanol fuel, as do all my small gas engines.

 

FYI on these additives:
Fuel additive SDS ingredients

Do you really want to put that stuff in your fuel?

 

Fuel System Maintenance: Any engine that doesn't run or sound as it should will get a dose of Seafoam in the fuel. It's my GO-TO for that problem.

Fuel stabilizer: I used Seafoam for a few years and after having some problems with winter storage of my '84 F250HD I switched to using Stabil. No problems ever after. I never put any fuel in any storage container, even though I use only NO-E gas in small engines, without using Stabil. My older engines also get some Marvel Mystery Oil added to the can.

 

I use the Lucas carb & injector. $10 +- for a quart.
In everything gas. Car, trucks, swisher, tiller, chainsaws........

 

SeaFoam. I mix it in my cans when I fill then so my small machines are always treated. I give seasonal equipment a little sip od MMO before storage. Never had a problem starting after sitting for months