Mechanic In A Bottle, TRULY Helped my old Harley!

[SOUNDMAN5000]

I'll admit, I love a good Snake Oil... but only a few do I use and trust.

My old 1997 Harley I purchased new in 97 started to show it was time for a carb rebuild 4-5 years ago. I now own newer bikes so my old girl gets neglected and seldom ridden as I been putting up with the hard starts and not running so good util I had time to do a carb rebuild, when you have another NEW Harley it can be EZ to put things like a carb rebuild off... That said putting a rebuild off turned into my old bike sitting unstarted 2+ years ( It did have a full tank of ethanol free gas and a mix of Sta-bil and Marvel Mystery Oil when I parked it ) but I knew 2+ years ago it was past time for a carb rebuild ( S&S Super E carb installed about 27+ years ago with no re-builds ).

I decided to get the old girl cleaned up and started expecting to rebuild the carb but after seeing some positive YouTubes and reading the bottle I thought what do I have to loose knowing its time for a rebuild, knowing the bike has sat 2 years why not try mechanic in a bottle, If nothing else its made in Conway SC and thats in my back yard so why not give it a try?

After reading some reviews / videos for mechanic in a bottle the directions are not clear or some folks ( perhaps I ) are confused, some say drain the gas and allow MIB to soak but the directions say don't drain gas, use 2 OZ per gallon IF your engine wont start and use 1 OZ per gallon IF it does start. Start or not run the engine or turn it over to get the mix in the carb and let sit a minimum of 4 hours.

I did drain my Harley 5 gallon tank as I had no plans to use 2+ year old gas/ Sta-bil or not as I looked and it was cloudy and 2 years IMO is the limit for Sta-bil so I drain the gas and re-fill with about 1+ gallon fresh gas and 2+ oz mechanic in a bottle.

I drive it around 15 miles to work that MIB into the carb as suggested and its not running good at all!
Was very hard to start but I got its started, bogged down on acceleration, very limited power feeling but I got things up to temp then parked the bike ( that mix now sitting in the carb ) and took me a good week to get back to it.

I drained this gas again and started fresh with a new full tank of Ethanol free 93 and my normal mix of Sta-bil and Marvel Mystery oil, I changed all my fluids ( oil, primary and transmission) as well and did a well deserved deep clean wash, a paint correction and proper detail and wax, Got things put back together and took the old girl out for an extended ride today!

I'm totally BLOWN AWAY! This mechanic in a bottle stuff worked!
My bike started like it has not started in many years, smooth idling, no bogging on accelerating! WoW My bike is back on the road!

I'm sure my old carb could still use a re-build, I have the kit but now thats a winter project that can hold off till winter!

I know, I know Snake oil but when you got nothing to loose but the price of the bottle of snake oil why not?
It did work for me!

I watch and enjoy that small engine repair Youtuber Chickanic, She likes the ethanol shield ( made by the MIB folks ) and she has mentioned mechanic in a bottle as well so after watching her videos I thought I should at least try it!
Glad I did...

 

[doitmyself]

I know, I know Snake oil but when you got nothing to loose but the price of the bottle of snake oil why not?
It did work for me!

Recommended by someone on the Lawnsite forum as a last resort, I tried the Mechanic in a Bottle on an Exmark zero turn Kawasaki engine that I thought had a carb problem (plugged jet?). I even had a carb rebuild kit already on hand. After a week or so running the "snake oil", the problem went away. Coincidence?? I can only guess. Maybe a great mystery?? - Hey, some religions rely on this explanation, lol.

 

[Kira]

Take that 30 year old bike and RIDE IT.
How are its tires? Is that belt or chain?
Please post model and details.

 

[spasm3]

Here is the SDS with most of whats in it.

https://b3cfuel.com/wp-content/uploads/2025/08/2025-Mechanic-in-a-Bottle-US-Only-SDS.pdf

 

[SOUNDMAN5000]

Take that 30 year old bike and RIDE IT.
How are its tires? Is that belt or chain?
Please post model and details.

She is a 1997 Harley Heritage Softail I purchased new in 97. She will turn 30 next year and the memories with her is whats the best part. Its a time machine as I can ride and I'm transported back to some fun CRAZY times...

I have newer bikes now that get the miles as this girl is low and takes a pot hole like a pot hole but I love the sound and feel of a cammed EVO. IF I sold all my bikes tomorrow, this bike is the one I will not part with but the one I ride the least.

Over the years ( most years she didn't sit ) she got 2x a year fluid changes a 1x or 2x a year a full 3 step polish / wax / detail as I try hard to keep her looking new and detailing motorcycles ( and riding ) is somehow "Therapy" or simply something I enjoy, If I can't sleep at 3 am I'll go to the garage and polish something...

This last oil change I noticed how clean the oil filter housing was so IMO changing mineral based oil VERY often does keep things clean. ( see pic ) She is a low mile bike with under 30K.

Tires are perhaps 4 years old now with little miles. Belt has never been changed.

I try to ride a motorcycle every day its not raining so now that she is back on the road and the carb is not acting up she will see some miles around town, My newer Street Glide gets the trips...
Some pics..

 

[SOUNDMAN5000]

UPDATE: After treating as per the Mechanic In a Bottle instructions, mixing 2 OZ per gallon of gas with good results I had the thought as long as I'm testing this stuff wonder what 100% straight Mechanic In a Bottle will do NOT mixed with gas so I thought I'll allow 100% straight MIAB to sit in the carb overnight and see what happens...


So, I turn the Petcock off, unhooked the gas at the Petcock feeding a inline filter I added years ago then to my S&S Super E carb... I found a tiny funnel to go in the end of the gas line and I add some straight Mechanic in a bottle, a few ounces the I started the engine as I kept pouring a small amount of product into the gas line I let it run till it stopped on its on, turned it over twice and let it sit now with full strength MIAB in the carb / bowl overnight, a good 12 hours.

I reconnected the fuel tank line, removed the drain plug on the bottom of the S&S carb bowl ( can you believe I have never once drained this carb after I installed and jetted it 25+ years ago ) but I then turn the gas petcock on and flush I guess a quart of gas to clean any MIAB out of the carb and then took it for a ride...

As I first start it and pull away from the house my first thought its more responsive but as I continue to ride I think its placebo...

As I type this my thought is It may be a tad better may be the same as cleaning as per directions a few days back did the trick mixing 2 oz per gallon of gas and soaking over night...

Well I can say this, me using the Mechanic In a Box 100% straight in the carb sure didn't hurt anything however IF you choose to use this product outside of the directions do so at your own risk, I can say I see no real benefit using it straight.

All and all I have ran I guess a 1/2 tank of gas after cleaning the carb with MIAB, I can say it works and works well in my specific situation . My old Snapper gets this next and the old Honda push mower does too!

Do I think the caeb is doing the job it did 27+ years ago when new... Perhaps not but its very close to new and thats impressive! My bike is starting, idle is perfect pulls hard does not even hint it will stop running... Im very happy and will always moving forward have a spot on the shelf especially Spring time when mowers can be funny.

I will add that I do think me ALWAYS using ethanol free gas, ALWAYS mixed with Sta-bil AND Marvel Mystery Oil is perhaps THE reason my S&S Super has been able to go almost three decades without a re-build and my 21+ year old lawn mowers that get little more love than a oil change and spark plug cleaning every year or so continue to run so well...

 

[JavierH19]

I think you would have been but off using Berryman's B12 which is five bucks or less for a can and it's readily available. I did the same thing to old OPE with it and it would clean it up fast and get it running good.

 

[Pete in PA]

Here's my 2 cents. Homelite string trimmer, 30 years old, had since new.
This is the year it won't start.
E0 gas, Stabil Marine, and 2 stroke oil.
Figured that's it, the diaphragms are finally done, got stiff, time for a carb rebuild.

Then I remembered I had Mechanic in a bottle.
Dumped the old gas, primed the old gas out, put the bottle in, primed it through, pulled a few times and let it sit 4 hours.

Emptied it out, put in 2 stroke gas from last years mix, and it started right up, runs perfect!
Cleaned the carb, rejuvenated the diaphragms, runs great!

I'd definitely try this stuff first, right before a carb rebuild!

 

[D1dad]

My dad passed away 5 yrs ago and his Jonsered saw has sat in my shed through every season since then. I got it out, dumped the fuel and put in my husqvarna low smoke ethanol free mix fully expecting a rebuild and fuel lines. It took awhile to clean itself up and come to full throttle. But, I ended up cutting 4 hickory trees for a July 4 cookout we have coming up. Started and ran fine ever since. Knowing my dad, who was the tightwad of all tightwads, there’s no way he used ethanol free fuel. Sometimes you get lucky I guess.

 

[zrxkawboy]

I find it interesting that the bottle gives instructions for diesel engines, but 1.5 in the SDS says "RESTRICTIONS ON USE: THIS STABILIZER IS FOR GASOLINE ENGINES ONLY".

 

[Pete in PA]

Today was my 30 some years old Homelite chainsaws turn. Ran last year, weak, didn't rev well, didn't like being angled for tree dropping.
Wouldn't start today.

Added the recommended amount Of MIB, primed it through, pulled rope a few times and let it sit for 4 hours.

Tried starting it, took several pulls, then it started. Had to play the choke back and forth a bit, then it ran. Got to running stronger than it has in years.

Cut up a small dead tree, and cut down another leaning small tree. Works great!

I'm sold! Stuff really works!

 

[4wd]

That Chic mechanic likes it - I have used it in the LT42 as PM